Detection circuit, detection method, system, battery pack and electric drive device

Abstract

The present application discloses a detection circuit, a detection method, a system, a battery pack, and an electric drive device. The detection circuit includes: a current source circuit connected to the first end of an interlocking loop to form a first current branch, and the current source circuit is also connected to the second end of the interlocking loop to form a second current branch; a processing circuit includes a first sampling end and a second sampling end, configured to obtain a first voltage collected when the first current branch is working through the first sampling end, and obtain a second voltage collected when the second current branch is working through the second sampling end, and determine the resistance of the interlocking loop based on the voltage difference between the first voltage and the second voltage and the current value output by the current source circuit; wherein the resistance of the interlocking loop is used to determine whether there is an abnormality in the interlocking loop. This not only solves the problem of being unable to obtain the interlocking connection status when a short-to-ground fault occurs, but also reduces misdiagnosis caused by leakage current and improves the reliability of the interlocking loop.

Description

Technical Field

[0001] The present application relates to the field of high-voltage interlocking technology, and in particular to a detection circuit, a detection method, a system, a battery pack, and an electric drive device. Background Art

[0002] With the increasing popularity of new energy vehicles, the battery management system (BMS) and its operational stability have become a major concern for users. If the operating system fails to properly read or identify the high-voltage interlock status, it could have an immeasurable impact on users and even lead to serious safety incidents.

[0003] To address high-voltage safety issues, common solutions include using voltage- or current-type high-voltage interlocks. These methods, such as detecting resistor voltage dividers or voltage drops across resistors, or other detection methods, are often used for diagnosis. However, these solutions are still not ideal and cannot accurately determine the current interlock connection status of the high-voltage connector. They may even result in false alarms of high-voltage interlock faults. Summary of the Invention

[0004] The present application proposes a detection circuit, a detection method, a system, a battery pack, and an electric drive device.

[0005] The technical solution of this application is achieved as follows:

[0006] In a first aspect, an embodiment of the present application provides a detection circuit, wherein the detection circuit is connected to an interlocking loop, the detection circuit includes a current source circuit and a processing circuit, the current source circuit is connected to a first end of the interlocking loop to form a first current branch, and the current source circuit is further connected to a second end of the interlocking loop to form a second current branch; wherein:

[0007] The processing circuit includes a first sampling terminal and a second sampling terminal, the first sampling terminal is connected to the first terminal of the interlocking loop, and the second sampling terminal is connected to the second terminal of the interlocking loop;

[0008] The processing circuit is configured to obtain, through a first sampling terminal, a first voltage collected when the first current branch is operating, and obtain, through a second sampling terminal, a second voltage collected when the second current branch is operating, and determine a resistance value of an interlocking loop based on a voltage difference between the first voltage and the second voltage and a current value output by the current source circuit; wherein the resistance value of the interlocking loop is used to determine whether there is an abnormality in the interlocking loop; wherein:

[0009] When the current source circuit includes a first current source, the detection circuit further includes a switching circuit, the switching circuit includes a first switching element and a second switching element, and the first current source, the first switching element, and a first end of the interlock loop are connected to form a first current branch, and the first current source, the second switching element, and a second end of the interlock loop are connected to form a second current branch;

[0010] or,

[0011] When the current source circuit includes a first current source and a second current source, the first current source is connected to the first end of the interlocking loop to form a first current branch, the second current source is connected to the second end of the interlocking loop to form a second current branch, and the first current source and the second current source do not work at the same time.

[0012] Through the above technical means, regardless of whether the current source circuit includes a first current source or a first current source and a second current source, the current directions of the first current branch and the second current branch when flowing through the interlock loop are opposite. That is, by adding a second current branch (e.g., a reverse current injection loop) with a current direction opposite to that of the first current branch to the detection circuit, bidirectional sampling detection for both forward and reverse current injection is achieved. The resistance of the interlock loop is determined based on the voltage difference between the collected first and second voltages and the current value output by the current source circuit. In this way, bidirectional sampling detection not only solves the problem of being unable to obtain the interlock connection status when a short-to-ground fault occurs, but also improves sampling accuracy, significantly reducing misdiagnosis caused by leakage current. After determining the resistance of the interlock loop through bidirectional sampling detection, the current interlock state in the loop can also be determined, such as whether the current interlock connection is reliable or whether the current interlock is loose or has poor contact, thereby improving the reliability of the interlock loop.

