Insulation sampling circuit, control method thereof, withstand voltage test method, and power consumption device

Abstract

An isolated sampling circuit, a control method thereof, a withstand voltage test method, and a power consuming device are provided. The isolated sampling circuit includes a first sampling circuit (100) including a first sampling module (120), a first resistor (R1) and a first switch module (110), a second sampling circuit (200) including a second sampling module (220), a second resistor (R2) and a second switch module (210), and a withstand voltage module (300). The first resistor (R1) is connected in parallel to the first sampling module (120), and the first switch module (110) is used to control the first sampling module (120) and / or the first resistor (R1) to be connected between the positive bus (P+) and the ground wire (GND); the second resistor (R2) is connected in parallel to the second sampling module (220), and the second switch module (210) is used to control the second sampling module (220) and / or the second resistor (R2) to be connected between the negative bus (P-) and the ground wire (GND); and the voltage resistance module (300) is installed in the ground wire (GND) to cut off the ground wire (GND), which can effectively improve the voltage resistance capability between the positive bus (P+) and the ground wire (GND) / between the negative bus (P-) and the ground wire (GND) and meet the demand for high-voltage voltage resistance testing.

Description

Technical Field

[0001] (Cross - reference to related applications) This application claims the priority of Chinese Patent Application No. 202111306494.2, titled "Insulation Sampling Circuit, Its Control Method, Dielectric Withstand Test Method and Power - consuming Equipment", filed on November 05, 2021, and all the contents of the said application are incorporated herein by reference.

[0002] This application relates to the field of insulation detection. Specifically, it relates to an insulation sampling circuit, its control method, dielectric withstand test method and power - consuming equipment.

Background Art

[0003] Insulation detection is a method used in various scenarios such as electric vehicles, hybrid vehicles, and charging piles to detect the insulation resistance between the high - voltage positive electrode and the ground, and between the high - voltage negative electrode and the ground, and to judge the insulation performance. This is used to ensure electrical safety and avoid direct human injury caused by high voltage. However, the current insulation detection circuit cannot solve the problem that the dielectric withstand ability of the sampling circuit is limited.

Summary of the Invention

[0004] In view of the above problems, this application provides an insulation sampling circuit, its control method, dielectric withstand test method and power - consuming equipment that can solve the problem that the dielectric withstand ability of the sampling circuit for insulation detection is limited.

[0005] According to the first aspect, the present application provides an insulation sampling circuit. This insulation sampling circuit includes a first sampling circuit, a second sampling circuit, and a withstand voltage module. The first sampling circuit includes a first sampling module, a first resistor, and a first switch module. The first resistor is connected in parallel with the first sampling module. The first switch module is used to control the connection of the first sampling module and / or the first resistor between the positive bus and the ground wire. The second sampling circuit includes a second sampling module, a second resistor, and a second switch module. The second resistor is connected in parallel with the second sampling module. The second switch module is used to control the connection of the second sampling module and / or the second resistor between the negative bus and the ground wire. The withstand voltage module is installed on the ground wire and is used to cut off the ground wire.

[0006] In the technical solution of the embodiment of the present application, by adding a withstand voltage module that can keep the ground wire cut off to the ground wire, the withstand voltage ability between the positive bus and the ground wire / between the negative bus and the ground wire can be effectively improved, and the demand for a high-voltage withstand voltage test can be satisfied. And by installing a withstand voltage module on the ground wire, it is also helpful for detecting the actual operating state of the withstand voltage module, and different test requirements can be reconciled and satisfied.

[0007] In some embodiments, the first switch module includes a first switch and a third switch, and the second switch module includes a second switch and a fourth switch. One end of the first resistor is connected to the positive busbar, the other end of the first resistor is connected to the ground wire by the first switch, one end of the first sampling module is connected to the positive busbar, and the other end of the first sampling module is connected to the ground wire by the third switch. One end of the second resistor is connected to the positive busbar, the other end of the second resistor is connected to the ground wire by the second switch, one end of the second sampling module is connected to the positive busbar, and the other end of the second sampling module is connected to the ground wire by the fourth switch. The switch modules in the embodiments of the present application are composed of two switches that independently control whether each is connected to a sampling module and a known resistor to realize different detection steps.

[0008] In some embodiments, the first sampling module includes a third resistor and a fifth resistor, and the second sampling module includes a fourth resistor and a sixth resistor. One end of the third resistor is connected to the positive busbar, the other end of the third resistor is connected to one end of the fifth resistor, the other end of the fifth resistor is connected to the ground wire by the third switch, and the connection node between the third resistor and the fifth resistor forms a first voltage sampling point. One end of the fourth resistor is connected to the negative busbar, the other end of the fourth resistor is connected to one end of the sixth resistor, the other end of the sixth resistor is connected to the ground wire by the fourth switch, and the connection node between the fourth resistor and the sixth resistor forms a second voltage sampling point. The embodiments of the present application provide a sampling module composed of two series resistors, and the requirements of the actual application situation can be met by adjusting the resistance values of the resistors.

[0009] In some embodiments, the withstand voltage module includes a controllable switch installed on the ground wire. With such a design, the ground wire can be disconnected when necessary to provide a high withstand voltage capacity and meet the requirements of the withstand voltage test. After the withstand voltage test is completed, the ground wire can be reconnected to meet the requirements of the insulation test.

[0010] According to a second aspect, the present application provides a withstand voltage test method. This withstand voltage test method is used in the insulation sampling circuit as described above. This withstand voltage test method may include applying a preset voltage between the positive busbar and the ground wire connected to the insulation sampling circuit, and applying a preset voltage between the negative busbar and the ground wire connected to the insulation sampling circuit. The withstand voltage module of the insulation sampling circuit keeps the ground wire disconnected.

[0011] In the technical solution of the embodiments of the present application, in addition to the switch module, a withstand voltage module for disconnecting the ground wire is also installed between the positive busbar and the ground wire / between the negative busbar and the ground wire. Thereby, the insulation sampling circuit has a high withstand voltage capacity and can complete a high-voltage withstand voltage test.

[0012] According to a third aspect, the present application provides a control method for the insulation sampling circuit as described above. This control method includes controlling the withstand voltage module of the insulation sampling circuit to be connected to the ground wire, controlling the first switch module of the insulation sampling circuit to connect the first sampling module between the positive busbar and the ground wire, and controlling the second switch module to connect the second sampling module between the negative busbar and the ground wire, obtaining the second sampling voltage formed by the second sampling module, judging whether the ground wire is conductive according to the change trend of the second sampling voltage, performing insulation detection when the ground wire is conductive, and outputting fault information when the ground wire is disconnected.

[0013] In the technical solution of the embodiment of the present application, by detecting and determining whether the ground wire is conducting according to the change trend of the detected sampling voltage, it is possible to detect and determine the situation where the withstand voltage module fails or becomes invalid, and improve the reliability of the insulation detection result.

[0014] In some embodiments, determining whether the ground wire is conducting according to the change trend of the second sampling voltage specifically includes: obtaining the elapsed time from when the withstand voltage module is connected to the ground wire until the second sampling voltage becomes stable; determining whether the elapsed time meets a preset time threshold, and if it meets, determining that the ground wire is conducting. Such a design can ensure the accuracy of the insulation detection result by detecting whether the withstand voltage module is normally connected to the ground wire by utilizing the charging process of a capacitor (for example, this capacitor may be a capacitor in the body of a new energy vehicle equipped with a high-voltage battery system) that usually exists when the ground wire is conducting.

[0015] In some embodiments, before controlling the withstand voltage module to be connected to the ground wire, the method includes connecting a first sampling module of the insulation sampling circuit and a first resistor between the positive electrode bus and the ground wire, and connecting a second sampling module and a second resistor between the negative electrode bus and the ground wire; obtaining a voltage signal formed by the first sampling module or the second sampling module; determining whether there is a fault in the first sampling circuit and the second sampling circuit based on the voltage signal; outputting fault information if there is a fault; and if there is no fault, controlling the withstand voltage module to be connected to the ground wire, controlling a first switch module to disconnect the first resistor from between the positive electrode bus and the ground wire, and controlling a second switch module to disconnect the second resistor from between the negative electrode bus and the ground wire. Such a design ensures that the sampling circuit is in a normal operating state by setting an additional detection program before insulation detection.

[0016] In some embodiments, determining whether there is a fault in the first sampling circuit and the second sampling circuit based on the voltage signal specifically includes calculating a theoretical voltage difference between the positive electrode bus and the negative electrode bus based on the voltage signal; calculating a difference value between the theoretical voltage difference and the actual voltage difference between the positive electrode bus and the negative electrode bus; determining whether an absolute value of the difference value between the theoretical voltage difference and the actual voltage difference is smaller than a preset difference threshold value compared to the actual voltage difference; if so, determining that there is no fault in the first sampling circuit and the second sampling circuit; and if not, determining that there is a fault in the first sampling circuit and the second sampling circuit.

