Insulation sampling circuit, control method thereof, withstand voltage test method and electrical equipment

Abstract

The present application discloses an insulation sampling circuit, its control method, withstand voltage test method and electrical equipment. The insulation sampling circuit includes: a first sampling circuit composed of a first sampling module, a first resistor and a first switch module; a second sampling circuit composed of a second sampling module, a second resistor and a second switch module and a withstand voltage module. The first resistor is connected in parallel with the first sampling module; the first switch module is used to control the first sampling module and / or the first resistor to be connected between the positive bus and the ground; the second resistor is connected in parallel with the second sampling module; the second switch module is used to control the second sampling module and / or the second resistor to be connected between the negative bus and the ground; the withstand voltage module is set on the ground to disconnect the ground, which can effectively improve the withstand voltage capability between the positive bus and the ground / between the negative bus and the ground to meet the needs of higher voltage withstand voltage testing.

Description

Technical Field

[0001] The present application relates to the field of insulation detection, and specifically to an insulation sampling circuit, a control method thereof, a withstand voltage testing method and electrical equipment. Background Art

[0002] Insulation testing is used in a variety of scenarios, including electric vehicles, hybrid vehicles, and charging stations. It measures the insulation resistance between the positive and negative high-voltage terminals and ground to assess insulation performance. This method ensures electrical safety and prevents direct harm from high voltage. However, current insulation testing circuits cannot address the limited voltage withstand capability of sampling circuits. Summary of the Invention

[0003] In view of the above problems, the present application provides an insulation sampling circuit, a control method thereof, a withstand voltage test method and an electrical device, which can solve the problem of limited withstand voltage capability of the sampling circuit for insulation detection.

[0004] In a first aspect, the present application provides an insulation sampling circuit. The 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 first sampling module and / or the first resistor to be connected between the positive bus and the ground; 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 second sampling module and / or the second resistor to be connected between the negative bus and the ground. The withstand voltage module is set on the ground to disconnect the ground.

[0005] In the technical solution of the embodiments of this application, by adding a withstand voltage module to the ground wire that can keep the ground wire disconnected, the withstand voltage between the positive busbar and the ground wire, and between the negative busbar and the ground wire, can be effectively improved to meet the needs of higher voltage withstand voltage testing. Furthermore, the installation of the withstand voltage module on the ground wire also facilitates the detection of the actual operating status of the withstand voltage module, making it easier to take into account and meet different testing requirements.

[0006] In some embodiments, the first switch module includes: a first switch and a third switch; the second switch module includes: a second switch and a fourth switch. One end of the first resistor is connected to the positive bus, and the other end of the first resistor is connected to the ground through the first switch; one end of the first sampling module is connected to the positive bus, and the other end of the first sampling module is connected to the ground through the third switch; one end of the second resistor is connected to the positive bus, and the other end of the second resistor is connected to the ground through the second switch; one end of the second sampling module is connected to the positive bus, and the other end of the second sampling module is connected to the ground through the fourth switch. The switch module of the embodiment of the present application consists of two switches, which are used to independently control whether the sampling module and the known resistor are connected, so as to facilitate the implementation of different detection steps.

[0007] In some embodiments, the first sampling module includes: a third resistor and a fifth resistor; the second sampling module includes: a fourth resistor and a sixth resistor. One end of the third resistor is connected to the positive bus, 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 line through 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 positive bus, 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 line through the fourth switch, and the connection node between the fourth resistor and the sixth resistor forms a second voltage sampling point. The embodiment of the present application provides a sampling module composed of two series resistors, which can conveniently meet the needs of actual application situations by adjusting the resistance value of the resistor.

[0008] In some embodiments, the withstand voltage module includes a controllable switch disposed on the ground wire. This design can disconnect the ground wire when needed, providing a strong withstand voltage capability to meet the requirements of the withstand voltage test, and can also restore the ground wire to conduction after the withstand voltage test to meet the requirements of the insulation test.

[0009] In a second aspect, the present application provides a withstand voltage test method. This withstand voltage test method is applied to the insulation sampling circuit described above. The withstand voltage test method may include: applying a preset voltage between a positive busbar connected to the insulation sampling circuit and a ground line, and applying a preset voltage between a negative busbar connected to the insulation sampling circuit and a ground line; wherein the withstand voltage module of the insulation sampling circuit maintains the ground line disconnected.

[0010] In the technical solution of the embodiment of the present application, in addition to the switch module, a voltage-withstand module for disconnecting the ground wire is also provided between the positive busbar and the ground wire, or between the negative busbar and the ground wire. This gives the insulation sampling circuit a strong voltage-withstand capability, enabling it to complete high-voltage withstand voltage tests.

[0011] In a third aspect, the present application provides a control method for the insulation sampling circuit described above. The control method includes: controlling the withstand voltage module of the insulation sampling circuit to connect to the ground line, controlling the first switch module of the insulation sampling circuit to connect the first sampling module between the positive bus and the ground line, and controlling the second switch module to connect the second sampling module between the negative bus and the ground line; obtaining a second sampling voltage generated by the second sampling module; determining whether the ground line is conductive based on the change trend of the second sampling voltage; performing insulation detection when the ground line is conductive; and outputting fault information when the ground line is disconnected.

[0012] In the technical solution of the embodiment of the present application, whether the ground wire is turned on is detected by detecting the change trend of the sampled voltage, which can detect and distinguish the failure or failure of the withstand voltage module, thereby improving the reliability of the insulation detection result.

[0013] In some embodiments, judging whether the ground wire is conductive based on the changing trend of the second sampling voltage specifically includes: obtaining the time elapsed from the connection between the withstand voltage module and the ground wire to the time when the second sampling voltage reaches stability; judging whether the elapsed time meets a preset time threshold, and if so, determining that the ground wire is conductive. Such a design utilizes the charging process of a capacitor (for example, the capacitor can be a capacitor located on the body of a new energy vehicle equipped with a high-voltage battery system) when the ground wire is conductive to detect whether the withstand voltage module has been normally connected to the ground wire, thereby ensuring the accuracy of the insulation test results.

[0014] In some embodiments, before controlling the withstand voltage module to connect to the ground line, the method further includes: connecting the first sampling module and the first resistor of the insulation sampling circuit between the positive bus and the ground line, and connecting the second sampling module and the second resistor between the negative bus and the ground line; obtaining a voltage signal formed in the first sampling module or the second sampling module; judging whether the first sampling circuit and the second sampling circuit have a fault based on the voltage signal; outputting fault information when a fault exists; and controlling the withstand voltage module to connect to the ground line when no fault exists, controlling the first switch module to disconnect the first resistor from between the positive bus and the ground line, and controlling the second switch module to disconnect the second resistor from between the negative bus and the ground line. This design also provides an additional detection procedure before performing insulation testing to ensure that the sampling circuit is in a normal working state.

[0015] In some embodiments, determining whether the first sampling circuit and the second sampling circuit have faults based on the voltage signal specifically includes: calculating a theoretical voltage difference between the positive bus and the negative bus based on the voltage signal; calculating a difference between the theoretical voltage difference and an actual voltage difference between the positive bus and the negative bus; determining whether a ratio between an absolute value of the difference between the theoretical voltage difference and the actual voltage difference and the actual voltage difference is less than a preset difference threshold; if so, determining that the first sampling circuit and the second sampling circuit do not have faults; if not, determining that the first sampling circuit and the second sampling circuit have faults.