[0013] In some embodiments, when the current source circuit includes a first current source, the detection circuit is configured to inject a forward current into the interlocking loop based on the first current branch when the first switching element is turned on and the second switching element is turned off, and obtain the collected first voltage through the first sampling end; and the detection circuit is also configured to inject a reverse current into the interlocking loop based on the second current branch when the first switching element is turned off and the second switching element is turned on, and obtain the collected second voltage through the second sampling end.

[0014] Through the above-mentioned technical means, due to the presence of the first switching element and the second switching element, and the first switching element is located on the first current branch and the second switching element is located on the second current branch, it is possible to achieve the first current branch and the second current branch working at different times; in this way, by controlling the closing status of the first switching element and the second switching element to change the current injection direction, bidirectional sampling of forward current injection and reverse current injection can be achieved, which not only solves the problem of being unable to sample normally to determine the current interlocking connection status when a short-to-ground fault occurs, but also can realize leakage current compensation through two samplings, solves the accuracy deviation caused by the leakage current, thereby improving the sampling accuracy and greatly reducing the misjudgment rate caused by the influence of leakage current.

[0015] In some embodiments, when the current source circuit includes a first current source and a second current source, the first current source includes a first enable terminal, and the first enable terminal is used to receive a first enable signal; the second current source includes a second enable terminal, and the second enable terminal is used to receive a second enable signal; the detection circuit is configured to inject a forward current into the interlocking loop based on the first current branch when the first enable signal is in a first level state and the second enable signal is in a second level state, and obtain the collected first voltage through the first sampling terminal; and the detection circuit is also configured to inject a reverse current into the interlocking loop based on the second current branch when the first enable signal is in a second level state and the second enable signal is in a first level state, and obtain the collected second voltage through the second sampling terminal.

[0016] Through the above-mentioned technical means, since the first current source is located on the first current branch and the second current source is located on the second current branch, the two current sources can also be used to achieve the first current branch and the second current branch working at different times; in this way, by controlling the enabling status of the two current sources to change the current injection direction, bidirectional sampling of forward current injection and reverse current injection can be achieved, which not only solves the problem of being unable to sample normally to determine the current interlocking connection status when a short-to-ground fault occurs, but also solves the accuracy deviation caused by leakage current, thereby improving the sampling accuracy; using two current sources at the same time can also improve system stability.

[0017] In some embodiments, when the current source circuit includes a first current source and a second current source, the detection circuit also includes a switching circuit, wherein: the switching circuit includes a third switching element and a fourth switching element, and the first current source, the third switching element and the first end of the interlocking loop are connected to form a first current branch, and the second current source, the fourth switching element and the second end of the interlocking loop are connected to form a second current branch.

[0018] Through the above technical means, the third switching element is located in the first current branch, and the fourth switching element is located in the second current branch. By controlling the on and off of the third and fourth switching elements, the current injection direction can also be controlled, enabling bidirectional sampling of forward and reverse current injection. This not only solves the problem of being unable to obtain the interlock connection status during a short-to-ground fault, but also improves sampling accuracy. The use of two current sources also improves system stability.

[0019] In some embodiments, the detection circuit is configured to inject a forward current into the interlocking loop based on the first current branch when the third switching element is turned on and the fourth switching element is turned off, and obtain the collected first voltage through the first sampling end; and the detection circuit is also configured to inject a reverse current into the interlocking loop based on the second current branch when the third switching element is turned off and the fourth switching element is turned on, and obtain the collected second voltage through the second sampling end.