[0017] In the technical solution of the embodiment of the present application, after estimating the theoretical voltage between the positive bus bar and the negative bus bar according to the sampled voltage signal, it is designed to determine whether there is a fault in the first sampling circuit and the second sampling circuit according to the magnitude of the difference between the theoretical voltage estimated according to the sampling result and the actual voltage, thereby improving the reliability of insulation detection.

[0018] In some embodiments, when the grounding wire is conductive, performing insulation detection specifically includes: respectively obtaining a first sampling voltage formed by a first sampling module and a second sampling voltage formed by a second sampling module; when the first sampling voltage is greater than or equal to the second sampling voltage, controlling to connect the first resistor between the positive bus bar and the grounding wire; after the first resistor is connected, obtaining a third sampling voltage formed by the first sampling module and a fourth sampling voltage formed by the second sampling module; calculating a first insulation resistance between the positive bus bar and the grounding wire and a second insulation resistance between the negative bus bar and the grounding wire based on the first sampling voltage, the second sampling voltage, the third sampling voltage, and the fourth sampling voltage; when the first sampling voltage is less than the second sampling voltage, controlling to connect the second resistor between the negative bus bar and the grounding wire; after the second resistor is connected, obtaining a fifth sampling voltage formed by the first sampling module and a sixth sampling voltage formed by the second sampling module; calculating a first insulation resistance between the positive bus bar and the grounding wire and a second insulation resistance between the negative bus bar and the grounding wire based on the first sampling voltage, the second sampling voltage, the fifth sampling voltage, and the sixth sampling voltage.

[0019] In the technical solution of the embodiment of the present application, insulation detection is performed by correspondingly controlling the connection of the first resistor or the second resistor according to the magnitudes of the first sampling voltage and the second sampling voltage, so as to reduce errors and calculate and obtain a more accurate insulation resistance.

[0020] According to a fourth aspect, the present application provides a control device for an insulation sampling circuit as described above. This control device controls the withstand voltage module of the insulation sampling circuit to be connected to the ground wire, controls the first switch module of the insulation sampling circuit to connect the first sampling module between the positive bus and the ground wire, and controls the second switch module to connect the second sampling module between the negative bus and the ground wire. It includes a switch control unit, a ground wire detection unit for obtaining the second sampling voltage formed by the second sampling module and determining whether the ground wire is conducting according to the change trend of the second sampling voltage, an insulation detection unit for performing insulation detection when the ground wire is conducting, and a fault reporting unit for outputting fault information when the ground wire is disconnected.

[0021] In the technical solution of the embodiment of the present application, by controlling the withstand voltage module, the ground wire can be made conducting to be suitable for insulation detection, and according to the change trend of the sampling voltage, it can be detected and determined whether the ground wire is really conducting.

[0022] According to a fifth aspect, the present application provides a battery management system. This battery management system includes an insulation sampling circuit, a processor, and a memory as described above. A computer program instruction is stored in the memory, and when the computer program instruction is called by the processor, the processor is caused to execute the control method as described above.

[0023] In the technical solution of the embodiment of the present application, after the withstand voltage test is completed, the battery management system can control the withstand voltage module to conduct the ground wire so as to be suitable for insulation detection. In addition, according to the change trend of the sampling voltage, it is also possible to detect and determine whether the ground wire is really conducting.

[0024] According to a sixth aspect, the present application provides an electric power consuming device. This electric power consuming device includes a battery, a load, and a battery management system as described above. The battery is connected to the battery management system and supplies power to the load.

[0025] In the technical solution of the embodiment of the present application, the battery management system of the electric power consuming device has a high withstand voltage ability. After the withstand voltage test is completed, by controlling the withstand voltage module, the ground wire can be conducted so as to be suitable for insulation detection, and it can also detect whether the ground wire is really conducting, ensuring the accuracy of the insulation detection result.

[0026] According to a seventh aspect, the present application provides a computer storage medium. Here, a computer program instruction is stored in the computer storage medium, and when the computer program instruction is called by a processor, the processor is caused to execute the control method as described above.

[0027] In the technical solution of the embodiment of the present application, this computer storage medium can be installed in an electronic device such as a battery management system. Thereby, after the withstand voltage test is completed, by controlling the withstand voltage module, the ground wire can be conducted so as to be suitable for insulation detection, and it can also detect whether the ground wire is really conducting.

[0028] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, be able to implement based on the content of the specification, and make the above and other objects, features, and advantages of the present application clearer and easier to understand, the following specific embodiments of the present application are given.

Brief Description of the Drawings

[0029] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become apparent to those skilled in the art. The drawings are used only to illustrate the preferred embodiments and are not considered to limit the present application. Throughout the drawings, the same parts are denoted by the same reference numerals.

Figure 1a

Figure 1b

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10a

Figure 10b

Figure 10c

Figure 10d

Figure 10e

Figure 11

Figure 12

Figure 13

Embodiments for Carrying Out the Invention

[0030] Hereinafter, embodiments of the technical solution of the present application will be described in detail with reference to the drawings. The following embodiments are for more clearly explaining the technical solution of the present application and are merely illustrative, and the protection scope of the present application is not limited thereby.

[0031] Unless otherwise defined, all technical and scientific terms used in this document shall have the same meaning as commonly understood by those skilled in the art to which this application pertains. The terms used in this specification are only for the purpose of describing specific embodiments and are not intended to limit this application. In the description of the specification, claims, and drawings of this application, the terms "include", "have", and any variations thereof are intended to cover the non-exclusive "include".

[0032] In the description of the embodiments of this application, technical terms such as "first", "second", etc. are only used for the purpose of distinguishing different objects and are not understood to explicitly or implicitly indicate relative importance, or the number of indicated technical features, a specific order, or a primary-secondary relationship. In the description of the embodiments of this application, unless specifically limited, "a plurality" means two or more.

[0033] The "embodiments" referred to in this specification mean that the specific features, structures, or characteristics described in connection with the embodiments may be included in at least one embodiment of this application. The appearance of this phrase at each position in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art can explicitly and implicitly understand that the embodiments described in this specification can be combined with other embodiments.

[0034] In the description of the embodiments of this application, the term "and / or" is only used to explain the relationship between related objects and represents that three relationships may exist. For example, A and / or B may represent three cases: A alone, the combination of A and B, and B alone. Also, the character " / " in this document generally represents that the related objects before and after are in an "or" relationship.

[0035] In the description of the embodiments of this application, the term "a plurality" refers to two or more (including two), and similarly, "a plurality of groups" refers to two or more groups (including two groups), and "a plurality of pieces" refers to two or more pieces (including two pieces).

[0036] In the description of the embodiments of the present application, with respect to the orientation or positional relationship indicated by terms such as the technical terms "center", "vertical direction", "horizontal direction", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial direction", "radial direction", "circumferential direction", etc., it is based on the orientation or positional relationship shown in the drawings and is for the convenience of the description of the embodiments of the present application or for the purpose of simplifying the description. It does not indicate or imply that the mentioned device or element needs to have a specific orientation and be configured and operated in a specific orientation, and should not be understood as limiting the embodiments of the present application.

[0037] In the description of the embodiments of the present application, unless otherwise specifically defined or limited, terms such as the technical terms "mount", "connect", "connect", "fix", etc. should be understood in a broad sense. For example, it may be a fixed connection, a removable connection, or an integral one, a mechanical connection, an electrical connection, a direct connection, an indirect connection through an intermediate medium, or the internal communication of both elements or the interaction relationship between both elements. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present application according to the specific situation.

[0038] Currently, a high-voltage battery system needs to perform insulation detection during use to prevent direct harm to the human body caused by high voltage. The method of insulation detection is to calculate the insulation resistance between the high-voltage positive electrode and the ground and between the high-voltage negative electrode and the ground by controlling the connection of a known resistance with a relay, a controllable switch, or other types of electronic switches.

[0039] Referring to FIG. 1a, FIG. 1a is a schematic diagram of an insulation sampling circuit according to an embodiment of the present application.

[0040] This is mainly composed of a first sampling circuit 100 and a second sampling circuit 200 connected to the battery positive busbar and the battery negative busbar. The battery management system can connect a resistor with a known resistance (the first resistor R1 or the second resistor R2) by controlling the switch to be turned on, and then calculate the insulation resistance between the high voltage positive electrode and the high voltage negative electrode and the ground (represented by the resistors Rp and Rn in FIG. 1a, respectively) by formulating simultaneous equations based on the sampled voltages obtained before and after connecting the resistors.

[0041] In addition to insulation detection, high-voltage battery systems generally need to undergo one voltage withstand test before shipment. During this voltage withstand test, a high voltage is applied between the positive bus P+ and ground / negative bus P- and ground GND.

[0042] As can be seen, in the isolated sampling circuit shown in FIG. 1a, the voltage applied during the withstand voltage test must not exceed the withstand voltage value of the switch (e.g., switch S3 or switch S4) used in the isolated sampling circuit. In order to meet the requirements of the withstand voltage test, a switch with a high withstand voltage value may be selected. However, the withstand voltage value of the switch has a certain upper limit (e.g., the withstand voltage limit of the photocoupler drive MOS transistor is generally 1600V). Therefore, once the withstand voltage upper limit of the commonly used switch is reached, it is difficult to continue to meet the withstand voltage test of a higher voltage.