[0016] The technical solution of the present embodiment is designed to infer the theoretical voltage between the positive and negative busbars based on the sampled voltage signals. The difference between the theoretical voltage inferred from the sampling results and the actual voltage is then used to determine whether a fault exists in the first and second sampling circuits, thereby improving the reliability of insulation testing.

[0017] In some embodiments, when the ground line is turned on, insulation detection is performed, specifically including: 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 the first resistor to be connected between the positive bus and the ground line; obtaining a third sampling voltage formed by the first sampling module and a fourth sampling voltage formed by the second sampling module after the first resistor is connected; calculating a first insulation resistance between the positive bus and the ground line and a second insulation resistance between the negative bus and the ground line 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 the second resistor to be connected between the negative bus and the ground line; obtaining a fifth sampling voltage formed by the first sampling module and a sixth sampling voltage formed by the second sampling module after the second resistor is connected; and calculating a first insulation resistance between the positive bus and the ground line and a second insulation resistance between the negative bus and the ground line based on the first sampling voltage, the second sampling voltage, the fifth sampling voltage, and the sixth sampling voltage.

[0018] In the technical solution of the embodiment of the present application, the first resistor or the second resistor is controlled to be connected according to the magnitude of the first sampling voltage and the second sampling voltage to perform insulation detection, which can reduce errors and calculate a more accurate insulation resistance.

[0019] In a fourth aspect, the present application provides a control device for the insulation sampling circuit as described above. The control device includes: a switch control unit configured to control the connection between the withstand voltage module of the insulation sampling circuit and the ground wire, control the first switch module of the insulation sampling circuit 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; a ground wire detection unit configured to obtain a second sampling voltage formed in the second sampling module; and determine whether the ground wire is conductive based on the changing trend of the second sampling voltage; an insulation detection unit configured to perform insulation detection when the ground wire is conductive; and a fault reporting unit configured to output fault information when the ground wire is disconnected.

[0020] In the technical solution of the embodiment of the present application, the ground wire can be turned on by controlling the voltage-withstand module, making it suitable for insulation detection, and it can detect and determine whether the ground wire is actually turned on by sampling the changing trend of the voltage.

[0021] In a fifth aspect, the present application provides a battery management system. The battery management system includes: the insulation sampling circuit described above, a processor, and a memory. The memory stores computer program instructions that, when invoked by the processor, cause the processor to execute the control method described above.

[0022] In the technical solution of the embodiment of the present application, the battery management system can control the withstand voltage module to make the ground wire conductive after the withstand voltage test, making it suitable for insulation detection. In addition, it can also detect whether the ground wire is truly conductive by sampling the voltage change trend.

[0023] In a sixth aspect, the present application provides an electrical device. The electrical device includes: a battery, a load, and the battery management system described above. The battery is connected to the battery management system to supply power to the load.

[0024] In the technical solution of the embodiment of the present application, the battery management system of the electrical equipment has a high voltage resistance capability. After the voltage resistance test is completed, it can control the voltage resistance module to make the ground wire conductive, making it suitable for insulation detection, and can detect whether the ground wire is actually conductive to ensure the accuracy of the insulation detection results.

[0025] In a seventh aspect, the present application provides a computer storage medium, wherein the computer storage medium stores computer program instructions, which, when called by a processor, cause the processor to execute the control method described above.

[0026] In the technical solution of the embodiment of the present application, the computer storage medium can be set in an electronic device such as a battery management system, so that it can be suitable for insulation detection by controlling the voltage-resistant module to make the ground wire conductive after the voltage-resistant test is completed, and can detect whether the ground wire is actually conductive.

[0027] 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, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0029] Figure 1a A schematic diagram of an insulation sampling circuit according to some embodiments of the present application;

[0030] Figure 1b This is a schematic diagram of an insulation sampling circuit according to some embodiments of the present application, showing that switches are added to the positive busbar and the negative busbar to improve the withstand voltage capability;

[0031] Figure 2 A schematic diagram of a vehicle according to some embodiments of the present application;

[0032] Figure 3 This is a schematic diagram of an insulation sampling circuit according to some embodiments of the present application, showing that a voltage-resistant module is added to the ground line to improve the voltage-resistant capability;

[0033] Figure 4 A schematic diagram of an insulation sampling circuit according to some embodiments of the present application, showing the use of a controllable switch as a voltage-withstand module;

[0034] Figure 5 A flowchart of a method for controlling an insulation sampling circuit according to some embodiments of the present application;

[0035] Figure 6 This is a flow chart of a method for controlling an insulation sampling circuit according to some embodiments of the present application, showing the steps of determining whether a ground line is conductive;

[0036] Figure 7 A flowchart of a method for controlling an insulation sampling circuit according to some other embodiments of the present application;

[0037] Figure 8This is a flow chart of a method for controlling an insulation sampling circuit according to some embodiments of the present application, illustrating the steps of determining whether a first sampling circuit and a second sampling circuit have faults;

[0038] Figure 9 A flowchart of a method for controlling an insulation sampling circuit according to some embodiments of the present application, illustrating steps of calculating a first insulation resistance and a second insulation resistance;

[0039] Figure 10a A schematic diagram of an insulation sampling circuit according to some embodiments of the present application, illustrating a switch state during withstand voltage testing;

[0040] Figure 10b A schematic diagram of an insulation sampling circuit according to some embodiments of the present application, illustrating a switch state when detecting whether a first sampling circuit and a second sampling circuit have a fault;

[0041] Figure 10c This is a schematic diagram of an insulation sampling circuit according to some embodiments of the present application, illustrating the switch state when detecting whether a controllable switch is normally connected to the ground line;

[0042] Figure 10d This is a schematic diagram of an insulation sampling circuit according to some embodiments of the present application, illustrating a switch state when an insulation test is performed and a first sampling voltage is greater than or equal to a second sampling voltage;

[0043] Figure 10e This is a schematic diagram of an insulation sampling circuit according to some embodiments of the present application, illustrating a switch state when the first sampling voltage is less than the second sampling voltage during insulation detection.

[0044] Figure 11 A schematic diagram of a control device according to some embodiments of the present application;

[0045] Figure 12 Schematic diagrams of control devices according to other embodiments of the present application;

[0046] Figure 13 A schematic diagram of a battery management system according to some embodiments of the present application; DETAILED DESCRIPTION

[0047] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0049] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0050] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0051] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0052] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0053] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0054] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0055] Currently, high-voltage battery systems require insulation testing during use to prevent direct damage to the human body caused by high voltage electricity. This testing method involves controlling the connection of known resistors using relays, controllable switches, or other types of electronic switches to calculate the insulation resistance between the high-voltage positive and negative electrodes and ground.

[0056] Please refer to Figure 1a , Figure 1a Schematic diagram of the insulation sampling circuit provided in an embodiment of the present application. It mainly consists 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 of known resistance (the first resistor R1 or the second resistor R2) by controlling the switch to close. Then, based on the simultaneous equations of the sampled voltages obtained before and after the resistors are connected, the insulation resistance ( Figure 1a The resistors R p and resistor R n express).

[0057] In addition to insulation testing, high-voltage battery systems typically undergo a withstand voltage test before leaving the factory. During this withstand voltage test, a high voltage is applied between the positive busbar P+ and ground, and between the negative busbar P- and ground GND.