[0020] Through the above-mentioned technical means, due to the presence of the third switching element and the fourth switching element, and the first current source and the third switching element are located on the first current branch, and the second current source and the fourth switching element are located on the second current branch, it is possible to achieve the first current branch and the second current branch working at different times; in this way, the working states of the two current sources are switched by controlling the closing conditions of the third switching element and the fourth switching element, and the current injection direction is changed by switching the working states of the current sources, which not only solves the problem that normal sampling cannot be performed to determine the current interlocking connection state when a short-to-ground fault occurs, but also realizes leakage current compensation through two samplings, solves the accuracy deviation caused by the leakage current, thereby improving the sampling accuracy and greatly reducing the misjudgment rate caused by the influence of leakage current; at the same time, it can continue to sample when a single current source fails, thereby improving system stability.

[0021] In some embodiments, the detection circuit further includes a grounding resistor, a first end of the grounding resistor is connected to the second end of the interlock loop, and a second end of the grounding resistor is connected to the ground.

[0022] Through the above technical means, the second end of the interlocking loop can be connected to the ground through the grounding resistor, so that the static electricity, leakage or fault current that may accumulate in the detection circuit can be introduced into the ground through the grounding resistor, preventing electric shock hazards and equipment damage.

[0023] In a second aspect, an embodiment of the present application provides a detection method, which is applied to the detection circuit as described in the first aspect, and the detection circuit is connected to an interlocking loop; the detection method includes:

[0024] Acquire a first voltage acquired when the first current branch is operating and a second voltage acquired when the second current branch is operating;

[0025] determining a voltage difference between the first voltage and the second voltage;

[0026] The resistance of the interlocking loop is determined based on the voltage difference and the current value output by the current source circuit; wherein the resistance of the interlocking loop is used to determine whether there is an abnormality in the interlocking loop.

[0027] Through the above technical means, after obtaining a first voltage sampled from the first current branch and a second voltage sampled from the second current branch, the voltage difference between the first and second voltages is determined. Then, based on the voltage difference and the current value output by the current source circuit, the resistance of the interlock circuit is determined. The resistance of the interlock circuit is used to determine whether there is an abnormality in the interlock circuit. In this way, because the currents of the first and second current branches flow in opposite directions when passing through the interlock circuit, bidirectional sampling and detection based on forward and reverse current injection (e.g., the obtained first and second voltages) not only solves the problem of being unable to determine the interlock connection status when a short-to-ground fault occurs, but also improves sampling accuracy, significantly reducing misdiagnosis caused by leakage current. Furthermore, after determining the resistance of the interlock circuit based on bidirectional sampling and detection, the current interlock status in the circuit can also be determined, such as whether the current interlock connection is reliable or whether the current interlock is loose or has poor contact, thereby improving the reliability of the interlock circuit.

[0028] In some embodiments, the current source circuit includes a first current source, and the detection circuit further includes a first switching element and a second switching element; obtaining a first voltage collected when the first current branch is operating and a second voltage collected when the second current branch is operating includes:

[0029] When the first switch element is turned on and the second switch element is turned off, a forward current is injected into the interlock loop based on the first current branch, and a first voltage is acquired through the first sampling terminal; and

[0030] When the first switch element is turned off and the second switch element is turned on, a reverse current is injected into the interlock loop based on the second current branch, and the collected second voltage is obtained through the second sampling terminal.

[0031] Through the above-mentioned technical means, the presence of the first and second switching elements enables the first and second current branches to operate at different times. By controlling the on / off conditions of the first and second switching elements to change the current injection direction, bidirectional sampling of both forward and reverse current injection is achieved. This not only resolves the issue of being unable to properly sample and determine the current interlock connection status during a short-to-ground fault, but also compensates for leakage current through two sampling steps, addressing the accuracy deviation caused by leakage current, thereby improving sampling accuracy and significantly reducing the misjudgment rate caused by leakage current.

[0032] In some embodiments, the current source circuit includes a first current source and a second current source, wherein the first current source includes a first enable terminal and the second current source includes a second enable terminal; obtaining a first voltage collected when the first current branch is operating and a second voltage collected when the second current branch is operating includes:

[0033] When the first enable signal received by the first enable terminal is in a first level state and the second enable signal received by the second enable terminal is in a second level state, injecting a forward current into the interlock loop based on the first current branch, and acquiring the collected first voltage through the first sampling terminal; and

[0034] When the first enable signal received by the first enable terminal is in the second level state and the second enable signal received by the second enable terminal is in the first level state, a reverse current is injected into the interlock loop based on the second current branch, and the collected second voltage is obtained through the second sampling terminal.