[0043] Referring to Fig. 1b, Fig. 1b is a schematic diagram of an isolated sampling circuit according to an embodiment of the present application. Compared with the isolated sampling circuit shown in Fig. 1a, a switch S+ and a switch S- are added to the positive bus P+ and the negative bus P-, respectively. When performing a withstand voltage test, the switch S+ and the switch S- are kept disconnected, thereby improving the withstand voltage capability of the isolated sampling circuit.

[0044] However, through research, the applicant has found that since there is a capacitor between the positive electrode busbar and the ground / negative electrode busbar and the ground (for example, the capacitor in the main body of a new energy vehicle equipped with a high-voltage battery system), it is possible to realize the detection of the withstand voltage module according to the trend of the sampling voltage formed by the sampling circuit. Thus, by adjusting the switch to be installed on the grounding wire and disconnecting the grounding wire, the effect of improving the withstand voltage capacity of the circuit can be achieved.

[0045] For the method of installing switches on the positive and negative electrode busbars shown in FIG. 1b, when installing a withstand voltage device on the grounding wire, only one switch needs to be used, and the number of switches used can be reduced.

[0046] Reducing the number of switches can, on the one hand, reduce the material cost. On the other hand, since the switch, as an electronic device, always has a certain probability of failure, reducing the number of switches can also reduce the probability of switch failure and improve the reliability of the circuit.

[0047] The battery management system disclosed in the embodiments of the present application may be used in power-consuming devices such as vehicles, ships, or aircraft, but is not limited thereto. This power-consuming device includes a load that consumes electrical energy, a battery that supplies power to the load, an insulation sampling circuit for performing voltage sampling, and a battery management system for managing the battery. During operation, the battery management system disclosed in the embodiments of the present application controls the insulation sampling circuit to perform insulation detection on the power-consuming device during the normal use process, thereby determining the insulation status of the power-consuming device.

[0048] The following embodiments will be described by taking, for the sake of convenience of explanation, the power-consuming device of an embodiment of the present application being a vehicle 10 as an example. Referring to FIG. 2, FIG. 2 is a schematic structural diagram of a vehicle 10 according to some embodiments of the present application.

[0049] The vehicle 10 may be a fuel oil vehicle, a gas vehicle, or a new energy vehicle. The new energy vehicle may be a secondary battery electric vehicle, a hybrid electric vehicle, an extended-range electric vehicle, etc. A battery 11 is installed inside the vehicle 10, and the battery 11 may be installed at the bottom, front, or rear of the vehicle 10. The battery 11 may be used to supply power to the vehicle 10. For example, the battery 11 may be used as the operating power supply of the vehicle 10. The vehicle 10 may further include a controller 12 and a motor 13. The controller 12 is for controlling the battery 11 to supply power to the motor 13 and, for example, to be used for the starting, navigation, and operating power requirements during driving of the vehicle 10.

[0050] In some embodiments of the present application, the battery 11 can not only be used as the operating power supply of the vehicle 10, but also be used as the driving power supply of the vehicle 10 to provide driving power to the vehicle 10 instead of, or partly instead of, fuel oil or natural gas.

[0051] The battery 11 refers to any type of energy storage assembly for storing electrical energy. For example, it may be a single battery cell, a battery module composed of a plurality of battery cells, or a battery pack including one or more battery modules. The outer shape of the battery 11 may have a corresponding shape according to the needs of the actual situation, such as a cylindrical body, a rectangular parallelepiped, etc.

[0052] In some embodiments, the connection between the plurality of battery cells in the battery module may be a series connection, a parallel connection, or a series-parallel connection. The series-parallel connection means that it includes both series connection and parallel connection of the plurality of battery cells. The connection between the battery modules constituting the battery pack may also be a series connection, a parallel connection, or a series-parallel connection. The battery pack or the battery module may further include other structures other than the battery cells, such as bus bar components for realizing electrical connection between the plurality of battery cells.

[0053] The controller 12 includes at least one battery management system. This battery management system refers to an electronic system for managing the battery 11 and ensuring its normal operation. The battery management system may further be connected to an insulation sampling circuit, and determine the insulation resistance between the high-voltage positive electrode of the battery and the body ground of the vehicle / between the high-voltage negative electrode and the body ground of the vehicle according to the sampling signal formed by the insulation sampling circuit.

[0054] Before the battery is shipped, the insulation sampling circuit is in a state where the ground wire is disconnected and has a high withstand voltage capacity to support the withstand voltage test. After the withstand voltage test is completed, the insulation sampling circuit is switched to a state where the ground wire is conductive, and under the control of the battery management system, insulation detection is performed on the insulation situation between the high-voltage positive electrode / high-voltage negative electrode of the battery 11 and the body ground, thereby ensuring the personal safety of vehicle users.

[0055] According to some embodiments of the present application, referring to FIG. 3, FIG. 3 is a schematic structural diagram of an insulation sampling circuit according to an embodiment of the present application. There is a first insulation resistance Rp and a capacitor C between the positive electrode bus P+ and the ground GND, and a second insulation resistance Rn and a capacitor C between the negative electrode bus P- and the ground GND. This insulation sampling circuit includes a first sampling circuit 100, a second sampling circuit 200, and a withstand voltage module 300.

[0056] Here, the first sampling circuit 100 includes a first switch module 110, a first resistor R1, and a first sampling module 120. This first sampling circuit 100 is a sampling circuit connected between the positive bus P+ and the ground GND. This controls whether the first sampling module 120 and / or the first resistor R1 are connected between the positive bus P+ and the ground GND by the first switch module 110. The second sampling circuit 200 includes a second switch module 210, a second resistor R2, and a second sampling module 220. This second sampling circuit 200 is a sampling circuit connected between the negative bus P− and the ground wire. This similarly controls whether the second sampling module 220 and / or the second resistor R2 are connected between the negative bus P− and the ground GND by the second switch module 210.

[0057] There is a parallel connection relationship between the first sampling module 120 and the first resistor R1. There is also a parallel connection relationship between the second sampling module 220 and the second resistor R2. The first sampling module 120 and the second sampling module 220 are functional modules that form voltage sampling points. The battery management system can correspondingly obtain the voltage signals collected and acquired by the first sampling circuit and the second sampling circuit by being connected to the voltage sampling points of the first and second sampling modules. Both the first resistor R1 and the second resistor R2 are external resistors with known resistance values. The battery management system can complete the insulation detection process by controlling the switch module to connect or disconnect the first resistor R1 and the second resistor R2.

[0058] This withstand voltage module 300 is installed on the ground wire and is a component between the first / second sampling circuits and the ground end of the ground wire. This achieves the effect of improving the withstand voltage ability of the insulation sampling circuit by means of a component that cuts the ground wire. Specifically, the withstand voltage module 300 may use any suitable type of device as long as it can cut the ground wire to improve the withstand voltage and has the ability to reconnect the ground wire.

[0059] In some embodiments, this withstand voltage module 300 may be a device with the ability to turn on only once. Its initial state is disconnected, and once triggered and switched to the connected state, it becomes irreparable.

[0060] In the actual use process, by keeping the withstand voltage module 300 in the deactivated state and cutting the ground wire, the insulation sampling circuit has a high withstand voltage ability and can complete a high-voltage withstand voltage test. After the withstand voltage test is completed, it is switched to the connected state and insulation detection is performed under the control of the battery management system.

[0061] It should be noted that the above "first" and "second" are only for distinguishing and explaining that the connection positions of the functional modules are different, and are not for limiting specific functional modules. The first sampling circuit and the second sampling circuit may use the same circuit structure design, or may use different circuit structure designs according to the requirements of the actual situation.

[0062] One merit of the insulation sampling circuit according to the embodiments of the present application is that by simply adding one withstand voltage module for cutting the ground wire, the withstand voltage ability between the positive busbar and the ground wire / between the negative busbar and the ground wire can be effectively improved, and the requirement for a high-voltage withstand voltage test can be satisfied.

[0063] According to some embodiments of the present application, continuing to refer to FIG. 3, this first switch module 110 includes a first switch S1 and a third switch S3. This second switch module 210 includes a second switch S2 and a fourth switch S4.

[0064] Here, one end of the first resistor R1 is connected to the positive busbar P+, and the other end of the first resistor R1 is connected to the ground GND by the first switch S1. One end of the first sampling module 120 is connected to the positive busbar P+, and the other end of the first sampling module 120 is connected to the ground GND by the third switch S3.

[0065] Thereby, the battery management system can independently control whether to connect the first resistor R1 and the first sampling module 120 to the detection circuit (i.e., between the positive busbar P+ and the ground GND) by controlling the on / off of the first switch S1 and the third switch S3.

[0066] One end of the second resistor R2 is connected to the negative busbar P-, and the other end of the second resistor R2 is connected to the ground GND by the second switch S2. One end of the second sampling module 220 is connected to the negative busbar P-, and the other end of the second sampling module 220 is connected to the ground GND by the fourth switch S4.