[0058] Understandably, Figure 1a In the insulation sampling circuit shown, the voltage applied during the withstand voltage test cannot exceed the withstand voltage of the switches used in the insulation sampling circuit (such as switch S3 or switch S4). To meet the withstand voltage test requirements, switches with higher withstand voltages can be selected. However, the withstand voltage of switches has a certain upper limit (for example, the withstand voltage limit of an optocoupler-driven MOS transistor is generally 1600V). Therefore, if the withstand voltage limit of a common switch is reached, it will be difficult to continue to meet the higher voltage withstand voltage test.

[0059] Please refer to Figure 1b , Figure 1b Schematic diagram of an insulation sampling circuit provided in an embodiment of the present application. Figure 1aCompared to the insulation sampling circuit shown in FIG, switches S+ and S- are added to the positive busbar P+ and negative busbar P-, respectively. During the withstand voltage test, switches S+ and S- are kept disconnected to improve the withstand voltage capability of the insulation sampling circuit.

[0060] However, the applicant has discovered through research that due to the presence of capacitance between the positive busbar and ground / negative busbar and ground (for example, capacitance located on the body of a new energy vehicle equipped with a high-voltage battery system), the withstand voltage module can be detected based on the trend of the sampled voltage generated by the sampling circuit. This allows the switch to be adjusted to be located on the ground line, thereby disconnecting the ground line to improve the circuit's withstand voltage capability.

[0061] Relative to Figure 1b As for the manner of setting switches on the positive busbar and the negative busbar as shown, only one switch can be used when setting a withstand voltage device on the ground wire, thereby reducing the number of switches used.

[0062] Reducing the number of switches can reduce material costs. Furthermore, since switches, as electronic components, always have a certain probability of failure, reducing the number of switches also reduces the probability of switch failure and can improve circuit reliability.

[0063] The battery management system disclosed in the embodiments of this application can be used, but is not limited to, in electrical equipment such as vehicles, ships, or aircraft. The electrical equipment includes a load that consumes electrical energy, a battery that powers the load, an insulation sampling circuit for sampling voltage, and a battery management system for managing the battery. During normal operation, the battery management system disclosed in the embodiments of this application controls the insulation sampling circuit to perform insulation testing on the electrical equipment, thereby determining the insulation condition of the electrical equipment.

[0064] For the convenience of explanation, the following embodiments are described by taking a vehicle 10 as an example of an electrical device in one embodiment of the present application. Figure 2 , Figure 2 A schematic structural diagram of a vehicle 10 provided in some embodiments of the present application.

[0065] Vehicle 10 can be a fuel-powered vehicle, a gas-powered vehicle, or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle, or an extended-range vehicle. Vehicle 10 is internally provided with a battery 11, which can be located at the bottom, front, or rear of vehicle 10. Battery 11 can be used to power vehicle 10, for example, as an operating power source for vehicle 10. Vehicle 10 can also include a controller 12 and a motor 13. Controller 12 is used to control battery 11 to power motor 13, for example, to meet the power requirements of vehicle 10 during startup, navigation, and driving.

[0066] In some embodiments of the present application, the battery 11 can serve not only as an operating power source for the vehicle 10 , but also as a driving power source for the vehicle 10 , replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 10 .

[0067] Battery 11 refers to any type of energy storage component for storing electrical energy. For example, it can be a single battery cell, a battery module composed of multiple battery cells, or a battery pack containing one or more battery modules. The shape of battery 11 can be customized based on actual needs, such as a cylinder, a rectangular parallelepiped, etc.

[0068] In some embodiments, multiple battery cells in a battery module may be connected in series, parallel, or in a hybrid configuration. A hybrid configuration refers to multiple battery cells being connected both in series and in parallel. The battery modules that comprise a battery pack may also be connected in series, parallel, or in a hybrid configuration. A battery pack or battery module may also include other structures besides battery cells, such as a busbar assembly for electrically connecting multiple battery cells.

[0069] The controller 12 includes at least one battery management system. This battery management system is an electronic system used to manage the battery 11 and ensure its normal operation. The battery management system can also be connected to an insulation sampling circuit to determine the insulation resistance between the battery's high-voltage positive terminal and the vehicle's body ground, or between the battery's high-voltage negative terminal and the vehicle's body ground, using the sampling signals generated by the insulation sampling circuit.

[0070] Before the battery leaves the factory, the insulation sampling circuit is ground-disconnected, ensuring strong voltage resistance to support withstand voltage testing. After the withstand voltage test, the insulation sampling circuit switches to ground-connected mode. Under the control of the battery management system, the insulation between the high-voltage positive and negative electrodes of battery 11 and the vehicle body ground is tested to ensure the safety of vehicle users.

[0071] According to some embodiments of this application, please refer to Figure 3 , Figure 3 A first insulation resistance R is provided between the positive busbar P+ and the ground line GND. p and capacitor C, there is a second insulation resistance R between the negative bus P- and ground GND n and capacitor C. The insulation sampling circuit includes: a first sampling circuit 100 , a second sampling circuit 200 and a voltage-resistant module 300 .

[0072] The first sampling circuit 100 includes a first switch module 110, a first resistor R1, and a first sampling module 120. The first sampling circuit 100 is connected between the positive busbar P+ and the ground line GND. The first switch module 110 controls whether the first sampling module 120 and / or the first resistor R1 are connected between the positive busbar P+ and the ground line GND. The second sampling circuit 200 includes a second switch module 210, a second resistor R2, and a second sampling module 220. The second sampling circuit 200 is connected between the negative busbar P- and the ground line. Similarly, the second switch module 210 controls whether the second sampling module 220 and / or the second resistor R2 are connected between the negative busbar - and the ground line GND.

[0073] The first sampling module 120 and the first resistor R1 are connected in parallel. The second sampling module 220 and the second resistor R2 are also connected in parallel. The first sampling module 120 and the second sampling module 220 are functional modules that form voltage sampling points. The battery management system can connect to the voltage sampling points of the first and second sampling modules and obtain the voltage signals collected by the first and second sampling circuits accordingly. The first resistor R1 and the second resistor R2 are both external resistors of known resistance. The power management system can control the switch module to connect or disconnect the first resistor R1 and the second resistor R2 to complete the insulation detection process.

[0074] The voltage-withstand module 300 is a component installed on the ground line, located between the first and second sampling circuits and the ground terminal of the ground line. By disconnecting the ground line, it improves the voltage-withstand capability of the isolated sampling circuit. The voltage-withstand module 300 can be any suitable device, as long as it can disconnect the ground line to increase the voltage resistance and has the ability to reconnect the ground line.

[0075] In some embodiments, the pressure-resistant module 300 may also be a device with only a single closing capability, wherein the initial state is disconnected and cannot be restored once it is triggered to switch to the on state.

[0076] In actual use, the withstand voltage module 300 keeps the ground wire disconnected when not in use, giving the insulation sampling circuit a strong withstand voltage capability and enabling it to complete withstand voltage tests requiring higher voltages. After the withstand voltage test, it switches to the on state to perform insulation testing under the control of the battery management system.

[0077] It should be noted that the terms "first" and "second" are used only to distinguish the different connection locations of the functional modules and are not intended to limit the specific functional modules. The first sampling circuit and the second sampling circuit may use the same circuit structure design or different circuit structure designs depending on actual needs.

