Rapid test method for insulation resistance of energy storage device

Abstract

A rapid test method for an insulation resistance of an energy storage device. The method comprises: obtaining a plurality of first test voltages and a plurality of second test voltages for the energy storage device (S101); on the basis of the first test voltages at a plurality of sampling moments, determining a first steady-state voltage of a first sampling resistor, and on the basis of the second test voltages at the plurality of sampling moments, determining a second steady-state voltage of a second sampling resistor (S102); on the basis of the first steady-state voltage and the second steady-state voltage, determining a positive ground steady-state voltage and a negative ground steady-state voltage of the energy storage device (S103); and on the basis of the positive ground steady-state voltage and the negative ground steady-state voltage, estimating an insulation resistance of the energy storage device (S104). The problem in the prior art that the time for determining a fault is long due to the fact that it is necessary to wait for the sampling voltage to be stable before the insulation resistance can be calculated, and the problem in the prior art that the impact of a Y capacitor of the energy storage device on the insulation resistance test is not considered are solved, so that the effects of reducing the test time and improving the test accuracy are achieved.

Description

A method for quickly detecting insulation resistance of energy storage equipment

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure claims priority to Chinese patent application number 202311213017.0, filed with the State Intellectual Property Office of China on September 20, 2023, entitled “A method for rapid detection of insulation resistance of energy storage equipment,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to the technical field of energy storage devices, and in particular to a method for quickly detecting the insulation resistance of an energy storage device. Background Art

[0004] Energy storage devices require insulation testing before being connected to a high-voltage power supply. Existing insulation testing methods require sampling the insulation steady-state voltage to accurately calculate the insulation resistance value. However, the parasitic Y capacitance of energy storage devices is large. If multiple energy storage devices are connected in parallel, the parasitic Y capacitance increases, causing the time for the insulation sampling voltage to reach a steady state to increase exponentially, thereby increasing the detection time, affecting the high voltage on the energy storage device, and may also result in insulation faults in the energy storage device being unable to be diagnosed and reported in a timely manner, affecting safety.

[0005] Summary of the Invention

[0006] In view of this, the present disclosure aims to provide at least one method for rapidly detecting the insulation resistance of an energy storage device. The method periodically obtains the voltage across a sampling resistor in two different circuit structures of an insulation resistance detection circuit, calculates the steady-state voltage across the sampling resistor based on each sampling moment and the voltage value corresponding to that sampling moment, and further calculates the positive steady-state voltage and negative steady-state voltage of the energy storage device. Furthermore, based on the positive steady-state voltage and negative steady-state voltage under the two circuit structures, the positive insulation resistance and negative insulation resistance of the energy storage device are calculated, thereby determining the insulation resistance of the energy storage device. This method facilitates determining whether an insulation fault exists in the energy storage device, and solves the technical problems in the prior art of requiring a long fault determination time due to waiting for the sampling voltage to stabilize before calculating the insulation resistance, as well as the technical problem in the prior art of not considering the effect of the Y capacitor of the energy storage device on insulation resistance detection. The method achieves the technical advantages of reducing detection time, shortening fault reporting time, improving safety, and considering the Y capacitor of the energy storage device to improve detection accuracy.

[0007] This disclosure mainly includes the following aspects:

[0008] In a first aspect, an embodiment of the present disclosure provides a method for quickly detecting the insulation resistance of an energy storage device, the method comprising: obtaining multiple first detection voltages and multiple second detection voltages for the energy storage device; determining a first steady-state voltage of a first sampling resistor based on the first detection voltages at multiple sampling moments, and determining a second steady-state voltage of a second sampling resistor based on the second detection voltages at multiple sampling moments; determining a positive steady-state voltage to ground and a negative steady-state voltage to ground of the energy storage device based on the first steady-state voltage and the second steady-state voltage; and estimating the insulation resistance of the energy storage device based on the positive steady-state voltage to ground and the negative steady-state voltage to ground.

[0009] Optionally, each first detection voltage refers to the voltage of a first sampling resistor on a first sampling circuit located between the positive electrode of the energy storage device and a preset ground terminal at each sampling moment, and each second detection voltage refers to the voltage of a second sampling resistor on a second sampling circuit located between the negative electrode of the energy storage device and the preset ground terminal at each sampling moment.

[0010] Optionally, the first sampling circuit is a positive half-bridge sampling circuit, and the second sampling circuit is a negative half-bridge sampling circuit.

[0011] Optionally, the positive steady-state voltage to ground refers to the voltage of the positive pole of the energy storage device relative to the preset ground terminal when the energy storage device is in an insulating steady-state state, and the negative steady-state voltage to ground refers to the voltage of the negative pole of the energy storage device relative to the preset ground terminal when the energy storage device is in an insulating steady-state state.

[0012] Optionally, the steady-state voltage is determined based on a resistor-capacitor charge-discharge time formula, which is used to characterize the relationship between the detection voltage and the steady-state voltage, wherein the detection voltage is equal to the sum of the steady-state voltage and an exponential term, and the exponential term includes the product of a coefficient and a natural exponential term with respect to time.

[0013] Optionally, the steady-state voltage is determined in the following manner: based on the resistor-capacitor charge-discharge time formula, a plurality of sampling moments and their corresponding detection voltages are used to obtain the steady-state voltage.

[0014] Optionally, the steady-state voltage is determined in the following manner: based on a linear formula, multiple sampling moments and their corresponding detection voltages are used to obtain the constant term and slope of the linear formula, where the independent variable of the linear formula is the sampling moment and the dependent variable is the detection voltage; based on the constant term and slope of the linear formula, the exponential term in the resistor and capacitor charge and discharge time formula is determined, where the resistor and capacitor charge and discharge time formula is used to characterize the relationship between the detection voltage and the steady-state voltage, where the detection voltage is equal to the sum of the steady-state voltage and the exponential term; based on the resistor and capacitor charge and discharge time formula, the steady-state voltage is obtained using any sampling moment and its corresponding detection voltage.

[0015] Optionally, the first sampling circuit includes a first resistor, a second resistor, and a third resistor, wherein the first resistor is arranged between the positive electrode of the energy storage device and the preset ground terminal, the second resistor and the third resistor are connected in series and connected in parallel with the first resistor, and the first sampling resistor is one of the second resistor and the third resistor; and / or, the second sampling circuit includes a fourth resistor, a fifth resistor, and a sixth resistor, wherein the fourth resistor is arranged between the negative electrode of the energy storage device and the preset ground terminal, the fifth resistor and the sixth resistor are connected in series and connected in parallel with the fourth resistor, and the second sampling resistor is one of the fifth resistor and the sixth resistor.

[0016] Optionally, the first sampling circuit further includes a first detection switch disposed on a branch where the second resistor and the third resistor are connected in series, and the second sampling circuit further includes a second detection switch disposed on a branch where the fifth resistor and the sixth resistor are connected in series.

[0017] Optionally, the multiple first detection voltages include a voltage of the first sampling resistor collected when only the first detection switch is closed, and / or a voltage of the first sampling resistor collected when the first detection switch and the second detection switch are simultaneously closed; the multiple second detection voltages include a voltage of the second sampling resistor collected when only the second detection switch is closed, and / or a voltage of the second sampling resistor collected when the first detection switch and the second detection switch are simultaneously closed.

[0018] Optionally, obtaining the plurality of first detection voltages and the plurality of second detection voltages for the energy storage device includes: determining a positive ground-referenced steady-state voltage and a negative ground-referenced steady-state voltage of the energy storage device when the first detection switch and the second detection switch are simultaneously closed; determining a target detection switch based on a comparison result between the positive ground-referenced steady-state voltage and the negative ground-referenced steady-state voltage, where the target detection switch is one of the first detection switch and the second detection switch; and determining a voltage of a sampling resistor corresponding to when only the target detection switch is closed, and a voltage of the first sampling resistor and a voltage corresponding to the second sampling resistor corresponding to when the first detection switch and the second detection switch are simultaneously closed, as the plurality of first detection voltages and the plurality of second detection voltages for the energy storage device.