[0067] Thereby, the battery management system can independently control whether to connect the second resistor R2 and the second sampling module 220 to the detection circuit (i.e., between the negative busbar P- and the ground GND) by controlling the on / off of the second switch S2 and the fourth switch S4.

[0068] The switch module of the embodiment of the present application is composed of two switches that independently control whether to connect the sampling module and the external resistor to the detection circuit to realize different detection steps.

[0069] According to some embodiments of the present application, continuing to refer to FIG. 3, this first sampling module 120 includes a third resistor R3 and a fifth resistor R5. The second sampling module 220 includes a fourth resistor R4 and a sixth resistor R6.

[0070] Here, one end of the third resistor R3 is connected to the positive busbar P+, and the other end of the third resistor R3 is connected to one end of the fifth resistor R5. The other end of the fifth resistor R5 is connected to the ground GND by the third switch S3.

[0071] Thereby, the connection node between the third resistor R3 and the fifth resistor R5 connected in series forms a first voltage sampling point P1. By connecting to the first voltage sampling point P1, the battery management system can acquire the voltage signal of the first sampling circuit and perform corresponding data processing.

[0072] Also, one end of the fourth resistor R4 is connected to the negative busbar P-, and the other end of the fourth resistor R4 is connected to one end of the sixth resistor R6. The other end of the sixth resistor R6 is connected to the ground GND by the fourth switch S4.

[0073] Thereby, the connection node between the fourth resistor R4 and the sixth resistor R6 connected in series forms a second voltage sampling point P2. By connecting to the second voltage sampling point P2, the battery management system can acquire the voltage signal of the second sampling circuit and perform corresponding data processing. In such a design, the two series voltage-dividing resistors constitute a sampling module, but by adjusting the resistance values of the series resistors, the requirements in different situations can be met, and an appropriate voltage signal can be provided to the battery management system.

[0074] According to some embodiments of the present application, referring to FIG. 4, this withstand voltage module includes a controllable switch S GNDIt may include. It can be switched between two states of disconnection and connection to suit the requirements in two situations of withstand voltage test and insulation detection. Here, in the disconnected state, the withstand voltage module can play a role in improving the withstand voltage ability of the insulation sampling circuit. In the connected state, it can support the insulation detection by the battery management system.

[0075] With such a design, the ground wire can be disconnected when needed, providing a high withstand voltage ability to meet the requirements of the withstand voltage test. After the withstand voltage test is completed, the ground wire can be reconnected to meet the requirements of the insulation test.

[0076] It should be noted that in this embodiment, the term "switch" is used to represent a device that can be switched between two states of conduction and disconnection. Specifically, this can be achieved by selecting and using appropriate electronic components according to the requirements of the actual situation, such as MOS transistors, relays, or other types of electronic switches.

[0077] According to some embodiments of the present application, the withstand voltage test method can generally be performed once before the product is officially used, thereby ensuring that the product meets the withstand voltage standard. The embodiments of the present application provide a withstand voltage test method. Referring to FIG. 3, when performing the withstand voltage test, a preset voltage is applied between the positive bus P+ connected to the insulation sampling circuit and the ground GND, and between the negative bus P- connected to the insulation sampling circuit and the ground GND, respectively. At this time, by keeping the ground wire disconnected by the withstand voltage module, the insulation sampling circuit can have a withstand voltage ability that meets the usage requirements.

[0078] Here, this preset voltage is a voltage value determined according to the actually performed withstand voltage test, and specifically can be determined according to the requirements of the actual situation.

[0079] One merit of the withstand voltage test method according to the embodiment of the present application is that a withstand voltage module for cutting off the ground wire is designed to improve the withstand voltage capacity of the insulation sampling circuit, perform a withstand voltage test at an ultra-high voltage, and meet the requirements of the actual usage situation.

[0080] According to some embodiments of the present application, FIG. 5 is a control method for an insulation sampling circuit according to some embodiments of the present application. This control method may be executed by a battery management system, and is used to detect whether the withstand voltage module is normally connected, and perform insulation detection accordingly. Referring to FIG. 5, this may include the following steps.

[0081] S501: Control the withstand voltage module to be connected to the ground wire, control the first switch module to connect the first sampling module between the positive electrode bus and the ground wire, and control the second switch module to connect the second sampling module between the negative electrode bus and the ground wire.

[0082] Here, referring to FIG. 4, the battery management system provides corresponding control signals and simultaneously controls the first switch S1, the second switch S2, and the controllable switch S GND to be turned on, so that the first and second sampling modules are connected, and the state where the withstand voltage module is connected to the ground wire can be achieved. The specific control signals used can be determined according to the actual situation (for example, the switch elements specifically used in the switch module).

[0083] S502: Obtain the second sampling voltage formed by the second sampling module.

[0084] Here, the second sampling module connected to the detection circuit forms a corresponding voltage signal. In this embodiment, the voltage signal generated after the second sampling module is connected to the negative electrode bus and the ground wire is represented as the "second sampling voltage".

[0085] S503: Determine whether the ground wire is conducting according to the change trend of the second sampling voltage. If it is conducting, execute step S504; if it is not conducting, execute step S505.

[0086] Here, the "change trend" refers to the fluctuation situation of the voltage value of the second sampling voltage within a certain time period. Specifically, it can be characterized by various methods, such as the rising or falling speed, the time to rise or fall to the stable value, etc.

[0087] During the actual use process, the withstand voltage module may not be able to be connected to the ground wire due to various reasons, so the ground wire may still be in a disconnected state. Therefore, it is necessary to utilize the change trend of the sampling voltage to assist in detecting and judging whether the withstand voltage module is invalid or faulty.

[0088] S504: Perform insulation detection.

[0089] Here, the conduction of the ground wire indicates that the withstand voltage module is not faulty and the insulation sampling circuit is normal at this time. Thus, the battery management system can continue to perform subsequent insulation detection and calculate the insulation resistance.

[0090] S505: Output fault information.

[0091] Here, the disconnection of the ground wire indicates that the withstand voltage module is faulty and subsequent insulation detection cannot be performed at this time. Therefore, by outputting the fault information, it is presented to the maintainer or operator to promptly eliminate the fault. This fault information can specifically be realized in any appropriate type of format.

[0092] One merit of the control method according to the embodiment of the present application is that it realizes the detection of whether the ground wire is conducting according to the change trend of the second sampling voltage, and can timely discover the situation where the withstand voltage module becomes invalid or fails. Thereby, the reliability of insulation detection is effectively improved.

[0093] According to some embodiments of the present application, optionally, referring to FIG. 6, when the battery management system determines whether the ground wire is conducting according to the change trend, specifically, it includes the following steps.

[0094] S5031: Obtain the elapsed time from when the withstand voltage module is connected to the ground wire until the second sampling voltage becomes stable.

[0095] Here, after the withstand voltage module is connected to the ground wire, there is a charging process for the capacitor between the positive electrode busbar and the ground / negative electrode busbar and the ground. Thereby, the second sampling voltage takes a certain time to become stable.

[0096] Taking the insulation sampling circuit shown in FIG. 4 as an example, when the first switch S1, the second switch S2, and the controllable switch S GND are normally turned on, there is a charging process for the capacitor C between the positive electrode busbar and the ground / negative electrode busbar and the ground. Thereby, the second sampling voltage formed at the second voltage sampling point changes correspondingly from the moment when the first switch S1, the second switch S2, and the controllable switch S GND are connected, and becomes stable when the capacitor charging process ends. In FIG. 4, the capacitor between the positive electrode busbar / negative electrode busbar and the ground is represented by an equivalent capacitor C.

[0097] S5032: Determine whether the elapsed time meets a preset time threshold. If so, execute step S5033; if not, execute step S5034.

[0098] Here, the preset time threshold is a preset numerical value, specifically, it can be determined according to the actual circuit situation, and is used to assist in determining whether there is a charging process for the above-mentioned bus capacitor.

[0099] S5033: Determine that the ground wire is conductive.

[0100] Here, when the time required for the second sampling voltage to become stable is long, it can be considered that there is a charging process for capacitor C. Therefore, the withstand voltage module can be normally connected to the ground wire, and it can be determined that the ground wire is in a conductive state.

[0101] S5034: Determine that the ground wire is not conductive.

[0102] Conversely, when the time required for the second sampling voltage to become stable is short, it is shown that there is no charging process for the capacitor (not consistent with the normal situation). Therefore, it is shown that the withstand voltage module is not normally connected to the ground wire, and it can be determined that the ground wire is in a non-conductive state.

[0103] One merit of the method for judging whether the ground wire is conductive according to the embodiment of the present application is that it innovatively utilizes the charging process of the capacitor between the positive bus / negative bus and the ground to realize the detection of the withstand voltage module provided on the ground wire, and ensures that the ground wire is in a normal conductive state during insulation detection.