[0078] One of the advantages of the insulation sampling circuit provided in the embodiment of the present application is that only a voltage-withstand module for disconnecting the ground wire needs to be added to effectively improve the voltage-withstand capability between the positive busbar and the ground wire / between the negative busbar and the ground wire, thereby meeting the needs of higher voltage voltage-withstand testing.

[0079] According to some embodiments of this application, please continue to refer to Figure 3 The first switch module 110 includes a first switch S1 and a third switch S3, and the second switch module 210 includes a second switch S2 and a fourth switch S4.

[0080] 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 line GND via a 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 line GND via a third switch S3.

[0081] Thus, the battery management system can independently control whether the first resistor R1 and the first sampling module 120 are connected to the detection circuit (i.e., between the positive bus P+ and the ground GND) by controlling the closing and opening of the first switch S1 and the third switch S3.

[0082] 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 line GND through 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 line GND through the fourth switch S4.

[0083] Therefore, the battery management system can independently control whether the second resistor R2 and the second sampling module 220 are connected to the detection circuit (i.e., between the negative bus P- and the ground GND) by controlling the closing and opening of the second switch S2 and the fourth switch S4.

[0084] The switch module of the embodiment of the present application is composed of two switches, which are used to independently control whether the sampling module and the external resistor are connected to the detection circuit, so as to facilitate the implementation of different detection steps.

[0085] According to some embodiments of this application, please continue to refer to Figure 3 The 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.

[0086] 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 line GND through the third switch S3.

[0087] Thus, the connection node between the third resistor R3 and the fifth resistor R5 connected in series forms the first voltage sampling point P1. The battery management system can be connected to the first voltage sampling point P1 to obtain the voltage signal of the first sampling circuit and perform corresponding data processing.

[0088] In addition, 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 line GND through the fourth switch S4.

[0089] Thus, the connection node between the fourth resistor R4 and the sixth resistor R6 connected in series forms the second voltage sampling point P2. The battery management system can connect to the second voltage sampling point P2, obtain the voltage signal of the second sampling circuit, and perform corresponding data processing. This design, which consists of two series-connected voltage-dividing resistors, forms a sampling module. The resistance value of the series resistor can be adjusted to meet the needs of different situations, providing the battery management system with an appropriate voltage signal.

[0090] According to some embodiments of this application, please refer to Figure 4 , the voltage-resistant module may include a controllable switch S GND It can switch between disconnected and connected states to meet the needs of both withstand voltage testing and insulation testing. In the disconnected state, the withstand voltage module can enhance the withstand voltage capability of the insulation sampling circuit. In the connected state, it can support the battery management system to perform insulation testing.

[0091] This design can disconnect the ground wire when needed, providing strong voltage resistance to meet the needs of the voltage test, and can restore the ground wire to conduction after the voltage test to meet the requirements of the insulation test.

[0092] It should be noted that the term "switch" in this embodiment refers to a device that can switch between two states: on and off. It can be implemented using appropriate electronic components, such as MOS tubes, relays, or other types of electronic switches, depending on actual needs.

[0093] According to some embodiments of the present application, the withstand voltage test method can usually be performed once before the product is officially used to ensure that the product meets the withstand voltage standard. The present application embodiment provides a withstand voltage test method. Please refer to Figure 3 During a withstand voltage test, a preset voltage is applied between the positive busbar P+ connected to the insulation sampling circuit and the ground line GND, and a preset voltage is applied between the negative busbar P- connected to the insulation sampling circuit and the ground line GND. The withstand voltage module keeps the ground line disconnected to ensure that the insulation sampling circuit has the withstand voltage capability that meets the requirements.

[0094] The preset voltage is a voltage value determined according to an actual withstand voltage test, and can be specifically determined according to actual needs.

[0095] One of the advantages of the voltage withstand test method provided in the embodiment of the present application is that a voltage withstand module is designed to disconnect the ground wire, thereby enhancing the voltage withstand capability of the insulation sampling circuit and enabling ultra-high voltage voltage withstand testing to meet the needs of actual usage.

[0096] According to some embodiments of the present application, Figure 5 This is a control method for an insulation sampling circuit provided in some embodiments of the present application. This control method can be executed by a battery management system to detect whether the withstand voltage module is normally connected and perform insulation detection accordingly. Please refer to Figure 5 , which may include the following steps:

[0097] S501 , controlling the withstand voltage module to be connected to the ground line, controlling the first switch module to connect the first sampling module between the positive bus and the ground line, and controlling the second switch module to connect the second sampling module between the negative bus and the ground line.

[0098] Among them, see Figure 4 The battery management system can simultaneously control the first switch S1, the second switch S2 and the controllable switch S by providing corresponding control signals. GND The first and second sampling modules are connected and the voltage-resistant module is connected to the ground line. The specific control signal used can be determined according to the actual situation (such as the specific switch element used in the switch module).

[0099] S502: Acquire a second sampling voltage generated by a second sampling module.

[0100] The second sampling module connected to the detection circuit will generate a corresponding voltage signal. In this embodiment, the "second sampling voltage" refers to the voltage signal generated after the second sampling module is connected to the negative bus and the ground.

[0101] S503: Determine whether the ground line is conductive based on the change trend of the second sampling voltage. If it is conductive, execute step S504; if not, execute step S505.

[0102] The “changing trend” refers to the change in the voltage value of the second sampling voltage within a certain period of time, which can be specifically represented in various ways, such as the speed of increase or decrease, the time it takes to increase or decrease to a stable value, etc.

[0103] In actual use, the withstand voltage module may fail to connect to the ground wire due to various factors, leaving the ground wire disconnected. Therefore, it is necessary to use the changing trend of the sampled voltage to help detect and determine whether the withstand voltage module has failed or malfunctioned.

[0104] S504. Perform insulation testing.

[0105] The ground wire is connected, indicating that the voltage-withstand module is not faulty and the insulation sampling circuit is normal. Therefore, the battery management system can continue with subsequent insulation testing and calculate the insulation resistance.

[0106] S505: Output fault information.

[0107] Among them, the disconnection of the ground wire indicates that the voltage-withstanding module has failed and the insulation test cannot be continued. Therefore, by outputting the fault information, the maintainer or operator is prompted to troubleshoot the fault in a timely manner. The fault information can be implemented in any suitable type.

[0108] One of the advantages of the control method provided in the embodiment of the present application is that it detects whether the ground wire is conductive based on the changing trend of the second sampling voltage, and can promptly detect failure or malfunction of the withstand voltage module, thereby greatly improving the reliability of insulation detection.

[0109] According to some embodiments of the present application, optionally, please refer to Figure 6 When the battery management system determines whether the ground wire is conductive based on the change trend, the specific steps include:

[0110] S5031. Obtain the time elapsed from the time when the voltage-resistant module is connected to the ground line to the time when the second sampling voltage reaches stability.

[0111] After the withstand voltage module is connected to the ground line, there is a process of charging the capacitance between the positive busbar and the ground / the negative busbar and the ground. Therefore, it takes a certain amount of time for the second sampling voltage to reach stability.

[0112] by Figure 4 As an example of the insulation sampling circuit shown in FIG. 1 , the first switch S1, the second switch S2 and the controllable switch S GND In the case of normal closure, there is a process of charging the capacitor C between the positive busbar and the ground / the negative busbar and the ground. Therefore, the second sampling voltage formed by the second voltage sampling point is generated from the first switch S1, the second switch S2 and the controllable switch S GND From the moment it is turned on, the voltage will change accordingly until the charging process of the capacitor is completed and then it reaches stability. Figure 4 In the figure, the equivalent capacitance C is used to represent the capacitance existing between the positive bus / negative bus and the ground.