[0035] Through the above-mentioned technical means, since the first current source is located on the first current branch and the second current source is located on the second current branch, the two current sources can also be used to achieve the first current branch and the second current branch working at different times; in this way, by controlling the enabling status of the two current sources to change the current injection direction, bidirectional sampling of forward current injection and reverse current injection can be achieved, which not only solves the problem of being unable to sample normally to determine the current interlocking connection status when a short-to-ground fault occurs, but also solves the accuracy deviation caused by the leakage current, thereby improving the sampling accuracy; using two current sources at the same time can also improve system stability.

[0036] In some embodiments, the current source circuit includes a first current source and a second current source, and the detection circuit further includes a third switch element and a fourth switch element; obtaining a first voltage collected when the first current branch is operating and a second voltage collected when the second current branch is operating includes:

[0037] When the third switch element is turned on and the fourth switch element is turned off, a forward current is injected into the interlock loop based on the first current branch, and a first voltage is acquired through the first sampling terminal; and

[0038] When the third switch element is turned off and the fourth switch element is turned on, a reverse current is injected into the interlock loop based on the second current branch, and the collected second voltage is obtained through the second sampling terminal.

[0039] Through the above-mentioned technical means, due to the presence of the third switching element and the fourth switching element, and the first current source and the third switching element are located on the first current branch, and the second current source and the fourth switching element are located on the second current branch, it is also possible to achieve the first current branch and the second current branch working at different times; in this way, the working states of the two current sources are switched by controlling the closing conditions of the third switching element and the fourth switching element, and the current injection direction is changed by switching the working states of the current sources, which not only solves the problem that normal sampling cannot be performed to determine the current interlocking connection state when a short-to-ground fault occurs, but also realizes compensation for leakage current through two samplings, solves the accuracy deviation caused by leakage current, thereby improving the accuracy of sampling and greatly reducing the misjudgment rate caused by the influence of leakage current; at the same time, sampling can continue when a single current source fails, thereby improving system stability.

[0040] In a third aspect, an embodiment of the present application provides a battery management system, which includes an interlocking loop and a circuit board, wherein the circuit board includes the detection circuit as described in the first aspect.

[0041] In a fourth aspect, an embodiment of the present application provides a battery pack, which includes a battery and a battery management system as described in the third aspect.

[0042] In a fifth aspect, an embodiment of the present application provides an electric drive device, which includes a battery management system as described by the third party, or a battery pack as described in the fourth aspect.

[0043] It should be understood that the above general description and the following detailed description are merely exemplary and explanatory, and do not limit the technical solutions of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 A schematic diagram of the structure of a detection circuit provided in an embodiment of the present application Figure 1 ;

[0045] Figure 2 A schematic diagram of the structure of a detection circuit provided in an embodiment of the present application Figure 2 ;

[0046] Figure 3 A schematic diagram of the structure of a detection circuit provided in an embodiment of the present application Figure 3 ;

[0047] Figure 4 A schematic diagram of the structure of a detection circuit provided in an embodiment of the present application Figure 4 ;

[0048] Figure 5 A schematic diagram of the structure of a detection circuit provided in an embodiment of the present application Figure 5;

[0049] Figure 6 A schematic diagram of the structure of a detection circuit provided in an embodiment of the present application Figure 6 ;

[0050] Figure 7 A schematic diagram of the structure of a detection circuit provided in an embodiment of the present application Figure 7 ;

[0051] Figure 8 A schematic diagram of the structure of a detection circuit provided in an embodiment of the present application Figure 8 ;

[0052] Figure 9 A schematic diagram of the structure of a detection circuit provided in an embodiment of the present application Figure 9 ;

[0053] Figure 10 A schematic diagram of a detection method provided in an embodiment of the present application;