[0104] According to some embodiments of the present application, FIG. 7 is a schematic diagram of a control method according to some embodiments of the present application. Before the withstand voltage module is connected to the ground wire, the battery management system can execute the method steps shown in FIG. 7 to detect whether there is a fault or invalid situation in the sampling circuit itself. Referring to FIG. 7, this control method may include the following steps.

[0105] S701: Connect the first sampling module and the first resistor between the positive bus and the ground wire, and also connect the second sampling module and the second resistor between the negative bus and the ground wire.

[0106] Here, before the voltage withstand module is connected to the ground wire, the battery management system controls the switch module to turn on by sending a corresponding control signal, so as to connect both the resistor and the sampling module connected in parallel in the sampling circuit to the detection circuit (between the positive bus / negative bus and the ground wire), and it is possible to detect whether there is a fault in the sampling circuit.

[0107] S702: Obtain the voltage signal formed by the first sampling module or the second sampling module.

[0108] Here, this voltage signal may be the voltage signal formed by the first sampling module or the voltage signal formed by the second sampling module.

[0109] S703: Based on the voltage signal, determine whether there is a fault in the first sampling circuit and / or the second sampling circuit. If so, execute step S704; if not, execute step S705.

[0110] Here, when the specific circuit structure of the insulation sampling circuit is known, based on the voltage signal, the voltage between the positive bus and the negative bus at this time can be generally estimated. Thus, by judging whether there is a fault in the sampling circuit according to whether there is a large difference between the estimated theoretical result and the measured result, the reliability can be improved.

[0111] S704: Output fault information.

[0112] Here, when it is detected that there is a fault in the first sampling circuit and the second sampling circuit, it is necessary to output the corresponding fault information and present it to the user. Specifically, the battery management system can output this fault information in any appropriate format.

[0113] S705: Control so that the withstand voltage module is connected to the ground wire, control the first switch module so as to cut off the first resistor from between the positive electrode bus and the ground wire, and control the second switch module so as to cut off the second resistor from between the negative electrode bus and the ground wire.

[0114] Here, when it is detected that there is no fault, the battery management system can control the switch module to cut off the first resistor and the second resistor from the detection circuit, and prepare the operation steps for insulation detection.

[0115] One merit of the control method according to the embodiment of the present application is that it is possible to detect whether there is a fault in the first sampling circuit and the second sampling circuit before insulation detection, and ensure the reliability of the insulation detection result.

[0116] According to some embodiments of the present application, optionally, continuing to refer to FIG. 8, when the battery management system determines whether there is a fault in the sampling circuit according to the voltage signal, specifically, it includes the following steps.

[0117] S7031: Calculate the theoretical voltage difference between the positive electrode bus and the negative electrode bus based on the voltage signal.

[0118] Here, this theoretical voltage value refers to a theoretical value obtained by inverse calculation based on the sampling voltage acquired by the battery management system using the sampling module. The specific calculation process can be determined based on the specific circuit structure of the insulation sampling circuit.

[0119] S7032: Calculate the difference value between the theoretical voltage difference and the actual voltage difference between the positive electrode bus and the negative electrode bus.

[0120] Here, this actual voltage value refers to a known voltage applied between the positive electrode bus and the negative electrode bus. For example, it is the voltage of a battery pack connected to this positive electrode bus and negative electrode bus.

[0121] Referring to FIG. 3, when both the first sampling circuit and the second sampling circuit are normal, the estimated theoretical voltage value should generally correspond to the actual voltage value, and it can be expected that the difference between the two is not large. Thus, it is possible to determine whether the sampling circuit is normal based on the difference between the two.

[0122] S7033: Determine whether the ratio of the absolute value of the difference between the theoretical voltage difference and the actual voltage difference to the actual voltage difference is smaller than a preset difference threshold. If so, execute step S7034; if not, execute step S7035.

[0123] Here, specifically, this difference threshold can be determined according to the requirements of the actual situation and is related to parameters such as the resistance value of the actually used resistor and the battery voltage. This determination method characterizes the difference between the theoretical voltage difference and the actual voltage difference by using the magnitude of the proportion of the difference between the two in the actual voltage value as the judgment criterion.

[0124] In some embodiments, other appropriate statistical methods may be used to embody the difference between the two.

[0125] S7033: It is determined that there is no fault in the first sampling circuit and the second sampling circuit.

[0126] Here, when the division result of the absolute value of the difference value and the voltage signal is smaller than this preset threshold, at this time, the situations of both the first sampling circuit and the second sampling circuit are consistent with the expected situations, indicating that there is no fault.

[0127] S7034: It is determined that there is a fault in the first sampling circuit and the second sampling circuit.

[0128] Here, when the division result exceeds a preset threshold value, it indicates that either one of the first sampling circuit or the second sampling circuit does not match the expected situation. This explains that there is a fault in at least some of the electronic components in the first sampling circuit and the second sampling circuit, and it is necessary to report the fault information.

[0129] In such a design, according to the sampled voltage signal, calculate the theoretical voltage difference between the positive electrode bus and the negative electrode bus, and determine whether the first sampling circuit and the second sampling circuit match the expected normal situation according to the comparison result between this theoretical voltage difference and the actual voltage difference provided by the battery pack, so as to realize the fault detection of the first sampling circuit and the second sampling circuit.

[0130] According to some embodiments of the present application, referring to FIG. 9, FIG. 9 is an insulation detection method according to some embodiments of the present application. This insulation detection method may be executed by a battery management system and is used to detect the insulation resistance between the positive electrode bus and the ground wire / between the negative electrode bus and the ground wire. It may include the following steps.

[0131] S901: Control to connect the first sampling module and the second sampling module, and control the withstand voltage module to be connected to the ground wire.

[0132] Here, the battery management system can control to connect the first sampling module and the second sampling module and control the withstand voltage module to be connected to the ground wire by providing a corresponding control signal to the switch module.

[0133] S902: Obtain the first sampling voltage formed by the first sampling module and the second sampling voltage formed by the second sampling module respectively.

[0134] Here, as the first sampling module and the second sampling module are connected, referring to FIG. 3, they form voltage signals at corresponding voltage sampling nodes and provide them to the battery management system.

[0135] S903: Determine whether the first sampling voltage is greater than or equal to the second sampling voltage. If so, execute step S904; if not, execute step S905.

[0136] Here, when the first sampling voltage is large, it indicates that the equivalent insulation resistance on the corresponding side is larger. Thus, by executing step S904 and connecting the first resistor R1 to calculate the insulation resistance, the accuracy of the calculation can be improved. Conversely, when the second sampling voltage is large, it is necessary to connect the second resistor R2 for calculation.

[0137] S904: Control to connect the first resistor between the positive electrode bus and the ground wire.

[0138] Here, referring to FIG. 3, the battery management system can connect the first resistor between the positive electrode bus and the ground wire by controlling the first switch S1 to be turned on. At this time, the connected first resistor is connected in parallel with the first sampling module.

[0139] S906: After the first resistor is connected, obtain the third sampling voltage formed by the first sampling module and the fourth sampling voltage formed by the second sampling module.

[0140] Here, after the first resistor is connected, a resistor connected in parallel to the first sampling circuit is increased, so that the voltage values ​​of the first sampling module and the second sampling module change correspondingly. In this embodiment, the voltage values ​​detected and acquired by the first sampling module and the second sampling module after the first resistor is connected are called the third sampling voltage and the fourth sampling voltage, respectively, to distinguish them from the first sampling voltage and the second sampling voltage detected and acquired by the first sampling module and the second sampling module before the first resistor is connected.

[0141] S908: Calculate a first insulation resistance between the positive busbar and the ground line and a second insulation resistance between the negative busbar and the ground line based on the first sampled voltage, the second sampled voltage, the third sampled voltage, and the fourth sampled voltage.

[0142] 3, what needs to be calculated in insulation detection are two unknown quantities: the first insulation resistance RP between the positive busbar and the ground wire, and the second insulation resistance Rn between the negative busbar and the ground wire. If the specific configurations of the first sampling circuit and the second sampling circuit are known, the two unknown quantities of the first insulation resistance and the second insulation resistance can be solved by solving two simultaneous equations, one before the first resistance is connected and one after the first resistance is connected.

[0143] S905: Controlling to connect a second resistor between the negative bus bar and the ground bar.

[0144] 3, the battery management system can control the second switch S2 to be turned on to connect the second resistor R2 between the positive bus and the ground line, and the connected second resistor is connected in parallel to the second sampling module.

[0145] S907: After the second resistor is connected, obtain a fifth sampling voltage formed by the first sampling module and a sixth sampling voltage formed by the second sampling module.

[0146] Here, after the second resistor is connected, a resistor connected in parallel to the second sampling circuit is increased, so that the voltage values ​​of the first sampling module and the second sampling module change correspondingly. In this embodiment, the voltage values ​​detected by the first sampling module and the second sampling module after the second resistor is connected are called the fifth sampling voltage and the sixth sampling voltage, respectively, to distinguish them from the first sampling voltage and the second sampling voltage detected by the first sampling module and the second sampling module before the second resistor is connected.