[0019] Optionally, the positive steady-state voltage to ground of the energy storage device includes a first positive steady-state voltage to ground and a second positive steady-state voltage to ground, and the negative steady-state voltage to ground includes a first negative steady-state voltage to ground and a second negative steady-state voltage to ground. The first positive steady-state voltage to ground is determined based on a voltage corresponding to a first sampling resistor when the first detection switch and the second detection switch are simultaneously closed. The first negative steady-state voltage to ground is determined based on a voltage corresponding to a second sampling resistor when the first detection switch and the second detection switch are simultaneously closed. The first target steady-state voltage is determined based on a voltage corresponding to the sampling resistor when only the target detection switch is closed. The second target steady-state voltage is determined based on a voltage between the positive and negative electrodes of the energy storage device and the first target steady-state voltage. The first target steady-state voltage is one of the second positive steady-state voltage to ground and the second negative steady-state voltage to ground, and the second target steady-state voltage is the other of the second positive steady-state voltage to ground and the second negative steady-state voltage to ground.

[0020] Optionally, the insulation resistance of the energy storage device is estimated by: determining a first positive equivalent resistance to ground and a first negative equivalent resistance to ground when the first detection switch and the second detection switch are simultaneously closed, and determining a second positive equivalent resistance to ground and a second negative equivalent resistance to ground when only the target detection switch is closed;

[0021] A first equation is constructed based on the first positive steady-state voltage to ground, the first negative steady-state voltage to ground, the first positive equivalent resistance to ground, and the first negative equivalent resistance to ground, where one side of the first equation is the ratio of the first positive steady-state voltage to ground to the first negative steady-state voltage to ground, and the other side of the first equation is the ratio of the first positive equivalent resistance to ground to the first negative equivalent resistance to ground; a second equation is constructed based on the second positive steady-state voltage to ground, the second negative steady-state voltage to ground, the second positive equivalent resistance to ground, and the second negative equivalent resistance to ground, where one side of the second equation is the ratio of the second positive steady-state voltage to ground to the second negative steady-state voltage to ground, and the other side of the second equation is the ratio of the second positive equivalent resistance to ground to the second negative equivalent resistance to ground; the first equation and the second equation are combined to calculate the positive insulation resistance and the negative insulation resistance of the energy storage device; and the insulation resistance of the energy storage device is estimated based on the comparison result of the positive insulation resistance and the negative insulation resistance.

[0022] In a second aspect, an embodiment of the present disclosure further provides an insulation resistance detection circuit, comprising: a ground switch disposed between a preset ground terminal of the insulation resistance detection circuit and a local ground terminal of an energy storage device; a first sampling circuit disposed between a positive electrode of the energy storage device and the preset ground terminal, the first sampling circuit comprising multiple resistors, and collecting a first detection voltage of the first sampling resistor at each sampling moment, the first sampling resistor being one of the multiple resistors included in the first sampling circuit; a second sampling circuit disposed between a negative electrode of the energy storage device and the preset ground terminal, the second sampling circuit comprising multiple resistors, and collecting a second detection voltage of the second sampling resistor at each sampling moment, the second sampling resistor being one of the multiple resistors included in the second sampling circuit; and a processor, configured to execute the method for rapid insulation resistance detection as described in the first aspect or any possible implementation manner of the first aspect.

[0023] Optionally, the first sampling circuit includes: a first detection switch, a first resistor, a second resistor, a third resistor, and a first voltmeter, wherein the first sampling resistor is one of the second resistor and the third resistor, wherein the first resistor is arranged between the positive electrode of the energy storage device and the preset ground terminal, the second resistor, the third resistor, and the first detection switch are connected in series and then connected in parallel with the first resistor, the first voltmeter is connected in parallel across the first sampling resistor, and the first voltmeter is connected to the processor to send the first detection voltage collected at each sampling moment to the processor.

[0024] Optionally, the second sampling circuit includes: a second detection switch, a fourth resistor, a fifth resistor, a sixth resistor, and a second voltmeter, the second sampling resistor is one of the fifth resistor and the sixth resistor, wherein the fourth resistor is arranged between the negative electrode of the energy storage device and the preset ground terminal, the fifth resistor, the sixth resistor, and the second detection switch are connected in series and then connected in parallel with the fourth resistor, the second voltmeter is connected in parallel across the second sampling resistor, and the second voltmeter is connected to the processor to send the second detection voltage collected at each sampling moment to the processor.

[0025] Optionally, the resistance of the first sampling resistor is smaller than the resistance of the first preset resistor, the resistance of the first sampling resistor is smaller than the resistance of the first resistor, and the first preset resistor is the other of the second resistor and the third resistor.

[0026] Optionally, the resistance of the second sampling resistor is smaller than the resistance of the second preset resistor, the resistance of the second sampling resistor is smaller than the resistance of the fourth resistor, and the second preset resistor is the other of the fifth resistor and the sixth resistor.

[0027] An embodiment of the present disclosure provides a rapid method for detecting the insulation resistance of an energy storage device. The method includes: obtaining multiple first detection voltages and multiple second detection voltages for the energy storage device; determining a first steady-state voltage of a first sampling resistor based on the first detection voltages at multiple sampling moments, and determining a second steady-state voltage of a second sampling resistor based on the second detection voltages at multiple sampling moments; determining a positive steady-state voltage to ground and a negative steady-state voltage to ground of the energy storage device based on the first steady-state voltage and the second steady-state voltage; and estimating the insulation resistance of the energy storage device based on the positive steady-state voltage to ground and the negative steady-state voltage to ground. By periodically acquiring the voltage values ​​across the sampling resistor of the insulation resistance detection circuit under two different circuit structures, the steady-state voltage value across the sampling resistor is calculated based on each sampling moment and the voltage value corresponding to that sampling moment, thereby calculating the positive steady-state voltage and negative steady-state voltage to ground of the energy storage device. Furthermore, based on the positive steady-state voltage and negative steady-state voltage to ground under the two circuit structures, the positive insulation resistance and negative insulation resistance of the energy storage device are calculated, thereby determining the insulation resistance of the energy storage device. This facilitates determining whether the energy storage device has an insulation fault, solving the technical problems in the prior art of requiring a long fault determination time due to waiting for the sampling voltage to stabilize before calculating the insulation resistance, and the technical problem in the prior art of not considering the effect of the Y capacitor of the energy storage device on insulation resistance detection. This achieves the technical effects of reducing detection time, shortening fault reporting time, improving safety, and considering the Y capacitor of the energy storage device to improve detection accuracy.

[0028] In order to make the above-mentioned objectives, features and advantages of the present disclosure more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present disclosure and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0030] FIG1 shows a flow chart of a method for quickly detecting insulation resistance of an energy storage device provided by an embodiment of the present disclosure.

[0031] FIG2 shows a schematic diagram of a first sampling circuit and a second sampling circuit provided by an embodiment of the present disclosure.

[0032] FIG3 shows a flowchart of steps for obtaining a plurality of first detection voltages and a plurality of second detection voltages for the energy storage device provided by an embodiment of the present disclosure.

[0033] FIG4 shows a circuit diagram of an insulation resistance detection circuit provided by an embodiment of the present disclosure. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the embodiments of the present disclosure clearer, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. It should be understood that the drawings in the present disclosure are only for the purpose of illustration and description and are not used to limit the scope of protection of the present disclosure. In addition, it should be understood that the schematic drawings are not drawn to scale. The flowcharts used in the present disclosure illustrate operations implemented according to some embodiments of the present disclosure. It should be understood that the operations of the flowchart can be implemented out of sequence, and steps that have no logical contextual relationship can be reversed or implemented simultaneously. In addition, those skilled in the art, guided by the contents of the present disclosure, can add one or more other operations to the flowchart, or remove one or more operations from the flowchart.