[0113] S5032: Determine whether the elapsed time meets a preset time threshold. If so, execute step S5033; if not, execute step S5034.

[0114] The preset time threshold is a preset value, which can be determined according to actual circuit conditions to help determine whether the above-mentioned process of charging the bus capacitor exists.

[0115] S5033. Determine whether the ground wire is conductive.

[0116] If the second sampling voltage takes a long time to stabilize, it can be considered that there is a process of charging the capacitor C. Therefore, it can be determined that the withstand voltage module can be normally connected to the ground line, and the ground line is in a conducting state.

[0117] S5034. Determine whether the ground wire is not conductive.

[0118] On the contrary, when the time required for the second sampling voltage to reach stability is short, it shows that there is no charging process of the capacitor (which is inconsistent with the normal situation). Therefore, it is suggested that the withstand voltage module should not be properly connected to the ground wire, and it can be determined that the ground wire is in a non-conductive state.

[0119] One of the advantages of the method for determining whether the ground wire is conductive provided in the embodiment of the present application is that the process of charging the capacitor between the positive busbar / negative busbar and the ground is creatively utilized to detect the voltage-resistant module arranged on the ground wire, ensuring that the ground wire is in a normal conductive state when performing insulation testing.

[0120] According to some embodiments of the present application, Figure 7 This is a schematic diagram of the control method provided by some embodiments of the present application. The battery management system can execute the control method before the voltage-resistant module is connected to the ground line. Figure 7 The method steps shown are used to detect whether the sampling circuit itself has a fault or failure. Please refer to Figure 7 , the control method may include:

[0121] S701 , connect a first sampling module and a first resistor between the positive bus and the ground, and connect a second sampling module and a second resistor between the negative bus and the ground.

[0122] Among them, before the voltage-resistant module is connected to the ground wire, the battery management system can control the switch module to close by sending the corresponding control signal, so that the parallel resistor and the sampling module in the sampling circuit are connected to the detection loop (between the positive bus / negative bus and the ground wire) to detect whether there is a fault in the sampling circuit.

[0123] S702: Acquire a voltage signal generated in the first sampling module or the second sampling module.

[0124] The voltage signal may be a voltage signal formed at the first sampling module or a voltage signal formed at the second sampling module.

[0125] S703: Determine whether the first sampling circuit and / or the second sampling circuit is faulty based on the voltage signal. If so, proceed to step S704; if not, proceed to step S705.

[0126] If the specific circuit structure of the insulation sampling circuit is known, the voltage between the positive and negative busbars can be roughly inferred and calculated based on the voltage signal. This allows the presence of a fault in the sampling circuit to be determined by determining whether there is a significant difference between the theoretical and actual results, thereby improving reliability.

[0127] S704: Output fault information.

[0128] When a fault is detected in the first sampling circuit or the second sampling circuit, corresponding fault information needs to be output to prompt the user. The battery management system can output the fault information in any suitable form.

[0129] S705 , controlling the withstand voltage module to connect to the ground line, controlling the first switch module to disconnect the first resistor from between the positive bus bar and the ground line, and controlling the second switch module to disconnect the second resistor from between the negative bus bar and the ground line.

[0130] When it is detected that no fault exists, the battery management system can control the switch module to cut the first resistor and the second resistor out of the detection circuit, and prepare for the insulation detection operation step.

[0131] One of the advantages of the control method provided in the embodiment of the present application is that it is possible to detect whether there are faults in the first sampling circuit and the second sampling circuit before performing insulation detection, thereby ensuring the reliability of the insulation detection result.

[0132] According to some embodiments of this application, optionally, please continue to refer to Figure 8 When the battery management system determines whether there is a fault in the sampling circuit based on the voltage signal, it specifically includes the following steps:

[0133] S7031. Calculate the theoretical voltage difference between the positive bus and the negative bus based on the voltage signal.

[0134] The theoretical voltage value refers to the theoretical value obtained by the battery management system based on the sampled voltage obtained by the sampling module. The specific calculation process can be determined according to the specific circuit structure of the insulation sampling circuit.

[0135] S7032. Calculate the difference between the theoretical voltage difference and the actual voltage difference between the positive busbar and the negative busbar.

[0136] The actual voltage value refers to the known voltage applied between the positive busbar and the negative busbar, for example, the voltage of the battery pack connected to the positive busbar and the negative busbar.

[0137] Please refer to Figure 3 If both the first sampling circuit and the second sampling circuit are normal, it can be expected that the calculated theoretical voltage value should be roughly equivalent to the actual voltage value, and the difference between the two should not be too large. Therefore, the difference between the two can be used as a basis for determining whether the sampling circuit is normal.

[0138] 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 less than a preset difference threshold. If so, execute step S7034; if not, execute step S7035.

[0139] The difference threshold can be determined based on actual needs and is related to parameters such as the actual resistance value and battery voltage. This determination method uses the ratio of the difference between the theoretical voltage difference and the actual voltage difference as a judgment criterion to characterize the difference between the theoretical voltage difference and the actual voltage difference.

[0140] In some embodiments, other appropriate statistical methods may be selected to reflect the difference between the two.

[0141] S7033: Determine whether the first sampling circuit and the second sampling circuit have no faults.

[0142] When the result of dividing the absolute value of the difference by the voltage signal is smaller than the preset threshold, it indicates that the conditions of the first sampling circuit and the second sampling circuit are consistent with the expected conditions and there is no fault.

[0143] S7034: Determine whether the first sampling circuit and the second sampling circuit have faults.

[0144] If the division result exceeds a preset threshold, it indicates that either the first sampling circuit or the second sampling circuit differs from the expected state. This indicates that at least some of the electrical components in the first sampling circuit or the second sampling circuit are faulty and requires reporting of the fault.

[0145] Such a design can calculate the theoretical voltage difference between the positive bus and the negative bus based on the voltage signal obtained by sampling, and determine whether the first sampling circuit and the second sampling circuit are consistent with the expected normal situation based on the comparison result of the theoretical voltage difference and the actual voltage difference provided by the battery pack, thereby realizing fault detection of the first sampling circuit and the second sampling circuit.

[0146] According to some embodiments of this application, please refer to Figure 9 , Figure 9 Insulation detection methods are provided in some embodiments of the present application. This insulation detection method can be executed by a battery management system to detect the insulation resistance between the positive busbar and the ground line or between the negative busbar and the ground line. It may include the following steps:

[0147] S901 , control the first sampling module and the second sampling module to be connected, and control the withstand voltage module to be connected to the ground wire.

[0148] The battery management system can provide a corresponding control signal to the switch module to connect the first sampling module and the second sampling module, and control the withstand voltage module to connect to the ground line.

[0149] S902 : Acquire a first sampling voltage generated by a first sampling module and a second sampling voltage generated by a second sampling module respectively.

[0150] Among them, with the access of the first sampling module and the second sampling module, please refer to Figure 3 , which will form a voltage signal at the corresponding voltage sampling node and provide it to the battery management system.

[0151] 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.