[0147] S909: Calculate a first insulation resistance between the positive busbar and the ground line and a second insulation resistance between the negative busbar and the ground line based on the first sampled voltage, the second sampled voltage, the fifth sampled voltage and the sixth sampled voltage.

[0148] Here, similarly to step S908 above, when the specific configurations of the first sampling circuit and the second sampling circuit are known, the two unknown quantities of the first insulation resistance Rp and the second insulation resistance Rn can be solved by setting up two simultaneous equations, one before the second resistor is connected and one after the second resistor is connected.

[0149] One advantage of the insulation detection method of the embodiment of the present application is that a more accurate insulation resistance can be calculated and obtained by determining whether to connect the first resistor or the second resistor according to the magnitude relationship between the first sampled voltage and the second sampled voltage.

[0150] According to some embodiments of the present application, FIGS. 10a to 10e are schematic diagrams of an insulation sampling circuit according to an embodiment of the present application during use. Referring to FIGS. 10a to 10e, this insulation sampling circuit includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a first switch S1, a second switch S2, a third switch S3, a fourth switch S4, and a controllable switch S GND The first resistor R1 and the second resistor R2 have the same resistance value, and the fifth resistor R5 and the fourth resistor R4 have the same resistance value.

[0151] Here, the first resistor R1, the third resistor R3, the fifth resistor R5, the first switch S1, and the third switch S3 constitute the first sampling circuit 100. One end of the first resistor R1 is connected to the positive bus P+, and the other end of the first resistor R1 is connected to the ground GND by the first switch S1. One end of the third resistor R3 is connected to the positive bus P+, and the other end of the third resistor R3 is connected to one end of the fifth resistor R5. The other end of the fifth resistor R5 is connected to the ground GND by the third switch S3. The connection node between the series-connected third resistor R3 and fifth resistor R5 forms the first voltage sampling point P1.

[0152] In some embodiments, the first voltage sampling point P1 may be connected to an analog-to-digital conversion chip ADC. After converting the analog voltage signal into a digital signal, the analog-to-digital conversion chip ADC can provide the voltage value in digital signal form to the microcontroller MCU by the communication shielding chip.

[0153] The second resistor R2, the fourth resistor R4, the sixth resistor R6, the second switch S2, and the fourth switch S4 constitute a second sampling circuit. One end of the second resistor R2 is connected to the negative busbar P-, and the other end of the second resistor R2 is connected to the ground GND by the second switch S2. One end of the fourth resistor R4 is connected to the negative busbar P-, and the other end of the fourth resistor R4 is connected to one end of the sixth resistor R6. The other end of the sixth resistor R6 is connected to the ground GND by the fourth switch S4. The connection node between the serially connected fourth resistor R4 and sixth resistor R6 forms a second voltage sampling point P2.

[0154] In some embodiments, the second voltage sampling point P2 may be connected to an analog-to-digital conversion chip ADC. After converting the analog voltage signal into a digital signal, the analog-to-digital conversion chip ADC can provide the voltage value in digital signal form to the microcontroller MCU by the communication shielding chip.

[0155] The controllable switch S GND is installed on the ground GND, located between the first / second sampling circuits and the ground node 3, and is used to control the disconnection or conduction of the ground wire.

[0156] Referring to FIG. 10a, in the initial state, the controllable switch S GND keeps the ground wire disconnected. The insulation sampling circuit has a high withstand voltage capacity. Thereby, during the withstand voltage test, the voltage Vh applied between the high voltage positive electrode 1 and the ground node 3, and the voltage Vh applied between the high voltage negative electrode 2 and the ground node 3 are satisfied.

[0157] Referring to FIG. 10b, when the battery management system detects the low voltage power-on (e.g., 12V) of the vehicle and prepares for insulation detection, the first switch S1, the second switch S2, the third switch S3, and the fourth switch S4 are turned on, and the controllable switch S GNDBy controlling to turn off, the failure detection of the first sampling circuit and the second sampling circuit is executed.

[0158] When executing the failure detection step, the battery management system can calculate the theoretical voltage value U3 between the high-voltage positive electrode 1 and the high-voltage negative electrode 2 according to the following formula (1) based on the second sampling voltage collected by the second sampling circuit.

[0159]

Equation

[0160] Here, U adc is the voltage value sampled by the analog-to-digital conversion chip ADC at the second voltage sampling point, r1 is the resistance value of the first resistor R1 (which is the same as the resistance value of the second resistor R2), r3 is the resistance value of the third resistor R3, r4 is the resistance value of the fourth resistor R4 (which is the same as the resistance value of the fifth resistor R5), and r6 is the resistance value of the sixth resistor R6.

[0161] Then, the difference X between the theoretical voltage value U3 and the actual voltage value U4 between the high-voltage positive electrode 1 and the high-voltage negative electrode 2 is calculated according to the following formula (2).

[0162]

Equation

[0163] When the difference X between the two is smaller than the preset threshold value, the battery management system can determine that the first sampling circuit and the second sampling circuit are in a normal state and there is no failure. When the difference X between the two is greater than or equal to the preset threshold value, the battery management system can determine that there is a failure in the first sampling circuit and the second sampling circuit, and it is necessary to output the failure information and prompt the user to process it in a timely manner.

[0164] Referring to FIG. 10c, when the battery management system detects and determines that there is no failure in the first sampling circuit and the second sampling circuit, it can control the third switch S3, the fourth switch S4, and the controllable switch S GND to be turned on.

[0165] When the battery management system determines that the second sampling voltage provided by the second sampling circuit is the time to control the third switch S3, the fourth switch S4, and the controllable switch S GND to be turned on, it can detect whether the controllable switch S GND is successfully turned on according to whether the rising and falling trends of the voltage coincide with the charging process of the capacitor C between the positive bus / negative bus and the ground until it stabilizes.

[0166] If it is determined that the controllable switch S GND is not successfully turned on, the corresponding fault information can be output and presented to the user to prompt for urgent processing. If it is determined that the controllable switch S GND is successfully turned on, the subsequent insulation detection steps can be continuously executed.

[0167] In the switch state of FIG. 10c, the battery management system respectively obtains the first sampling voltage V1 at the first voltage sampling point P1 and the second sampling voltage V2 at the second voltage sampling point P2.

[0168] Referring to FIG. 10d, when the first sampling voltage V1 is greater than or equal to the second sampling voltage V2, the battery management system can connect the first resistor R1 by controlling the first switch S1 to be turned on. Then, the third sampling voltage V3 at the first voltage sampling point P1 and the fourth sampling voltage V4 at the second voltage sampling point P2 at this time are respectively obtained.

[0169] Finally, the first insulation resistance Rp between the high-voltage positive electrode 1 and the ground node 3 and the second insulation resistance Rn between the high-voltage negative electrode 2 and the ground node 3 can be calculated by the following formulas (3-1) and (3-2), respectively.

[0170]

Number

[0171]

Number

[0172] Here, r1 is the resistance value of the first resistor R1 (which is the same as the resistance value of the second resistor R2), r3 is the resistance value of the third resistor R3, r4 is the resistance value of the fourth resistor R4 (which is the same as the resistance value of the fifth resistor R5), and r6 is the resistance value of the sixth resistor R6.

[0173] Referring to FIG. 10e, when the first sampling voltage V1 is smaller than the second sampling voltage V2, the battery management system can control the second switch S2 to be turned on to connect the second resistor R2. Thereafter, the fifth sampling voltage V5 at the first voltage sampling point P1 and the sixth sampling voltage V6 at the second voltage sampling point P2 at this time are obtained, respectively.

[0174] Finally, the first insulation resistance Rp between the high-voltage positive electrode 1 and the ground node 3 and the second insulation resistance Rn between the high-voltage negative electrode 2 and the ground node 3 can be calculated by the following formulas (4-1) and (4-2), respectively.

[0175]

Number

[0176]

Number

[0177] Here, r1 is the resistance value of the first resistor R1 (which is the same as the resistance value of the second resistor R2), r3 is the resistance value of the third resistor R3, r4 is the resistance value of the fourth resistor R4 (which is the same as the resistance value of the fifth resistor R5), and r6 is the resistance value of the sixth resistor R6.

[0178] According to some embodiments of the present application, referring to FIG. 11, FIG. 11 is a control device for an insulation sampling circuit according to an embodiment of the present application. This control device may be implemented by a battery management system. This may include a switch control unit 1110, a ground wire detection unit 1120, an insulation detection unit 1130, and a fault reporting unit 1140.

[0179] Here, the switch control unit 1110 is used to control the voltage withstand module to be connected to the ground wire, control the first switch module to connect the first sampling module between the positive bus and the ground wire, and control the second switch module to connect the second sampling module between the negative bus and the ground wire. The ground wire detection unit 1120 is used to obtain the second sampling voltage formed by the second sampling module and determine whether the ground wire is conductive according to the change trend of the second sampling voltage. The insulation detection unit 1130 is used to perform insulation detection when the ground wire is conductive. The fault reporting unit 1140 is used to output fault information when the ground wire is disconnected.