[0035] In addition, the described embodiments are only a part of the embodiments of the present disclosure, rather than all of the embodiments. The components of the embodiments of the present disclosure generally described and shown in the drawings herein can be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of the present disclosure provided in the drawings is not intended to limit the scope of the disclosure claimed for protection, but merely represents selected embodiments of the present disclosure. Based on the embodiments of the present disclosure, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present disclosure.

[0036] In the prior art, since the energy storage device includes a capacitor, the capacitor needs to be charged before the insulation resistance test of the energy storage device is performed. As a result, the voltage across the insulation resistance of the energy storage device takes some time to stabilize, resulting in a long time to determine the specific resistance value of the insulation resistance, and thus a long detection time before the energy storage device is applied with high voltage.

[0037] Based on this, the embodiment of the present disclosure provides a method for quickly detecting the insulation resistance of an energy storage device. By periodically obtaining the voltage value across the sampling resistor of the insulation resistance detection circuit under two different circuit structures, the steady-state voltage value across the sampling resistor is calculated based on each sampling moment and the voltage value corresponding to the sampling moment, and then the positive steady-state voltage to ground and the negative steady-state voltage to ground of the energy storage device are calculated. Then, based on the positive steady-state voltage to ground and the negative steady-state voltage to ground under the two circuit structures, the positive insulation resistance to ground and the negative insulation resistance to ground of the energy storage device are calculated, thereby determining the insulation resistance of the energy storage device. This facilitates determining whether the energy storage device has an insulation fault, solving the technical problem in the prior art that the insulation resistance needs to be calculated only after the sampling voltage stabilizes, resulting in a long fault judgment time, and the technical problem in the prior art that the influence of the Y capacitor of the energy storage device on the insulation resistance detection is not considered, achieving the technical effect of reducing detection time, shortening fault reporting time, improving safety, and considering the Y capacitor of the energy storage device to improve detection accuracy. The details are as follows:

[0038] Please refer to Figure 1, which is a flow chart of a method for quickly detecting the insulation resistance of an energy storage device provided by an embodiment of the present disclosure. As shown in Figure 1, the method for quickly detecting the insulation resistance of an energy storage device includes:

[0039] S101: Acquire a plurality of first detection voltages and a plurality of second detection voltages for the energy storage device.

[0040] Each first detection voltage refers to the voltage of a first sampling resistor on a first sampling circuit between the positive electrode of the energy storage device and the preset ground terminal at each sampling moment, and each second detection voltage refers to the voltage of a second sampling resistor on a second sampling circuit between the negative electrode of the energy storage device and the preset ground terminal at each sampling moment.

[0041] The interval between adjacent sampling moments is a fixed value, that is, the voltage across the first sampling resistor is sampled at intervals of a preset period, and the voltage across the second sampling resistor is sampled at intervals of a preset period.

[0042] Please refer to FIG. 2 , which is a schematic diagram of a first sampling circuit and a second sampling circuit provided by an embodiment of the present disclosure.

[0043] As shown in FIG2 , the first sampling circuit 10 includes a first resistor R1, a second resistor R2, and a third resistor R3, wherein the first resistor R1 is arranged between the positive electrode Bat+ of the energy storage device and the preset ground terminal PE, the second resistor and the third resistor are connected in series and connected in parallel with the first resistor, and the first sampling resistor is one of the second resistor and the third resistor, and / or the second sampling circuit 20 includes a fourth resistor R4, a fifth resistor R5, and a sixth resistor R6, wherein the fourth resistor is arranged between the negative electrode Bat- of the energy storage device and the preset ground terminal PE, the fifth resistor and the sixth resistor are connected in series and connected in parallel with the fourth resistor, and the second sampling resistor is one of the fifth resistor and the sixth resistor.

[0044] The first sampling circuit is one of a positive half-bridge sampling circuit and a negative half-bridge sampling circuit, and the second sampling circuit is the other of the positive half-bridge sampling circuit and the negative half-bridge sampling circuit. Since the first sampling circuit is arranged between the positive electrode of the energy storage device and the preset ground terminal, the first sampling circuit is a positive half-bridge sampling circuit, and the second sampling circuit is arranged between the negative electrode of the energy storage device and the preset ground terminal, the second sampling circuit is a negative half-bridge sampling circuit.

[0045] That is, because the second and third resistors are connected in series, in parallel with the positive electrode of the energy storage device and the preset ground terminal, the voltage across each first sampling resistor is a portion of the voltage between the positive electrode of the energy storage device and the preset ground terminal at each sampling moment. Consequently, each first detection voltage is a portion of the voltage between the positive electrode of the energy storage device and the preset ground terminal at each sampling moment. Similarly, each second detection voltage is a portion of the voltage between the negative electrode of the energy storage device and the preset ground terminal at each sampling moment.

[0046] The first sampling circuit further includes a first detection switch K1 disposed on a branch where a second resistor and a third resistor are connected in series. The second sampling circuit further includes a second detection switch K2 disposed on a branch where a fifth resistor and a sixth resistor are connected in series. The multiple first detection voltages include a voltage of the first sampling resistor collected when only the first detection switch is closed, and / or a voltage of the first sampling resistor collected when the first detection switch and the second detection switch are simultaneously closed. The multiple second detection voltages include a voltage of the second sampling resistor collected when only the second detection switch is closed, and / or a voltage of the second sampling resistor collected when the first detection switch and the second detection switch are simultaneously closed.

[0047] When the first detection switch and the second detection switch are closed at the same time, the first detection voltage and the second detection voltage collected at each sampling moment are acquired. That is, when the first detection switch and the second detection switch are closed at the same time, the first detection voltage and the second detection voltage are collected at the same time.

[0048] The multiple first detection voltages and the multiple second detection voltages include the following two cases: in case 1, the multiple first detection voltages include the voltage of the first sampling resistor corresponding to each sampling moment when only the first detection switch is closed, and the voltage of the first sampling resistor corresponding to each sampling moment when the first detection switch and the second detection switch are simultaneously closed; the multiple second detection voltages include the voltage of the second sampling resistor corresponding to each sampling moment when the first detection switch and the second detection switch are simultaneously closed; in case 2, the multiple first detection voltages include the voltage of the first sampling resistor corresponding to each sampling moment when the first detection switch and the second detection switch are simultaneously closed; the multiple second detection voltages include the voltage of the second sampling resistor corresponding to each sampling moment when only the second detection switch is closed, and the voltage of the second sampling resistor corresponding to each sampling moment when the first detection switch and the second detection switch are simultaneously closed.

[0049] Please refer to Figure 3, which is a flow chart of the steps of obtaining multiple first detection voltages and multiple second detection voltages for the energy storage device according to an embodiment of the present disclosure. As shown in Figure 3, obtaining multiple first detection voltages and multiple second detection voltages for the energy storage device includes:

[0050] S1011: Determine a positive ground-referenced steady-state voltage and a negative ground-referenced steady-state voltage of the energy storage device when the first detection switch and the second detection switch are closed simultaneously.

[0051] Specifically, when the first detection switch and the second detection switch are closed simultaneously, the steady-state voltage across the first sampling resistor and the steady-state voltage across the second sampling resistor are determined based on the voltage across the first sampling resistor and the voltage across the second sampling resistor at each sampling moment. Furthermore, the positive ground reference steady-state voltage and the negative ground reference steady-state voltage of the energy storage device are determined based on the steady-state voltage across the first sampling resistor and the steady-state voltage across the second sampling resistor.

[0052] That is to say, the positive reference steady-state voltage to ground refers to the voltage of the positive electrode of the energy storage device relative to the preset ground terminal when the first detection switch and the second detection switch are closed at the same time, and the negative reference steady-state voltage to ground refers to the voltage of the negative electrode of the energy storage device relative to the preset ground terminal when the first detection switch and the second detection switch are closed at the same time.