[0152] If the first sampling voltage is larger, it indicates that the equivalent insulation resistance on the corresponding side is larger. Therefore, step S094 can be executed to calculate the insulation resistance by connecting the first resistor R1 to improve the accuracy of the calculation. Conversely, if the second sampling voltage is larger, it is necessary to connect the second resistor R2 for calculation.

[0153] S904 , controlling a first resistor to be connected between the positive bus and the ground line.

[0154] Among them, please refer to Figure 3 The battery management system can control the first switch S1 to be closed, so that the first resistor is connected between the positive bus and the ground line. At this time, the connected first resistor is connected in parallel with the first sampling module.

[0155] S906 , obtaining a third sampling voltage formed by the first sampling module and a fourth sampling voltage formed by the second sampling module after the first resistor is connected.

[0156] After the first resistor is connected, a parallel resistor is added to the first sampling circuit. Therefore, the voltage values ​​of the first sampling module and the second sampling module will change accordingly. In this embodiment, after the first resistor is connected, the voltage values ​​detected by the first sampling module and the second sampling module are respectively referred to as the third sampling voltage and the fourth sampling voltage, thereby distinguishing them from the first sampling voltage and the second sampling voltage detected by the first sampling module and the second sampling module before the first resistor is connected.

[0157] S908 . Calculate a first insulation resistance between the positive bus and the ground and a second insulation resistance between the negative bus and the ground according to the first sampling voltage, the second sampling voltage, the third sampling voltage, and the fourth sampling voltage.

[0158] Among them, see Figure 3 , the insulation test needs to calculate the first insulation resistance R between the positive busbar and the ground wire P and negative busbar R n If the specific configurations of the first sampling circuit and the second sampling circuit are known, the two unknown quantities, the first insulation resistance and the second insulation resistance, can be solved by combining two equations before and after the first resistor is connected.

[0159] S905 , control the second resistor to be connected between the negative bus and the ground.

[0160] Among them, please refer to Figure 3 The battery management system can control the second switch S2 to be closed, so that the second resistor R2 is connected between the positive bus and the ground line. At this time, the connected second resistor is connected in parallel with the second sampling module.

[0161] S907 , obtaining a fifth sampling voltage formed by the first sampling module and a sixth sampling voltage formed by the second sampling module after the second resistor is connected.

[0162] After the second resistor is connected, a parallel resistor is added to the second sampling circuit. Therefore, the voltage values ​​of the first sampling module and the second sampling module will change accordingly. In this embodiment, after the second resistor is connected, the voltage values ​​detected by the first sampling module and the second sampling module are referred to as 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.

[0163] S909 , calculating a first insulation resistance between the positive bus and the ground and a second insulation resistance between the negative bus and the ground according to the first sampling voltage, the second sampling voltage, the fifth sampling voltage, and the sixth sampling voltage.

[0164] Similar to step S908 above, when the specific structures of the first sampling circuit and the second sampling circuit are known, the first insulation resistance R can be solved by combining the two equations before and after the second resistor is connected. p and the second insulation resistance R n These two unknown quantities.

[0165] One of the advantages of the insulation detection method according to the embodiment of the present application is that whether to connect the first resistor or the second resistor is determined based on the magnitude relationship between the first sampling voltage and the second sampling voltage, so that a more accurate insulation resistance can be calculated.

[0166] According to some embodiments of the present application, Figures 10a to 10e This embodiment of the present application provides a schematic diagram of the insulation sampling circuit during use. Please refer to Figures 10a to 10e The 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.

[0167] The first sampling circuit 100 is comprised of a first resistor R1, a third resistor R3, a fifth resistor R5, a first switch S1, and a third switch S3. 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 line GND via the first switch S1. 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 line GND via the third switch S3. The connection node between the third resistor R3 and the fifth resistor R5 connected in series forms a first voltage sampling point P1.

[0168] In some embodiments, the first voltage sampling point P1 can be connected to an analog-to-digital conversion chip ADC. After the analog-to-digital conversion chip ADC converts the analog voltage signal into a digital signal, the voltage value in the form of a digital signal can be provided to the microcontroller MCU through an isolation communication chip.

[0169] The second resistor R2, the fourth resistor R4, the sixth resistor R6, the second switch S2, and the fourth switch S4 form 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 line GND via 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 line GND via the fourth switch S4. The connection node between the fourth resistor R4 and the sixth resistor R6 connected in series forms a second voltage sampling point P2.

[0170] In some embodiments, the second voltage sampling point P2 can be connected to an analog-to-digital conversion chip ADC. After the analog-to-digital conversion chip ADC converts the analog voltage signal into a digital signal, the voltage value in the form of a digital signal can be provided to the microcontroller MCU through an isolation communication chip.

[0171] Controllable switch S GND It is set on the ground line GND, located between the first / second sampling circuit and the ground node 3, and is used to control the ground line to be disconnected or connected.

[0172] See also Figure 10a , in the initial state, the controllable switch S GND Keep the ground wire disconnected. The insulation sampling circuit has a strong voltage resistance. Therefore, when the voltage resistance test is met, the voltage V applied between the high voltage positive electrode 1 and the ground node 3 is h , and the voltage V applied between the high voltage negative electrode 2 and the ground node 3 h .

[0173] See also Figure 10b When the battery management system detects that the vehicle is powered on at a low voltage (such as 12V) and begins to prepare for insulation testing, it controls the first switch S1, the second switch S2, the third switch S3 and the fourth switch S4 to be closed, and the controllable switch S GND The first sampling circuit and the second sampling circuit are disconnected to perform fault detection on the first sampling circuit and the second sampling circuit.

[0174] When executing the fault detection step, the battery management system can calculate the estimated voltage value U3 between the high-voltage positive electrode 1 and the high-voltage negative electrode 2 according to the second sampling voltage collected by the second sampling circuit using the following formula (1):

[0175]

[0176] Among them, U adcis the voltage value sampled by the analog-to-digital converter 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.

[0177] 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 by the following formula (2):

[0178]

[0179] When the difference X between the two is less than a preset threshold, the battery management system can determine that the first sampling circuit and the second sampling circuit are in a normal state and have no faults. When the difference X between the two is greater than or equal to the preset threshold, the battery management system can determine that there are faults in the first sampling circuit and the second sampling circuit, and it is necessary to output fault information to prompt the user to take timely action.

[0180] See also Figure 10c When the battery management system detects that there is no fault in the first sampling circuit and the second sampling circuit, the third switch S3, the fourth switch S4 and the controllable switch S GND closure.

[0181] The battery management system can control the third switch S3, the fourth switch S4 and the controllable switch S according to the second sampling voltage provided by the second sampling circuit. GND From the moment of closing until reaching stability, the rising and falling trends of the voltage are consistent with the charging process of the capacitor C between the positive bus / negative bus and the ground to detect the controllable switch S GND Whether it has been closed successfully.

[0182] In determining the controllable switch S GND If the closure is not successful, the corresponding fault information can be output to prompt the user to handle it as soon as possible. GND When the circuit is closed successfully, you can proceed to the subsequent insulation test steps.

[0183] exist Figure 10c In the switching state, the battery management system respectively obtains a first sampling voltage V1 at the first voltage sampling point P1 and a second sampling voltage V2 at the second voltage sampling point P2.

[0184] See also Figure 10dWhen the first sampling voltage V1 is greater than or equal to the second sampling voltage V2, the battery management system can control the first switch S1 to close, connecting the first resistor R1. 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 are obtained.