[0180] One advantage of the control method according to the embodiment of the present application is that it can realize the detection of whether the ground wire is conductive according to the change trend of the second sampling voltage, and can timely discover the situation where the voltage withstand module is invalid or faulty, thereby effectively improving the reliability of insulation detection.

[0181] According to some embodiments of the present application, optionally, the insulation detection unit 1130 specifically obtains the elapsed time from when the withstand voltage module is connected to the ground wire until the second sampling voltage becomes stable, determines whether the elapsed time meets a preset time threshold, and if it meets, is used to determine that the ground wire is conducting. Such a design innovatively utilizes the charging process of the capacitor between the positive busbar / negative busbar and the ground to realize the detection of the withstand voltage module, and can ensure that the ground wire is in a normal conducting state during insulation detection.

[0182] According to some embodiments of the present application, referring to FIG. 12, FIG. 12 is a control device for an insulation sampling circuit according to some other embodiments of the present application. In addition to the functional modules shown in FIG. 11, this control device further includes a detection trigger unit 1150, a signal collection unit 1160, and a fault detection unit 1170.

[0183] Here, the detection trigger unit 1150 is used to connect the first sampling module and the first resistor of the insulation sampling circuit between the positive busbar and the ground wire, and also connect the second sampling module and the second resistor between the negative busbar and the ground wire by controlling the switch module. The signal collection unit 1160 is used to obtain the voltage signal formed by the first sampling module or the second sampling module.

[0184] The fault detection unit 1170 is used to determine whether there is a fault in the first sampling circuit and the second sampling circuit based on the voltage signal. The fault reporting unit 1140 is further used to output fault information if there is a fault. The insulation detection unit 1130 is further used to control the withstand voltage module to be connected to the ground wire when there is no fault, control the first switch module to disconnect the first resistor between the positive busbar and the ground wire, and control the second switch module to disconnect the second resistor between the negative busbar and the ground wire to prepare for insulation detection.

[0185] Such a design ensures the reliability of the insulation detection result by adding a step of detecting whether there is a fault in the first sampling circuit and the second sampling circuit before the insulation detection.

[0186] According to some embodiments of the present application, optionally, the fault detection unit 1170 is specifically configured to calculate the theoretical voltage difference between the positive electrode bus and the negative electrode bus based on the voltage signal, calculate the difference value between the theoretical voltage difference and the actual voltage difference between the positive electrode bus and the negative electrode bus, and determine whether the ratio of the absolute value of the difference value between the theoretical voltage difference and the actual voltage difference to the actual voltage difference is smaller than a preset difference threshold. If so, it is determined that there is no fault in the first sampling circuit and the second sampling circuit. Otherwise, it is used to determine that there is a fault in the first sampling circuit and the second sampling circuit.

[0187] In such a design, the theoretical voltage difference between the positive electrode bus and the negative electrode bus is calculated according to the sampled voltage signal, and whether the first sampling circuit and the second sampling circuit match the expected normal situation is determined according to the comparison result between the theoretical voltage difference and the actual voltage difference provided by the battery pack, so as to realize the fault detection of the first sampling circuit and the second sampling circuit.

[0188] According to some embodiments of the present application, optionally, the insulation detection unit 1130 is specifically configured to respectively obtain the first sampling voltage formed by the first sampling module and the second sampling voltage formed by the second sampling module, and is used to execute the corresponding insulation detection step according to the comparison result of the magnitudes of the first sampling voltage and the second sampling voltage.

[0189] On the one hand, when the first sampling voltage is greater than or equal to the second sampling voltage, the insulation detection unit 1130 controls to connect the first resistor between the positive busbar and the ground wire. After the first resistor is connected, the third sampling voltage formed by the first sampling module and the fourth sampling voltage formed by the second sampling module are acquired, and based on the first sampling voltage, the second sampling voltage, the third sampling voltage, and the fourth sampling voltage, they may be used to calculate the first insulation resistance between the positive busbar and the ground wire and the second insulation resistance between the negative busbar and the ground wire.

[0190] On the other hand, when the first sampling voltage is less than the second sampling voltage, the insulation detection unit 1130 controls to connect the second resistor between the negative busbar and the ground wire. After the second resistor is connected, the fifth sampling voltage formed by the first sampling module and the sixth sampling voltage formed by the second sampling module are acquired, and based on the first sampling voltage, the second sampling voltage, the fifth sampling voltage, and the sixth sampling voltage, they may be used to calculate the first insulation resistance between the positive busbar and the ground wire and the second insulation resistance between the negative busbar and the ground wire.

[0191] Such a design can determine whether to connect the first resistor or the second resistor according to the magnitude relationship between the first sampling voltage and the second sampling voltage, thereby making the calculated and acquired insulation resistance result more accurate.

[0192] It should be noted that in the embodiments of the present application, the functional units of the control device of the insulation sampling circuit are classified according to the method steps to be executed. In some embodiments, according to the requirements of the actual situation, one or more functional units (switch control unit, ground wire detection unit, insulation detection unit, fault reporting unit, detection trigger unit, signal collection unit, and fault detection unit) in the control device of the embodiments of the present application are divided into more functional units, so as to execute the corresponding method steps. In some other embodiments, by integrating one or more functional units in the control device of the embodiments of the present application into fewer functional units, the corresponding method steps can also be executed.

[0193] According to some embodiments of the present application, referring to FIG. 13, FIG. 13 is a schematic structural diagram of a battery management system according to an embodiment of the present application. This battery management system may be used in any type of battery or power consumption device. Here, its specific implementation is not limited.

[0194] As shown in FIG. 13, this battery management system may include a processor 1310, a communication interface 1320, a memory 1330, and a communication bus 1340.

[0195] Here, the processor 1310, the communication interface 1320, and the memory 1330 complete their mutual communication via the communication bus 1340. The communication interface 1320 is used to be communicably connected to other devices (for example, connected to an insulation sampling circuit to obtain the voltage signals of the first sampling module and the second sampling module). The processor 1310 is used to call the program 1350 to execute one or more method steps in the control method of the insulation sampling circuit in the above embodiments. Specifically, the program 1350 may include program code or computer operation instructions.

[0196] In this embodiment, according to the type of hardware used, the processor 1310 may be a central processing unit, other general-purpose processors, digital signal processors, application-specific integrated circuits, field programmable gate arrays or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware assemblies, etc.

[0197] The memory 1330 is used to store the program 1350. The memory 1330 may include high-speed RAM memory and may also include non-volatile memory, such as at least one magnetic disk memory.

[0198] Embodiments of the present application further provide a computer-readable storage medium. This computer-readable storage medium may be a non-volatile computer-readable storage medium. A computer program is stored in this computer-readable storage medium.

[0199] Here, when the computer program is executed by the processor, one or more method steps in the control method of the insulation sampling circuit in the above embodiment are realized. The complete computer program product is embodied in one or more computer-readable storage media having the computer program disclosed in the embodiments of the present application (including, but not limited to, magnetic disk memory, CD-ROM, optical memory, etc.).

[0200] Finally, it should be noted that each of the above embodiments is only used to explain the technical solution of this application and does not limit it. Although this application has been described in detail with reference to each of the foregoing embodiments, as can be understood by those skilled in the art, it is still possible to modify the technical solutions described in each of the foregoing embodiments, or equivalently replace some or all of their technical features. These modifications or replacements do not deviate from the essence of the corresponding technical solutions from the scope of the technical solutions of each embodiment of this application and should be included within the scope of the claims and the specification of this application. In particular, as long as there is no structural contradiction, any of the technical features mentioned in each embodiment can be combined in any way. This application is not limited to the specific embodiments disclosed in this specification and includes all technical solutions included in the scope of the claims.

Claims

1. A withstand voltage test method used for an insulation sampling circuit, comprising: The insulation sampling circuit includes: A first sampling circuit including a first sampling module, a first resistor, and a first switch module, wherein the first resistor is connected in parallel to the first sampling module, and the first switch module is used to control the connection of the first sampling module and / or the first resistor between the positive bus and the ground wire; A second sampling circuit including a second sampling module, a second resistor, and a second switch module, wherein the second resistor is connected in parallel to the second sampling module, and the second switch module is used to control the connection of the second sampling module and / or the second resistor between the negative bus and the ground wire; A withstand voltage module installed on the ground wire, which is capable of switching control between a state where the ground wire is disconnected from the ground and a state where the ground wire is electrically connected to the ground; Including: The first sampling module divides the voltage across both ends to provide a first voltage sampling point, and the first sampling circuit detects the voltage at the first voltage sampling point; The second sampling module divides the voltage across both ends to provide a second voltage sampling point, and the second sampling circuit detects the voltage at the second voltage sampling point; The withstand voltage test method includes: Applying a preset voltage between the positive bus and the ground wire connected to the insulation sampling circuit, and applying a preset voltage between the negative bus and the ground wire connected to the insulation sampling circuit; A withstand voltage test method, wherein the withstand voltage module of the insulation sampling circuit keeps the ground wire disconnected from the ground.