[0053] S1012: Determine a target detection switch according to a comparison result between the positive ground reference steady-state voltage and the negative ground reference steady-state voltage.

[0054] The target detection switch is one of the first detection switch and the second detection switch.

[0055] Specifically, when the positive reference steady-state voltage to ground is greater than or equal to the negative reference steady-state voltage to ground, the target detection switch is determined to be the first detection switch; when the positive reference steady-state voltage to ground is less than the negative reference steady-state voltage to ground, the target detection switch is determined to be the second detection switch.

[0056] When the voltage is higher, the sampling process is less affected by external factors, and thus the sampling error is smaller, and the predicted values ​​of the positive half-bridge steady-state voltage and the negative half-bridge steady-state voltage are more accurate.

[0057] S1013: Determine a voltage of the sampling resistor corresponding to when only the target detection switch is closed, and a voltage of the first sampling resistor and a voltage corresponding to the second sampling resistor corresponding to when the first detection switch and the second detection switch are simultaneously closed as a plurality of first detection voltages and a plurality of second detection voltages for the energy storage device.

[0058] That is, when the first detection switch and the second detection switch are closed at the same time, the voltage of the first sampling resistor corresponding to each sampling moment and the voltage of the second sampling resistor corresponding to each sampling moment are determined; the positive reference steady-state voltage to the ground and the negative reference steady-state voltage to the ground of the energy storage device are determined based on the collected voltages; when the positive reference steady-state voltage to the ground is greater than or equal to the negative reference steady-state voltage to the ground, the voltage of the first sampling resistor corresponding to each sampling moment when only the first detection switch is closed is determined; the voltage of the first sampling resistor corresponding to each sampling moment when the first detection switch and the second detection switch are closed at the same time, and the voltage of the first sampling resistor corresponding to each sampling moment when only the first detection switch is closed are used as a plurality of first detection voltages. voltage, using the voltage of the second sampling resistor corresponding to each sampling moment when the first detection switch and the second detection switch are simultaneously closed as a plurality of second detection voltages; when the positive reference steady-state voltage to the ground is less than the negative reference steady-state voltage to the ground, determining the voltage of the second sampling resistor corresponding to each sampling moment when only the second detection switch is closed; using the voltage of the first sampling resistor corresponding to each sampling moment when the first detection switch and the second detection switch are simultaneously closed as a plurality of first detection voltages, using the voltage of the second sampling resistor corresponding to each sampling moment when the first detection switch and the second detection switch are simultaneously closed, and using the voltage of the second sampling resistor corresponding to each sampling moment when only the second detection switch is closed as a plurality of second detection voltages.

[0059] S102: determining a first steady-state voltage of a first sampling resistor according to a first detection voltage at a plurality of sampling moments, and determining a second steady-state voltage of a second sampling resistor according to a second detection voltage at a plurality of sampling moments.

[0060] The first steady-state voltage and the second steady-state voltage are determined in the same manner. Therefore, the first steady-state voltage and the second steady-state voltage are referred to as steady-state voltages, and the first detection voltage and the second detection voltage are referred to as detection voltages.

[0061] The steady-state voltage is determined based on a resistor-capacitor charge-discharge time formula, where the resistor-capacitor charge-discharge time formula is used to characterize the relationship between the detection voltage and the steady-state voltage, wherein the detection voltage is equal to the sum of the steady-state voltage and an exponential term, where the exponential term includes the product of a coefficient and a natural exponential term with respect to time; wherein the steady-state voltage is determined in the following manner: based on the resistor-capacitor charge-discharge time formula, a plurality of sampling moments and their corresponding detection voltages are used to obtain the steady-state voltage.

[0062] The formula for the charge and discharge time of resistors and capacitors is:

[0063] In formula (1), t i Refers to the i-th sampling moment; is the detection voltage at the i-th sampling moment; V f for The steady-state value of , that is, the steady-state voltage; is the exponential term, (V0-V f ) is the coefficient of the exponential term, is the natural exponential term about time; V0 is R refers to the equivalent resistance in the equivalent circuit across the sampling resistor corresponding to the detection voltage; C can be understood as the equivalent capacitance in the equivalent circuit across the sampling resistor corresponding to the detection voltage. This equivalent capacitance is not the equivalent capacitance in the equivalent circuit across the sampling resistor corresponding to the detection voltage in a purely physical sense. Since the specific values ​​of R and C in the present disclosure do not affect the calculation of the present disclosure, for ease of understanding, C can be considered as the equivalent capacitance in the equivalent circuit across the sampling resistor corresponding to the detection voltage.

[0064] The first steady-state voltage is determined by the following resistor-capacitor charge-discharge time formula:

[0065] In formula (2), t i Refers to the i-th sampling moment of collecting the first detection voltage; is the first detection voltage collected at the i-th sampling moment; V f，1 for Steady-state value; V 0,1 for The initial value of R1 refers to the equivalent resistance in the equivalent circuit across the first sampling resistor after the first sampling circuit is connected to the positive electrode of the energy storage device and the preset ground terminal; C1 can be understood as the equivalent capacitance in the equivalent circuit across the first sampling resistor after the first sampling circuit is connected to the positive electrode of the energy storage device and the preset ground terminal. Since the equivalent capacitance is also affected by the equivalent capacitance in the equivalent circuit after the second sampling circuit is connected to the negative electrode of the energy storage device and the preset ground terminal, C1 is not the equivalent capacitance in the equivalent circuit across the first sampling resistor after the first sampling circuit is connected to the positive electrode of the energy storage device and the preset ground terminal in a purely physical sense. Since the specific values ​​of R1 and C1 in the present disclosure do not affect the calculation of the present disclosure, for the sake of ease of understanding, C1 can be considered as the equivalent capacitance in the equivalent circuit across the first sampling resistor after the first sampling circuit is connected to the positive electrode of the energy storage device and the preset ground terminal; A is V f，1 The simplified symbol of B is (V 0，1 -V f，1 ), D is Simplified symbol of .

[0066] The second steady-state voltage is determined by the following resistor-capacitor charge-discharge time formula:

[0067] In formula (3), t i Refers to the i-th sampling moment of collecting the second detection voltage; is the second detection voltage collected at the i-th sampling moment; V f，2 for Steady-state value; V 0,2 for The initial value of R2 refers to the equivalent resistance in the equivalent circuit across the second sampling resistor after the second sampling circuit is connected to the negative electrode of the energy storage device and the preset ground terminal; C2 can be understood as the equivalent capacitance in the equivalent circuit across the second sampling resistor after the second sampling circuit is connected to the negative electrode of the energy storage device and the preset ground terminal. Since the equivalent capacitance is also affected by the equivalent capacitance in the equivalent circuit after the first sampling circuit is connected to the positive electrode of the energy storage device and the preset ground terminal, C2 is not the equivalent capacitance in the equivalent circuit across the second sampling resistor after the second sampling circuit is connected to the negative electrode of the energy storage device and the preset ground terminal in a purely physical sense. Since the specific values ​​of R2 and C2 in the present disclosure do not affect the calculation of the present disclosure, for ease of understanding, C2 can be considered as the equivalent capacitance in the equivalent circuit across the second sampling resistor after the second sampling circuit is connected to the negative electrode of the energy storage device and the preset ground terminal; A′ is V f，2 The simplified symbol of B′ is (V 0，2 -V f，2 ), D′ is Simplified symbol of .