[0185] Finally, the first insulation resistance R between the high voltage positive electrode 1 and the ground node 3 can be calculated by the following formulas (3-1) and (3-2) respectively: p and the second insulation resistance R between the high voltage negative electrode 2 and the ground node 3 n :

[0186]

[0187]

[0188] Among them, r1 is the resistance of the first resistor R1 (which is the same as the resistance of the second resistor R2), r3 is the resistance of the third resistor R3, r4 is the resistance of the fourth resistor R4 (which is the same as the resistance of the fifth resistor R5), and r6 is the resistance of the sixth resistor R6.

[0189] See also Figure 10e When the first sampling voltage V1 is lower than the second sampling voltage V2, the battery management system can control the second switch S2 to close, connecting the second resistor R2. Then, 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 are obtained.

[0190] Finally, the first insulation resistance R between the high voltage positive electrode 1 and the ground node 3 can be calculated by the following formulas (4-1) and (4-2) respectively: p and the second insulation resistance R between the high voltage negative electrode 2 and the ground node 3 n :

[0191]

[0192]

[0193] Among them, r1 is the resistance of the first resistor R1 (which is the same as the resistance of the second resistor R2), r3 is the resistance of the third resistor R3, r4 is the resistance of the fourth resistor R4 (which is the same as the resistance of the fifth resistor R5), and r6 is the resistance of the sixth resistor R6.

[0194] According to some embodiments of this application, please refer to Figure 11 , Figure 11A control device for an insulation sampling circuit provided in an embodiment of the present application. The control device can be implemented by a battery management system and may include: a switch control unit 1110, a ground detection unit 1120, an insulation detection unit 1130, and a fault reporting unit 1140.

[0195] The switch control unit 1110 is used to control the connection between the withstand voltage module and the ground line, control the first switch module to connect the first sampling module between the positive bus and the ground line, and control the second switch module to connect the second sampling module between the negative bus and the ground line. The ground line detection unit 1120 is used to obtain the second sampled voltage formed by the second sampling module and determine whether the ground line is conductive based on the changing trend of the second sampled voltage. The insulation detection unit 1130 is used to perform insulation testing when the ground line is conductive. The fault reporting unit 1140 is used to output fault information when the ground line is disconnected.

[0196] One of the advantages of the control method provided in the embodiment of the present application is that it can detect whether the ground wire is conductive based on the change trend of the second sampling voltage, and can promptly detect the failure or malfunction of the voltage-resistant module, thereby greatly improving the reliability of insulation detection.

[0197] According to some embodiments of the present application, the insulation detection unit 1130 is optionally configured to obtain the time elapsed from the moment the withstand voltage module is connected to the ground line until the second sampled voltage reaches stability; determine whether the elapsed time meets a preset time threshold; and if so, determine that the ground line is conductive. This design creatively utilizes the process of charging the capacitor between the positive / negative busbars and the ground to detect the withstand voltage module, ensuring that the ground line is in a normal conductive state during insulation testing.

[0198] According to some embodiments of this application, please refer to Figure 12 , Figure 12 The control device of the insulation sampling circuit provided in some other embodiments of the present application. Figure 11 In addition to the functional modules shown, the system also includes a detection trigger unit 1150 , a signal acquisition unit 1160 and a fault detection unit 1170 .

[0199] The detection trigger unit 1150 is used to control the switch module to connect the first sampling module and the first resistor of the insulation sampling circuit between the positive bus and the ground line, and to connect the second sampling module and the second resistor between the negative bus and the ground line. The signal acquisition unit 1160 is used to obtain the voltage signal generated by the first sampling module or the second sampling module.

[0200] The fault detection unit 1170 is configured to determine whether a fault exists in the first sampling circuit and the second sampling circuit based on the voltage signal. The fault reporting unit 1140 is further configured to output fault information when a fault exists. The insulation detection unit 1130 is further configured to control the withstand voltage module to connect the ground line, control the first switch module to disconnect the first resistor from between the positive busbar and the ground line, and control the second switch module to disconnect the second resistor from between the negative busbar and the ground line, in preparation for performing insulation testing, when no fault exists.

[0201] This design adds a step of detecting whether the first sampling circuit and the second sampling circuit have faults before performing the insulation test, so as to ensure the reliability of the insulation test result.

[0202] According to some embodiments of the present application, the fault detection unit 1170 is optionally configured to: calculate a theoretical voltage difference between the positive bus and the negative bus based on the voltage signal; calculate the difference between the theoretical voltage difference and the actual voltage difference between the positive bus and the negative bus; and 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 less than a preset difference threshold. If so, it is determined that the first sampling circuit and the second sampling circuit are not faulty; if not, it is determined that the first sampling circuit and the second sampling circuit are faulty.

[0203] Such a design can calculate the theoretical voltage difference between the positive bus and the negative bus based on the voltage signal obtained by sampling, and determine whether the first sampling circuit and the second sampling circuit are consistent with the expected normal situation based on the comparison result of the theoretical voltage difference and the actual voltage difference provided by the battery pack, thereby realizing fault detection of the first sampling circuit and the second sampling circuit.

[0204] According to some embodiments of the present application, optionally, the insulation detection unit 1130 is specifically used to: respectively obtain a first sampling voltage formed by the first sampling module and a second sampling voltage formed by the second sampling module, and perform corresponding insulation detection steps based on a comparison result of the first sampling voltage and the second sampling voltage.

[0205] On the one hand, when the first sampling voltage is greater than or equal to the second sampling voltage, the insulation detection unit 1130 can be used to control the first resistor to be connected between the positive bus and the ground; obtain the third sampling voltage formed by the first sampling module and the fourth sampling voltage formed by the second sampling module after the first resistor is connected; and calculate the first insulation resistance between the positive bus and the ground and the second insulation resistance between the negative bus and the ground based on the first sampling voltage, the second sampling voltage, the third sampling voltage and the fourth sampling voltage.

[0206] On the other hand, when the first sampling voltage is less than the second sampling voltage, the insulation detection unit 1130 can be used to control the second resistor to be connected between the negative bus and the ground; obtain the fifth sampling voltage formed by the first sampling module and the sixth sampling voltage formed by the second sampling module after the second resistor is connected; and calculate the first insulation resistance between the positive bus and the ground and the second insulation resistance between the negative bus and the ground based on the first sampling voltage, the second sampling voltage, the fifth sampling voltage and the sixth sampling voltage.

[0207] Such a design can determine whether to connect the first resistor or the second resistor based on the magnitude relationship between the first sampling voltage and the second sampling voltage, which can make the insulation resistance result obtained by calculation more accurate.

[0208] It should be noted that in the embodiments of the present application, the functional units of the control device for the insulation sampling circuit are divided according to the method steps to be performed. In some embodiments, one or more functional units (the switch control unit, the ground detection unit, the insulation detection unit, the fault reporting unit, the detection trigger unit, the signal acquisition unit, and the fault detection unit) of the control device of the embodiments of the present application can be split into more functional units according to the actual needs to perform the corresponding method steps. In other embodiments, one or more functional units of the control device of the embodiments of the present application can also be integrated into fewer functional units to perform the corresponding method steps.

[0209] According to some embodiments of this application, please refer to Figure 13 , Figure 13 This is a schematic diagram of the structure of the battery management system provided in an embodiment of the present application. The battery management system can be applied to any type of battery or power-consuming device. Its specific implementation is not limited here.