2. A control method for an insulation sampling circuit, comprising: The insulation sampling circuit includes: A first sampling circuit including a first sampling module, a first resistor, and a first switch module, wherein the first resistor is connected in parallel to the first sampling module, and the first switch module is used to control the connection of the first sampling module and / or the first resistor between the positive bus and the ground wire. A second sampling circuit including a second sampling module, a second resistor, and a second switch module, wherein the second resistor is connected in parallel to the second sampling module, and the second switch module is used to control the connection of the second sampling module and / or the second resistor between the negative bus and the ground wire. A withstand voltage module installed on the ground wire, which can be switched and controlled between a state where the ground wire is disconnected from the ground and a state where the ground wire is conductive to the ground. including The first sampling module divides the voltage at both ends to provide a first voltage sampling point, and the first sampling circuit detects the voltage at the first voltage sampling point. The second sampling module divides the voltage at both ends to provide a second voltage sampling point, and the second sampling circuit detects the voltage at the second voltage sampling point. The control method is as follows: A first control that controls the withstand voltage module of the insulation sampling circuit to conduct the ground wire to the ground, controls the first switch module of the insulation sampling circuit to connect the first sampling module between the positive bus and the ground wire, and controls the second switch module to connect the second sampling module between the negative bus and the ground wire. Obtaining a second sampling voltage formed by the second sampling module in a state where the first control is performed. Judging whether the ground wire is conductive according to the change trend of the second sampling voltage. Performing insulation detection when the ground wire is conductive. Outputting fault information when the ground wire is disconnected from the ground. A control method including the above steps.

3. The first switch module includes a first switch and a third switch, and the second switch module includes a second switch and a fourth switch. One end of the first resistor is connected to the positive busbar, and the other end of the first resistor is connected to the ground wire by the first switch. One end of the first sampling module is connected to the positive busbar, and the other end of the first sampling module is connected to the ground wire by the third switch. One end of the second resistor is connected to the negative busbar, and the other end of the second resistor is connected to the ground wire by the second switch. One end of the second sampling module is connected to the negative busbar, and the other end of the second sampling module is connected to the ground wire by the fourth switch. The control method according to claim 2.

4. The first sampling module includes a third resistor and a fifth resistor, and the second sampling module includes a fourth resistor and a sixth resistor. One end of the third resistor is connected to the positive busbar, the other end of the third resistor is connected to one end of the fifth resistor, the other end of the fifth resistor is connected to the ground wire by the third switch, and the connection node between the third resistor and the fifth resistor forms the first voltage sampling point. One end of the fourth resistor is connected to the negative busbar, the other end of the fourth resistor is connected to one end of the sixth resistor, the other end of the sixth resistor is connected to the ground wire by the fourth switch, and the connection node between the fourth resistor and the sixth resistor forms the second voltage sampling point. The control method according to claim 3.

5. The withstand voltage module includes a controllable switch installed on the ground wire. The control method according to claim 2.

6. Judging whether the ground wire is conducting according to the change trend of the second sampling voltage includes: Obtaining the elapsed time from when the withstand voltage module conducts the ground wire to the ground until the second sampling voltage becomes stable; Judging whether the elapsed time meets a preset time threshold; If it meets, determining that the ground wire is conducting; The control method according to claim 2.

7. Before controlling the withstand voltage module to conduct the ground wire to the ground, the method includes: connecting the first sampling module and the first resistor of the insulation sampling circuit between the positive bus and the ground wire, and connecting the second sampling module and the second resistor between the negative bus and the ground wire; acquiring a voltage signal formed by the first sampling module or the second sampling module; judging whether there is a fault in the first sampling circuit and the second sampling circuit based on the voltage signal; outputting fault information if there is a fault; if there is no fault, controlling the withstand voltage module to conduct the ground wire to the ground, controlling the first switch module to disconnect the first resistor from between the positive bus and the ground wire, and controlling the second switch module to disconnect the second resistor from between the negative bus and the ground wire; The control method according to claim 2, further comprising the above steps.

8. Judging whether there is a fault in the first sampling circuit and the second sampling circuit based on the voltage signal includes: calculating a theoretical voltage difference between the positive bus and the negative bus based on the voltage signal; calculating a difference value between the theoretical voltage difference and the actual voltage difference between the positive bus and the negative bus; judging whether an absolute value of the difference value between the theoretical voltage difference and the actual voltage difference is smaller than a preset difference threshold value compared with the actual voltage difference; if the ratio is smaller than the difference threshold value, determining that there is no fault in the first sampling circuit and the second sampling circuit; if the ratio is not smaller than the difference threshold value, determining that there is a fault in the first sampling circuit and the second sampling circuit. The control method according to claim 7, including the above steps.

9. When the ground wire is conducting, performing insulation detection includes: respectively acquiring a first sampling voltage formed by the first sampling module and a second sampling voltage formed by the second sampling module; when the first sampling voltage is greater than or equal to the second sampling voltage, controlling to connect the first resistor between the positive bus and the ground wire; After the first resistor is connected, obtaining a third sampling voltage formed by the first sampling module and a fourth sampling voltage formed by the second sampling module; Calculating a first insulation resistance between the positive electrode bus and the ground wire and a second insulation resistance between the negative electrode bus and the ground wire based on the first sampling voltage, the second sampling voltage, the third sampling voltage, and the fourth sampling voltage; When the first sampling voltage is smaller than the second sampling voltage, controlling to connect the second resistor between the negative electrode bus and the ground wire; After the second resistor is connected, obtaining a fifth sampling voltage formed by the first sampling module and a sixth sampling voltage formed by the second sampling module; Calculating a first insulation resistance between the positive electrode bus and the ground wire and a second insulation resistance between the negative electrode bus and the ground wire based on the first sampling voltage, the second sampling voltage, the fifth sampling voltage, and the sixth sampling voltage; The control method according to any one of claims 2 to 8, including the above steps.

10. A control device for an insulation sampling circuit, wherein the insulation sampling circuit includes A first sampling circuit including a first sampling module, a first resistor, and a first switch module, wherein the first resistor is connected in parallel to the first sampling module, and the first switch module is used to control to connect the first sampling module and / or the first resistor between the positive electrode bus and the ground wire; A second sampling circuit including a second sampling module, a second resistor, and a second switch module, wherein the second resistor is connected in parallel to the second sampling module, and the second switch module is used to control to connect the second sampling module and / or the second resistor between the negative electrode bus and the ground wire; A withstand voltage module installed on the ground wire, which can be switched and controlled between a state where the ground wire is disconnected from the ground and a state where the ground wire is electrically connected to the ground; including the above components. The first sampling module divides the voltage at both ends to provide a first voltage sampling point, and the first sampling circuit detects the voltage at the first voltage sampling point. The second sampling module divides the voltage at both ends to provide a second voltage sampling point, and the second sampling circuit detects the voltage at the second voltage sampling point. The control device is a switch control unit for performing a first control to control the voltage withstand module of the insulation sampling circuit to conduct the ground wire to the ground, control the first switch module of the insulation sampling circuit to connect the first sampling module between the positive electrode bus and the ground wire, and control the second switch module to connect the second sampling module between the negative electrode bus and the ground wire; a ground wire detection unit for obtaining a second sampling voltage formed by the second sampling module in a state where the first control is performed and determining whether the ground wire is conductive according to the change trend of the second sampling voltage; an insulation detection unit for performing insulation detection when the ground wire is conductive; a fault reporting unit for outputting fault information when the ground wire is disconnected from the ground; The control device includes the above components.

11. A battery management system including a processor and a memory, wherein computer program instructions are stored in the memory, and when the computer program instructions are called by the processor, the processor is caused to execute the control method according to any one of claims 2 to 8.

12. A power consumption device including an insulation sampling circuit, a battery, a load, and the battery management system according to claim 11, wherein the battery is connected to the battery management system and supplies power to the load. The insulation sampling circuit is a first sampling circuit including a first sampling module, a first resistor, and a first switch module, wherein the first resistor is connected in parallel with the first sampling module, and the first switch module is used to control to connect the first sampling module and / or the first resistor between the positive electrode bus and the ground wire. A second sampling circuit including a second sampling module, a second resistor, and a second switch module, wherein the second resistor is connected in parallel to the second sampling module, and the second switch module is used to control the connection of the second sampling module and / or the second resistor between the negative bus and the ground wire. A withstand voltage module installed on the ground wire, which is capable of switching control between a state where the ground wire is disconnected from the ground and a state where the ground wire is conductive to the ground. Including The first sampling module divides the voltage at both ends to provide a first voltage sampling point, and the first sampling circuit detects the voltage at the first voltage sampling point. The second sampling module divides the voltage at both ends to provide a second voltage sampling point, and the second sampling circuit detects the voltage at the second voltage sampling point. A power consumption device.

13. A computer storage medium having computer program instructions stored thereon, wherein when the computer program instructions are called by a processor, the processor is caused to execute the control method according to any one of claims 2 to 8. A computer storage medium.

Images