[0068] Furthermore, when the first detection switch and the second detection switch are closed at the same time, the voltage of each sampling moment and the corresponding first sampling resistor are substituted into formula (2) to solve V in formula (2). f，1 , that is, the steady-state voltage of the first sampling resistor when the first detection switch and the second detection switch are closed at the same time is obtained. Substitute the voltage of the second sampling resistor at each sampling moment and its corresponding voltage into formula (3) to solve V in formula (3) f，2 , that is, the steady-state voltage of the second sampling resistor when the first detection switch and the second detection switch are closed at the same time is obtained; if only the first detection switch is closed, the voltage of the first sampling resistor at each sampling moment and its corresponding voltage are substituted into formula (2) to solve V in formula (2) f，1 , that is, the steady-state voltage of the first sampling resistor when only the first detection switch is closed is obtained; if only the second detection switch is closed, the voltage of the second sampling resistor at each sampling moment and its corresponding voltage are substituted into formula (3) to solve V in formula (3) f，2 , that is, the steady-state voltage of the second sampling resistor when only the second detection switch is closed is obtained.

[0069] Use the least squares method with forgetting factor and Kalman filter and other nonlinear equation calculation methods to solve V f，1 、V f，2 The specific calculation method is an existing technology and will not be described in detail here.

[0070] The steady-state voltage is determined in the following manner: based on a linear formula, multiple sampling moments and their corresponding detection voltages are used to obtain the constant term and slope of the linear formula, where the independent variable of the linear formula is the sampling moment and the dependent variable is the detection voltage; based on the constant term and slope of the linear formula, the exponential term in the resistor and capacitor charge and discharge time formula is determined, where the resistor and capacitor charge and discharge time formula is used to characterize the relationship between the detection voltage and the steady-state voltage, where the detection voltage is equal to the sum of the steady-state voltage and the exponential term; based on the resistor and capacitor charge and discharge time formula, the steady-state voltage is obtained using any sampling moment and its corresponding detection voltage.

[0071] Specifically, by taking the derivative of both sides of formula (1), we can get Then take the logarithm of both sides of the derivative equation and get Then convert the logarithmic equation into a linear form and get Similarly, we can get the linear equation u(t i )1=ln(B×D)+D×t i , the linear equation u(t i)2=ln(B′×D′)+D′×t i .

[0072] That is, the linear equation is:

[0073] In formula (4), u(t i ) is the detection voltage and is the dependent variable; is a constant term; is the slope; t i is the sampling time, and is the independent variable.

[0074] Then, each sampling moment is brought into u(t i )1=ln(B×D)+D×t i t in i , the first detection voltage corresponding to the sampling moment is brought into u(t i )1=ln(B×D)+D×t i u(t i )1, solve B and D by linear least squares method; then, substitute the solved B and D into formula (2), and substitute t in formula (2) at each sampling time. i , substitute the first detection voltage corresponding to the sampling moment into the formula (2) Obtain A corresponding to each sampling moment in formula (2), and take the average value of A corresponding to each sampling time as the first steady-state voltage, or take A corresponding to any sampling moment as the first steady-state voltage. Similarly, the second steady-state voltage can be calculated.

[0075] S103: Determine a positive steady-state voltage relative to ground and a negative steady-state voltage relative to ground of the energy storage device according to the first steady-state voltage and the second steady-state voltage.

[0076] The positive steady-state voltage to ground refers to the voltage of the positive electrode of the energy storage device relative to the preset ground terminal when the energy storage device is in an insulating steady-state state, and the negative steady-state voltage to ground refers to the voltage of the negative electrode of the energy storage device relative to the preset ground terminal when the energy storage device is in an insulating steady-state state.

[0077] The positive steady-state voltage to ground of the energy storage device includes a first positive steady-state voltage to ground and a second positive steady-state voltage to ground, and the negative steady-state voltage to ground includes a first negative steady-state voltage to ground and a second negative steady-state voltage to ground. The first positive steady-state voltage to ground is determined based on a voltage corresponding to a first sampling resistor when the first detection switch and the second detection switch are simultaneously closed. The first negative steady-state voltage to ground is determined based on a voltage corresponding to a second sampling resistor when the first detection switch and the second detection switch are simultaneously closed. The first target steady-state voltage is determined based on a voltage corresponding to the sampling resistor when only the target detection switch is closed. The second target steady-state voltage is determined based on a voltage between the positive and negative electrodes of the energy storage device and the first target steady-state voltage. The first target steady-state voltage is one of the second positive steady-state voltage to ground and the second negative steady-state voltage to ground, and the second target steady-state voltage is the other of the second positive steady-state voltage to ground and the second negative steady-state voltage to ground.

[0078] That is, when the first detection switch and the second detection switch are simultaneously closed, the steady-state voltage of the first sampling resistor is determined based on the voltage of the first sampling resistor corresponding to each sampling moment, and the steady-state voltage of the second sampling resistor is determined based on the voltage of the second sampling resistor corresponding to each sampling moment. Furthermore, based on the circuit between the first sampling circuit and the positive electrode of the energy storage device and the preset ground terminal, a first positive steady-state voltage to ground is calculated between the positive electrode of the energy storage device and the preset ground terminal; and based on the circuit between the second sampling circuit and the negative electrode of the energy storage device and the preset ground terminal, a first negative steady-state voltage to ground is calculated between the negative electrode of the energy storage device and the preset ground terminal.

[0079] The first positive steady-state voltage to ground is calculated in the following manner: a current flowing through the first sampling resistor in an insulated steady state is determined based on the steady-state voltage of the first sampling resistor and the resistance value of the first sampling resistor; and a first positive steady-state voltage to ground is calculated between the positive electrode of the energy storage device and a preset ground terminal based on the current flowing through the first sampling resistor and the circuit structure of the first sampling circuit.

[0080] The first negative steady-state voltage to ground is calculated by: determining a current flowing through the second sampling resistor in an insulated steady-state condition based on the steady-state voltage of the second sampling resistor and the resistance value of the second sampling resistor; and calculating the first negative steady-state voltage to ground between the negative electrode of the energy storage device and a preset ground terminal based on the current flowing through the second sampling resistor and the circuit structure of the second sampling circuit.

[0081] For example, as shown in FIG2 , the third resistor is the first sampling resistor, and the sixth resistor is the second sampling resistor. If the first detection switch and the second detection switch are closed at the same time, the steady-state voltage across the first sampling resistor is V1, and the steady-state voltage across the second sampling resistor is V2. Thus, the first positive steady-state voltage to ground is V1. First negative steady-state voltage to ground

[0082] When only the target detection switch is closed, a first target steady-state voltage is determined according to the voltage of the sampling resistor corresponding to the target detection switch, and a second target steady-state voltage is determined according to the voltage between the positive and negative electrodes of the energy storage device and the first target steady-state voltage. The first target steady-state voltage is one of the second positive steady-state voltage to ground and the second negative steady-state voltage to ground, and the second target steady-state voltage is the other of the second positive steady-state voltage to ground and the second negative steady-state voltage to ground.

[0083] When the target detection switch is the first detection switch, the steady-state voltage of the first sampling resistor is determined based on the voltage of the first sampling resistor at each sampling moment; the current flowing through the first sampling resistor is determined based on the steady-state voltage of the first sampling resistor and the resistance value of the first sampling resistor; the second positive steady-state voltage to ground is determined based on the current flowing through the first sampling resistor and the circuit structure of the positive half-bridge detection circuit; and the second negative steady-state voltage to ground is obtained by adding the voltage between the positive and negative electrodes of the energy storage device to the second positive steady-state voltage to ground.

[0084] When the target detection switch is the second detection switch, the steady-state voltage of the second sampling resistor is determined based on the voltage of the second sampling resistor at each sampling moment; the current flowing through the second sampling resistor is determined based on the steady-state voltage of the second sampling resistor and the resistance value of the second sampling resistor; the second negative steady-state voltage to ground is determined based on the current flowing through the second sampling resistor and the circuit structure of the negative half-bridge detection circuit; and the second positive steady-state voltage to ground is obtained by adding the voltage between the positive and negative electrodes of the energy storage device to the second negative steady-state voltage to ground.