[0054] Figure 11 A schematic diagram of the structure of a detection system provided in an embodiment of the present application;

[0055] Figure 12 A schematic diagram of an application scenario of a detection system provided in an embodiment of the present application;

[0056] Figure 13 A schematic diagram of the structure of a battery management system provided in an embodiment of the present application;

[0057] Figure 14 A schematic diagram of the composition structure of a battery pack provided in an embodiment of the present application. DETAILED DESCRIPTION

[0058] In order to enable a more detailed understanding of the features and technical contents of the embodiments of the present application, the implementation of the embodiments of the present application is described in detail below with reference to the accompanying drawings. The attached drawings are for reference only and are not used to limit the embodiments of the present application.

[0059] 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 pertains. The terms used herein are for the purpose of describing the embodiments of this application only and are not intended to limit this application.

[0060] In the following description, reference is made to “some embodiments”, which describes a subset of all possible embodiments, but it will be understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0061] It should also be pointed out that the terms "first\second\third" involved in the embodiments of the present application are only used to distinguish similar objects and do not represent a specific ordering of the objects. It can be understood that "first\second\third" can be interchanged with a specific order or sequence where permitted, so that the embodiments of the present application described here can be implemented in an order other than that illustrated or described here.

[0062] In addition, references to "embodiments" herein 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 such phrases in various places in the specification does not necessarily refer to the same embodiment, nor does it necessarily refer to independent or alternative embodiments that are 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.

[0063] The following is an introduction to the relevant terms and technologies of this application.

[0064] The Battery Management System (BMS) is an indispensable core technology in the battery system. It is a device that monitors the status of energy storage batteries. Its main function is to intelligently manage and maintain each battery cell to ensure the safe use of the battery during the charging and discharging process.

[0065] The Microprogrammed Control Unit (MCU), also known as a "microcontroller" or simply a "microprocessor", is the core control part of the BMS, responsible for signal detection and command control.

[0066] The Battery Management Unit (BMU) is the main control board that controls the relays in the high-voltage box and collects information such as temperature and current in the high-voltage box.

[0067] A voltage stabilizer is a component used to maintain voltage stability. The resistance of the voltage stabilizer changes with the load and input voltage to achieve a stable output voltage.

[0068] The High Voltage Interlock Loop (HVIL), also known as "high voltage interlock," is a safety mechanism that uses low-voltage signals to check the integrity and continuity of the entire high-voltage system circuit, identify abnormal circuit disconnections, and promptly disconnect the control components at the high-voltage input. Simply put, the high-voltage circuit's continuity (danger) is checked by the low-voltage circuit's on / off signal (safety).

[0069] New energy batteries are being used more and more widely in life and industry. For example, new energy vehicles equipped with batteries have been widely used. In addition, batteries are also being increasingly used in energy storage fields.

[0070] Currently, new energy batteries are increasingly being used in everyday life and industry. They are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but are also widely used in electric vehicles like electric bicycles, electric motorcycles, and electric cars, as well as in a variety of fields such as aerospace. As the application of power batteries continues to expand, market demand is also growing.

[0071] In the embodiments of the present application, the battery may be a battery cell, or may be a battery pack (Pack) composed of multiple battery cells. A battery cell refers to a basic unit that can realize the mutual conversion of chemical energy and electrical energy, and can be used to make a battery module or a battery pack, thereby being used to supply power to an electrical device. A battery cell may be a secondary battery, which refers to a battery cell that can be recharged to activate the active material after the battery cell is discharged and continue to be used. The battery cell may be a lithium-ion battery, a sodium-ion battery, a sodium-lithium-ion battery, a lithium metal battery, a sodium metal battery, a lithium-sulfur battery, a magnesium-ion battery, a nickel-hydrogen battery, a nickel-cadmium battery, a lead-acid battery, etc., and this is not limited here.

[0072] In the embodiment of the present application, the battery may also be a single physical module including one or more battery cells to provide higher voltage and capacity. When there are multiple battery cells, the multiple battery cells are connected in series, in parallel or in hybrid via a busbar.