[0210] like Figure 13 As shown, the battery management system may include: a processor 1310 , a communication interface 1320 , a memory 1330 and a communication bus 1340 .

[0211] The processor 1310, communication interface 1320, and memory 1630 communicate with each other via a communication bus 1640. The communication interface 1320 is used to connect to other devices (e.g., to the isolation sampling circuit to obtain voltage signals from the first sampling module and the second sampling module). The processor 1310 is used to call a program 1350 to execute one or more steps of the isolation sampling circuit control method described in the above embodiment. Specifically, the program 1350 may include program code or computer operating instructions.

[0212] In this embodiment, depending on the type of hardware used, processor 1310 can be a central processing unit, other general-purpose processors, digital signal processors, application-specific integrated circuits, off-the-shelf programmable gate arrays or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

[0213] The memory 1330 is used to store the program 1350. The memory 1330 may include a high-speed RAM memory, and may also include a non-volatile memory, such as at least one disk memory.

[0214] The present application also provides a computer-readable storage medium. The computer-readable storage medium may be a non-volatile computer-readable storage medium. The computer-readable storage medium stores a computer program.

[0215] When executed by a processor, the computer program implements one or more steps of the control method for the isolation sampling circuit described in the above-described embodiment. A complete computer program product is embodied on one or more computer-readable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing the computer program disclosed in the embodiments of this application.

[0216] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. An insulation sampling circuit, characterized in that: include: 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 first sampling module and / or the first resistor to be connected between the positive bus and the ground line; 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 second sampling module and / or the second resistor to be connected between the negative bus and the ground line; A pressure-resistant module provided on the ground line, the pressure-resistant module being used to disconnect the ground line; The first switch module includes: a first switch and a third switch; the second switch module includes: a second switch and a fourth switch; Wherein, one end of the first resistor is connected to the positive bus, and the other end of the first resistor is connected to the ground line through a first switch; One end of the first sampling module is connected to the positive bus, and the other end of the first sampling module is connected to the ground line through a third switch; One end of the second resistor is connected to the negative bus, and the other end of the second resistor is connected to the ground line through a second switch; One end of the second sampling module is connected to the negative bus, and the other end of the second sampling module is connected to the ground line through the fourth switch; The first sampling module includes: a third resistor and a fifth resistor; the second sampling module includes: a fourth resistor and a sixth resistor; One end of the third resistor is connected to the positive bus, 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 line through 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 bus, 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 line through the fourth switch, and a connection node between the fourth resistor and the sixth resistor forms a second voltage sampling point.

2. The insulation sampling circuit according to claim 1, characterized in that: The voltage-resistant module includes a controllable switch arranged on a ground line.

3. A withstand voltage test method, applied to the insulation sampling circuit according to any one of claims 1-2, characterized in that: include: Applying a preset voltage between the positive busbar connected to the insulation sampling circuit and the ground line, and applying a preset voltage between the negative busbar connected to the insulation sampling circuit and the ground line; Wherein, the withstand voltage module of the insulation sampling circuit keeps the ground line disconnected.

4. A control method for an insulation sampling circuit according to any one of claims 1 to 2, characterized in that: include: Controlling the withstand voltage module of the insulation sampling circuit to be connected to the ground line, controlling the first switch module of the insulation sampling circuit to connect the first sampling module between the positive bus and the ground line, and controlling the second switch module to connect the second sampling module between the negative bus and the ground line; Acquire a second sampling voltage formed by a second sampling module; determining whether the ground wire is conductive according to a change trend of the second sampling voltage; When the ground wire is conductive, performing insulation detection; When the ground line is disconnected, fault information is output.

5. The control method according to claim 4, characterized in that: The determining, according to the change trend of the second sampling voltage, whether the ground line is conductive specifically includes: Obtaining the time elapsed from the time when the voltage-resistant module is connected to the ground wire to the time when the second sampling voltage reaches stability; Determining whether the elapsed time meets a preset time threshold; If so, it is determined that the ground line is conductive.

6. The control method according to claim 4, characterized in that: Before controlling the voltage-resistant module to be connected to the ground line, the method further includes: Connecting the first sampling module and the first resistor of the insulation sampling circuit between the positive bus and the ground, and connecting the second sampling module and the second resistor between the negative bus and the ground; Acquiring a voltage signal generated by the first sampling module or the second sampling module; determining, based on the voltage signal, whether the first sampling circuit and the second sampling circuit are faulty; When a fault occurs, output fault information; When there is no fault, the withstand voltage module is controlled to connect the ground line, the first switch module is controlled to cut the first resistor out from between the positive bus and the ground line, and the second switch module is controlled to cut the second resistor out from between the negative bus and the ground line.

7. The control method according to claim 6, characterized in that: The determining, based on the voltage signal, whether the first sampling circuit and the second sampling circuit have faults specifically includes: Calculating a theoretical voltage difference between the positive bus and the negative bus according to the voltage signal; Calculating a difference between the theoretical voltage difference and the actual voltage difference between the positive busbar and the negative busbar; Determining whether a ratio between an absolute value of a difference between the theoretical voltage difference and the actual voltage difference and the actual voltage difference is less than a preset difference threshold; If so, determining that the first sampling circuit and the second sampling circuit are not faulty; If not, it is determined that the first sampling circuit and the second sampling circuit are faulty.

8. The control method according to claim 6, characterized in that: When the ground wire is conductive, performing insulation detection specifically 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 the first resistor to be connected between the positive bus and the ground; acquiring a third sampling voltage formed by the first sampling module and a fourth sampling voltage formed by the second sampling module after the first resistor is connected; Calculating a first insulation resistance between the positive bus and the ground and a second insulation resistance between the negative bus and the ground according to 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 the second resistor to be connected between the negative bus and the ground; acquiring a fifth sampling voltage formed by the first sampling module and a sixth sampling voltage formed by the second sampling module after the second resistor is connected; A first insulation resistance between the positive bus bar and the ground and a second insulation resistance between the negative bus bar and the ground are calculated based on the first, second, fifth, and sixth sampling voltages.

9. A control device for an insulation sampling circuit according to any one of claims 1 to 2, characterized in that: The control device comprises: a switch control unit, configured to control the voltage-withstand module of the insulation sampling circuit to be connected to the ground line, control the first switch module of the insulation sampling circuit to connect the first sampling module between the positive bus and the ground line, and control the second switch module to connect the second sampling module between the negative bus and the ground line; a ground line detection unit, configured to obtain a second sampling voltage formed in the second sampling module; and determine whether the ground line is conductive based on a change trend of the second sampling voltage; an insulation detection unit, used for performing insulation detection when the ground wire is conductive; A fault reporting unit is used to output fault information when the ground wire is disconnected.

10. A battery management system, characterized in that: include: A processor and a memory; the memory stores computer program instructions, and when the computer program instructions are called by the processor, the processor executes the control method according to any one of claims 4 to 7.

11. An electrical device, characterized in that: include: The insulation sampling circuit according to any one of claims 1-2, a battery, a load, and the battery management system according to claim 10; the battery is connected to the battery management system to power the load.

12. A computer storage medium, characterized in that The computer storage medium stores computer program instructions; when the computer program instructions are called by the processor, the processor executes the control method according to any one of claims 4 to 7.

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