[0085] For example, as shown in FIG2 , when only the first detection switch is closed, the steady-state voltage across the first sampling resistor is V3, and the second steady-state voltage to ground is V3. The second negative steady-state voltage to ground is U4=U Bat -U3, where U Bat It is the voltage between the positive and negative electrodes of the energy storage device.

[0086] That is, the first positive steady-state voltage to ground is the voltage of the positive electrode relative to the preset ground terminal when the first detection switch and the second detection switch are closed at the same time and the energy storage device is in an insulated steady-state state; the first negative steady-state voltage to ground is the voltage of the negative electrode relative to the preset ground terminal when the first detection switch and the second detection switch are closed at the same time and the energy storage device is in an insulated steady-state state; the second positive steady-state voltage to ground is the voltage of the positive electrode relative to the preset ground terminal when only the target detection switch is closed and the energy storage device is in an insulated steady-state state; the second negative steady-state voltage to ground is the voltage of the negative electrode relative to the preset ground terminal when only the target detection switch is closed and the energy storage device is in an insulated steady-state state.

[0087] S104: Estimate the insulation resistance of the energy storage device based on the positive steady-state voltage to ground and the negative steady-state voltage to ground.

[0088] The insulation resistance of the energy storage device is estimated by: determining a first positive equivalent resistance to ground and a first negative equivalent resistance to ground when the first detection switch and the second detection switch are closed at the same time, and determining a second positive equivalent resistance to ground and a second negative equivalent resistance to ground when only the target detection switch is closed; constructing a first equation based on the first positive steady-state voltage to ground, the first negative steady-state voltage to ground, the first positive equivalent resistance to ground, and the first negative equivalent resistance to ground, wherein one side of the first equation is the ratio of the first positive steady-state voltage to ground to the first negative steady-state voltage to ground, and the other side of the first equation is the ratio of the first positive equivalent resistance to ground to the first negative equivalent resistance to ground. a ratio of the second positive steady-state voltage to ground and the second negative steady-state voltage to ground; constructing a second equation based on the second positive steady-state voltage to ground, the second negative steady-state voltage to ground, the second positive equivalent resistance to ground, and the second negative equivalent resistance to ground, wherein one side of the second equation is the ratio of the second positive equivalent resistance to ground and the second negative equivalent resistance to ground; combining the first equation and the second equation to calculate the positive insulation resistance and the negative insulation resistance of the energy storage device; estimating the insulation resistance of the energy storage device based on the comparison result of the positive insulation resistance and the negative insulation resistance to ground.

[0089] That is to say, when the positive half-bridge detection circuit is connected between the positive pole of the energy storage device and the preset ground terminal, the negative half-bridge detection circuit is connected between the negative pole of the energy storage device and the preset ground terminal, and the first detection switch and the second detection switch are closed at the same time, the equivalent resistance between the positive pole of the energy storage device and the preset ground terminal is the first positive equivalent resistance to ground, and the equivalent resistance between the negative pole of the energy storage device and the preset ground terminal is the first negative equivalent resistance to ground; when the positive half-bridge detection circuit is connected between the positive pole of the energy storage device and the preset ground terminal, the negative half-bridge detection circuit is connected between the negative pole of the energy storage device and the preset ground terminal, and only the target detection switch is closed, the equivalent resistance between the positive pole of the energy storage device and the preset ground terminal is the second positive equivalent resistance to ground, and the equivalent resistance between the negative pole of the energy storage device and the preset ground terminal is the second negative equivalent resistance to ground.

[0090] The positive insulation resistance to ground is the insulation resistance between the positive electrode and the preset ground terminal when the energy storage device is in the insulation steady state, and the negative insulation resistance to ground is the insulation resistance between the negative electrode and the preset ground terminal when the energy storage device is in the insulation steady state.

[0091] As shown in Figure 2, the equivalent circuit between the positive electrode of the energy storage device and the preset ground terminal can be understood as the insulation resistance R PIn parallel with the positive equivalent capacitor C1, the equivalent circuit between the negative electrode of the energy storage device and the preset ground terminal can be understood as the negative insulation resistance R N When the first detection switch and the second detection switch are closed at the same time, the first positive-to-ground equivalent resistance is the second resistor and the third resistor in series with the first resistor and the positive-to-ground insulation resistance R P The resistance after parallel connection, that is, the first equivalent resistance to ground is R P / / R1 / / (R2+R3); the first negative equivalent resistance to ground is the fifth resistor and the sixth resistor in series with the fourth resistor and the negative insulation resistance R N The resistance after parallel connection, that is, the first negative equivalent resistance to ground is R N / / R4 / / (R5+R6). When only the first detection switch is closed, the second equivalent resistance to ground is the second resistor and the third resistor connected in series with the first resistor and the insulation resistance to ground R P The resistance after parallel connection, that is, the second equivalent resistance to ground is R P / / R1 / / (R2+R3); the second negative equivalent resistance to ground is the fourth resistance, the negative insulation resistance to ground R N The resistance after parallel connection, that is, the second negative equivalent resistance to ground is R N / / R4.

[0092] When the first detection switch and the second detection switch are closed at the same time, the first positive steady-state voltage to ground is U1, and the first negative steady-state voltage to ground is U2, and the first equation is: When only the first detection switch is closed, the second positive steady-state voltage to ground is U3, and the second negative steady-state voltage to ground is U4, so the second equation is: Since the only unknown quantity is R P and R N , and then after combining the first and second equations, we can solve R P and R N .

[0093] Due to the presence of the positive equivalent capacitor C1 and the negative equivalent capacitor C2, i.e., the Y-capacitor, after the first detection switch and the second detection switch are opened or closed, the voltage between the positive electrode of the energy storage device and the preset ground terminal, and the voltage between the negative electrode of the energy storage device and the preset ground terminal, do not immediately change to a steady-state value. Instead, they gradually approach a stable value over a long period of time. The time required for stabilization increases with increasing insulation resistance and Y-capacitor. Consequently, the method for determining the steady-state voltage across the sampling resistor disclosed herein only requires setting a reasonable sampling period to obtain the detection voltage across the sampling resistor, without having to wait for the detection voltage across the sampling resistor to stabilize before acquiring the stable voltage across the sampling resistor. This shortens the time required to determine the steady-state voltage across the sampling resistor, thereby shortening the time required to determine the steady-state voltage across the sampling resistor and the time required to determine the steady-state voltage between the positive electrode of the energy storage device and the preset ground terminal, and between the negative electrode of the energy storage device and the preset ground terminal, achieving the technical effect of shortening the time required to determine the insulation resistance. Furthermore, because the formula used to determine the steady-state voltage across the sampling resistor takes the Y-capacitor into account, the accuracy of calculating the steady-state voltage is improved.

[0094] In order to collect the appropriate detection voltage, the sampling resistor is usually set to a small resistance, and the resistance of the sampling resistor is generally much smaller than the resistance of other resistors in the sampling circuit. If there is only a positive half-bridge circuit and the first detection switch is closed, due to the positive insulation resistance R P Among the first resistor, the second resistor and the third resistor, only the insulation resistance R P An unknown quantity. After calculating the steady-state voltage of the first sampling resistor by the voltage across the first sampling resistor corresponding to each sampling moment, the voltage between the positive electrode of the energy storage device and the preset ground terminal can be theoretically calculated based on the relationship between the resistors in the circuit. Since there is no insulation, the insulation resistance R between the positive electrode and the ground of the energy storage device in the steady state is P Large, resulting in the flow through the insulation resistance R P The current is too small, which will cause some difficulties in calculation. Then, we can solve R by combining the first and second equations. P and R N .

[0095] Since the smaller the insulation resistance, the higher the safety risk, the larger the leakage current of the energy storage device, and the leakage current of the positive electrode of the energy storage device and the leakage current of the negative electrode of the energy storage device pose the same safety risk to the energy storage device, the minimum value is selected between the positive insulation resistance to ground and the negative insulation resistance to ground, and the minimum value is used as the insulation resistance of the energy storage device. Therefore, when the insulation resistance is less than the preset resistance value, it can be determined that the energy storage device has an insulation fault and the staff needs to be prompted to repair it.

[0096] For example, if the insulation resistance of the energy storage device is less than 500Ω / V, an insulation alarm is issued; if the insulation resistance of the energy storage device is less than 100Ω / V, an insulation fault prompt is issued and the energy storage device cannot be supplied with high voltage.

[0097] Please refer to FIG4 , which is a schematic diagram of an insulation resistance detection circuit provided by an embodiment of the present disclosure. The insulation resistance detection circuit includes:

[0098] A grounding switch Kg is arranged between a preset ground terminal PE of the insulation resistance detection circuit and a local ground terminal GND of the energy storage device;

[0099] A first sampling circuit 30 is arranged between the positive electrode Bat+ of the energy storage device and the preset ground terminal PE. The first sampling circuit includes multiple resistors and collects a first detection voltage of the first sampling resistor at each sampling moment. The first sampling resistor is one of the multiple resistors included in the first sampling circuit.

[0100] A second sampling circuit 40 is arranged between the negative electrode Bat- of the energy storage device and the preset ground terminal PE. The second sampling circuit includes multiple resistors and collects a second detection voltage of the second sampling resistor at each sampling moment. The second sampling resistor is one of the multiple resistors included in the second sampling circuit.

[0101] The processor (not shown in the figure) is used to execute the insulation resistance rapid detection method provided by the above embodiment.

[0102] The first sampling circuit 30 includes a first detection switch K1, a first resistor R1, a second resistor R2, a third resistor R3, and a first voltmeter V1. The first sampling resistor is one of the second resistor and the third resistor. The first resistor is arranged between the positive electrode of the energy storage device and the preset ground terminal. The second resistor, the third resistor, and the first detection switch are connected in series and then connected in parallel with the first resistor. The first voltmeter is connected in parallel across the first sampling resistor. The first voltmeter is connected to the processor to send the first detection voltage collected at each sampling moment to the processor.

[0103] The resistance of the first sampling resistor is smaller than the resistance of the first preset resistor. The resistance of the first sampling resistor is smaller than the resistance of the first resistor. The first preset resistor is the other of the second resistor and the third resistor.

[0104] The second sampling circuit 40 includes a second detection switch K2, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, and a second voltmeter V2. The second sampling resistor is one of the fifth resistor and the sixth resistor. The fourth resistor is arranged between the negative electrode of the energy storage device and the preset ground terminal. The fifth resistor, the sixth resistor, and the second detection switch are connected in series and then in parallel with the fourth resistor. The second voltmeter is connected in parallel at both ends of the second sampling resistor. The second voltmeter is connected to the processor to send the second detection voltage collected at each sampling moment to the processor.

[0105] The resistance of the second sampling resistor is smaller than the resistance of the second preset resistor, the resistance of the second sampling resistor is smaller than the resistance of the fourth resistor, and the second preset resistor is the other of the fifth resistor and the sixth resistor.

[0106] This disclosure considers the impact of the equivalent Y-capacitor in the energy storage device's equivalent circuit to ground. It utilizes limited dynamic voltage data to quickly and accurately predict the steady-state voltage of the corresponding circuit, eliminating the need to wait for the voltage to stabilize. This allows for rapid and accurate detection of the overall insulation resistance of the energy storage device, thereby shortening the insulation test time. Specifically, this disclosure requires only sampling the voltage across each sampling resistor in the insulation resistance detection circuit under two circuit configurations. Setting an appropriate sampling period can significantly reduce insulation test time.

[0107] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the system and device described above can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here. In the several embodiments provided in the present disclosure, it should be understood that the disclosed system, device and method can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation. For example, 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 communication interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0108] 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 network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0109] In addition, each functional unit in each embodiment of the present disclosure may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0110] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a non-volatile computer-readable storage medium that is executable by a processor. Based on this understanding, the technical solution of the present disclosure, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present disclosure. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0111] The above are only specific embodiments of the present disclosure, but the scope of protection of the present disclosure is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this disclosure should be included in the scope of protection of the present disclosure. Therefore, the scope of protection of the present disclosure should be based on the scope of protection of the claims. Industrial Applicability

[0112] The present disclosure provides a method for quickly detecting the insulation resistance of an energy storage device, the method comprising: obtaining multiple first detection voltages and multiple second detection voltages for the energy storage device; determining a first steady-state voltage of the first sampling resistor based on the first detection voltage at multiple sampling moments, and determining a second steady-state voltage of the second sampling resistor based on the second detection voltage at multiple sampling moments; determining a positive steady-state voltage to ground and a negative steady-state voltage to ground of the energy storage device based on the first steady-state voltage and the second steady-state voltage; estimating the insulation resistance of the energy storage device based on the positive steady-state voltage to ground and the negative steady-state voltage to ground. The present disclosure solves the problem in the prior art that the insulation resistance can only be calculated after the sampling voltage stabilizes, which results in a long fault judgment time, and the problem in the prior art that the influence of the Y capacitor of the energy storage device on the insulation resistance detection is not considered, thereby achieving the effect of reducing the detection time and improving the detection accuracy.

[0113] Furthermore, it is understood that the disclosed method for rapidly detecting the insulation resistance of an energy storage device is reproducible and can be used in a variety of industrial applications. For example, the disclosed method for rapidly detecting the insulation resistance of an energy storage device can be used in any application requiring insulation testing of an energy storage device.

Claims

1. A method for quickly detecting the insulation resistance of an energy storage device, characterized in that: The method comprises: Acquire a plurality of first detection voltages and a plurality of second detection voltages for the energy storage device; Determine a first steady-state voltage of the first sampling resistor according to the first detection voltage at multiple sampling moments, and determine a second steady-state voltage of the second sampling resistor according to the second detection voltage at multiple sampling moments; Determining a positive steady-state voltage to ground and a negative steady-state voltage to ground of the energy storage device according to the first steady-state voltage and the second steady-state voltage; The insulation resistance of the energy storage device is estimated based on the positive steady-state voltage to ground and the negative steady-state voltage to ground.

2. The method according to claim 1, characterized in that Each first detection voltage refers to the voltage of the first sampling resistor on the first sampling circuit located between the positive electrode of the energy storage device and the preset ground terminal at each sampling moment, and each second detection voltage refers to the voltage of the second sampling resistor on the second sampling circuit located between the negative electrode of the energy storage device and the preset ground terminal at each sampling moment.

3. The method according to claim 2, characterized in that The first sampling circuit is a positive half-bridge sampling circuit, and the second sampling circuit is a negative half-bridge sampling circuit.

4. The method according to claim 2, characterized in that: The positive steady-state voltage to ground refers to the voltage of the positive electrode of the energy storage device relative to the preset ground terminal when it is in an insulating steady-state state, and the negative steady-state voltage to ground refers to the voltage of the negative electrode of the energy storage device relative to the preset ground terminal when it is in an insulating steady-state state.

5. The method according to claim 1, characterized in that The steady-state voltage is determined based on a resistor-capacitor charge-discharge time formula, which is used to characterize the relationship between the detection voltage and the steady-state voltage, wherein the detection voltage is equal to the sum of the steady-state voltage and an exponential term, wherein the exponential term includes the product of a coefficient and a natural exponential term with respect to time.

6. The method according to claim 5, characterized in that The steady-state voltage is determined in the following manner: based on the resistor-capacitor charge-discharge time formula, a plurality of sampling moments and their corresponding detection voltages are used to obtain the steady-state voltage.

7. The method according to claim 1, characterized in that The steady-state voltage is determined by: Based on a linear formula, a constant term and a slope of the linear formula are obtained by using a plurality of sampling moments and their corresponding detection voltages, wherein the independent variable of the linear formula is the sampling moment and the dependent variable is the detection voltage; Based on the constant term and the slope of the linear formula, determine the exponential term in the resistor and capacitor charge and discharge time formula, wherein the resistor and capacitor charge and discharge time formula is used to characterize the relationship between the detection voltage and the steady-state voltage, wherein the detection voltage is equal to the sum of the steady-state voltage and the exponential term; Based on the resistor-capacitor charge-discharge time formula, a steady-state voltage is obtained by using any sampling time and its corresponding detection voltage.

8. The method according to claim 2, characterized in that: The first sampling circuit includes a first resistor, a second resistor and a third resistor, wherein the first resistor is arranged between the positive electrode of the energy storage device and the preset ground terminal, the second resistor and the third resistor are connected in series and then connected in parallel with the first resistor, and the first sampling resistor is one of the second resistor and the third resistor. And / or, the second sampling circuit includes a fourth resistor, a fifth resistor and a sixth resistor, wherein the fourth resistor is arranged between the negative electrode of the energy storage device and the preset ground terminal, the fifth resistor and the sixth resistor are connected in series and connected in parallel with the fourth resistor, and the second sampling resistor is one of the fifth resistor and the sixth resistor.

9. The method according to claim 8, characterized in that The first sampling circuit further includes a first detection switch disposed on a branch where the second resistor and the third resistor are connected in series, and the second sampling circuit further includes a second detection switch disposed on a branch where the fifth resistor and the sixth resistor are connected in series.

10. The method according to claim 9, characterized in that The multiple first detection voltages include a voltage of the first sampling resistor collected when only the first detection switch is closed, and / or a voltage of the first sampling resistor collected when the first detection switch and the second detection switch are closed at the same time. The plurality of second detection voltages include a voltage of the second sampling resistor collected when only the second detection switch is closed, and / or a voltage of the second sampling resistor collected when the first detection switch and the second detection switch are closed simultaneously.

11. The method according to claim 10, characterized in that The obtaining of a plurality of first detection voltages and a plurality of second detection voltages for the energy storage device comprises: Determining a positive ground-referenced steady-state voltage and a negative ground-referenced steady-state voltage of the energy storage device when the first detection switch and the second detection switch are closed simultaneously; Determining a target detection switch according to a comparison result between a positive reference steady-state voltage to ground and a negative reference steady-state voltage to ground, wherein the target detection switch is one of the first detection switch and the second detection switch; The voltage of the sampling resistor corresponding to when only the target detection switch is closed, and the voltage of the first sampling resistor and the voltage corresponding to the second sampling resistor when the first detection switch and the second detection switch are closed at the same time are determined as multiple first detection voltages and multiple second detection voltages for the energy storage device.

12. The method according to claim 11, characterized in that The positive steady-state voltage to ground of the energy storage device includes a first positive steady-state voltage to ground and a second positive steady-state voltage to ground, and the negative steady-state voltage to ground includes a first negative steady-state voltage to ground and a second negative steady-state voltage to ground. The first positive steady-state voltage to ground is determined according to a voltage corresponding to the first sampling resistor when the first detection switch and the second detection switch are closed at the same time, and the first negative steady-state voltage to ground is determined according to a voltage corresponding to the second sampling resistor when the first detection switch and the second detection switch are closed at the same time. The first target steady-state voltage is determined according to the voltage of the sampling resistor corresponding to when only the target detection switch is closed, the second target steady-state voltage is determined according to the voltage between the positive and negative electrodes of the energy storage device and the first target steady-state voltage, the first target steady-state voltage is one of the second positive steady-state voltage to ground and the second negative steady-state voltage to ground, and the second target steady-state voltage is The voltage is the other of a second positive steady-state voltage to ground and a second negative steady-state voltage to ground.

13. The method according to claim 12, characterized in that The insulation resistance of the energy storage device is estimated by: Determine a first positive equivalent resistance to ground and a first negative equivalent resistance to ground when the first detection switch and the second detection switch are closed simultaneously, and determine a second positive equivalent resistance to ground and a second negative equivalent resistance to ground when only the target detection switch is closed; constructing a first equation according to the first positive steady-state voltage to ground, the first negative steady-state voltage to ground, the first positive equivalent resistance to ground, and the first negative equivalent resistance to ground, wherein one side of the first equation is a ratio of the first positive steady-state voltage to ground to the first negative steady-state voltage to ground, and the other side of the first equation is a ratio of the first positive equivalent resistance to ground to the first negative equivalent resistance to ground; constructing a second equation according to the second positive steady-state voltage to ground, the second negative steady-state voltage to ground, the second positive equivalent resistance to ground, and the second negative equivalent resistance to ground, wherein one side of the second equation is a ratio of the second positive steady-state voltage to ground to the second negative steady-state voltage to ground, and the other side of the second equation is a ratio of the second positive equivalent resistance to ground to the second negative equivalent resistance to ground; Combining the first equation and the second equation, calculating the positive insulation resistance to ground and the negative insulation resistance to ground of the energy storage device; The insulation resistance of the energy storage device is estimated based on the comparison result of the positive insulation resistance to ground and the negative insulation resistance to ground.

14. An insulation resistance detection circuit, characterized in that: The insulation resistance detection circuit comprises: A grounding switch is arranged between a preset grounding terminal of the insulation resistance detection circuit and a local grounding terminal of the energy storage device; A first sampling circuit is arranged between the positive electrode of the energy storage device and the preset ground terminal, the first sampling circuit includes a plurality of resistors, and a first detection voltage of the first sampling resistor is collected at each sampling moment, the first sampling resistor is one of the plurality of resistors included in the first sampling circuit; A second sampling circuit is arranged between the negative electrode of the energy storage device and the preset ground terminal, the second sampling circuit includes a plurality of resistors, and a second detection voltage of the second sampling resistor is collected at each sampling moment, and the second sampling resistor is one of the plurality of resistors included in the second sampling circuit; A processor, configured to execute the insulation resistance rapid detection method as claimed in any one of claims 1 to 13.

15. The circuit according to claim 14, characterized in that The first sampling circuit includes: a first detection switch, a first resistor, a second resistor, a third resistor, and a first voltmeter, wherein the first sampling resistor is one of the second resistor and the third resistor. The first resistor is arranged between the positive electrode of the energy storage device and the preset ground terminal, the second resistor, the third resistor and the first detection switch are connected in series and then connected in parallel with the first resistor, and the first voltmeter is connected in parallel with the first sampling switch. The two ends of the resistor, The first voltmeter is connected to the processor to send the first detection voltage collected at each sampling moment to the processor.

16. The circuit according to claim 14, characterized in that The second sampling circuit includes: a second detection switch, a fourth resistor, a fifth resistor, a sixth resistor, and a second voltmeter, wherein the second sampling resistor is one of the fifth resistor and the sixth resistor. The fourth resistor is arranged between the negative electrode of the energy storage device and the preset ground terminal, the fifth resistor, the sixth resistor and the second detection switch are connected in series and then connected in parallel with the fourth resistor, and the second voltmeter is connected in parallel at both ends of the second sampling resistor. The second voltmeter is connected to the processor to send the second detection voltage collected at each sampling moment to the processor.

17. The circuit according to claim 15, characterized in that The resistance of the first sampling resistor is smaller than the resistance of the first preset resistor. The resistance of the first sampling resistor is smaller than the resistance of the first resistor. The first preset resistor is the other of the second resistor and the third resistor.

18. The circuit according to claim 16, characterized in that The resistance of the second sampling resistor is smaller than the resistance of the second preset resistor, the resistance of the second sampling resistor is smaller than the resistance of the fourth resistor, and the second preset resistor is the other of the fifth resistor and the sixth resistor.

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