[0073] With the widespread application of batteries in power batteries and energy storage, the replacement of fuel vehicles with new energy vehicles (such as electric vehicles) has become a trend in the automotive industry. The safety of new energy vehicles is receiving increasing attention. The primary difference between new energy vehicles and traditional vehicles is that they rely on high voltage and high current for power. Therefore, high-voltage safety considerations are crucial in their design. A common high-voltage circuit safety monitoring system is the high-voltage interlock circuit, which primarily monitors the continuity of various high-voltage components in the vehicle. Based on this monitoring, the vehicle controller decides whether to disconnect the high-voltage circuit to maintain a safe state.

[0074] As new energy vehicles become increasingly popular, the stability of the BMS and its operation remains a major concern for users. If the operating system fails to properly read or identify the high-voltage interlock status, it could have an immeasurable impact on users and even lead to serious safety accidents. One of the risks of high-voltage electrical systems is a sudden power outage, resulting in a loss of vehicle power. The high-voltage interlock not only monitors the possibility of a natural loosening of the high-voltage circuit, providing an alarm to the vehicle controller before the high-voltage power is lost, allowing the vehicle system time to take countermeasures, but also prevents human error, preventing manual disconnection from applying the full circuit voltage across the breakpoint, potentially breaking the air and causing an arc.

[0075] To ensure high-voltage system safety, common solutions in related technologies use voltage-type or current-type high-voltage interlocks, which perform diagnosis by detecting resistor voltage divider or voltage drop across resistors, or pulse width modulation (PWM) detection. However, these methods cannot determine whether the current high-voltage connector is properly connected after one of the high-voltage interlock pins (PINs) is shorted to ground. When there is leakage current in the loop, a false high-voltage interlock fault may be reported.

[0076] In order to solve the above-mentioned drawbacks, the embodiments of the present application provide a detection circuit, a detection method, a system, a battery pack and an electric drive device, wherein the detection circuit is connected to the interlocking loop. By adding a reverse current injection loop in the detection circuit, bidirectional sampling detection of forward current injection and reverse current injection can be achieved, and the resistance of the interlocking loop is determined according to the voltage difference between the collected first voltage and the second voltage and the current value output by the current source circuit. In this way, not only can the problem of being unable to obtain the interlocking connection status when a short-to-ground fault occurs be solved, but the accuracy of sampling can also be improved, and the misdiagnosis caused by the influence of leakage current can be greatly reduced; after the resistance of the interlocking loop is determined based on the bidirectional sampling detection, the current state of the interlocking in the loop can also be judged, such as whether the current interlocking connection is reliable or whether the current interlocking is loose or has poor contact, thereby improving the reliability of the interlocking loop.

[0077] The various embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0078] In one embodiment of the present application, Figure 1 A schematic diagram of the structure of a detection circuit provided in an embodiment of the present application Figure 1 .like Figure 1 As shown, the detection circuit 10 is connected to the interlock loop 20. The detection circuit 10 may include a current source circuit 101 and a processing circuit 102. The current source circuit 101 is connected to a first end of the interlock loop 20 to form a first current branch. The current source circuit 101 is also connected to a second end of the interlock loop 20 to form a second current branch.

[0079] The processing circuit 102 includes a first sampling terminal ADC1 and a second sampling terminal ADC2, wherein the first sampling terminal ADC1 is connected to the first terminal of the interlock loop 20, and the second sampling terminal ADC2 is connected to the second terminal of the interlock loop 20;

[0080] The processing circuit 102 is configured to obtain a first voltage collected when the first current branch is operating through the first sampling terminal ADC1, obtain a second voltage collected when the second current branch is operating through the second sampling terminal ADC2, and determine the resistance of the interlocking loop 20 based on the voltage difference between the first voltage and the second voltage and the current value output by the current source circuit 101; wherein the resistance of the interlocking loop 20 is used to determine whether there is an abnormality in the interlocking loop 20.

[0081] In the embodiment of the present application, the current source circuit 101 can stably output a rated current value, and the current direction of the current value when flowing through the first current branch and the second current branch through the interlock loop 20 is opposite. For example, the first current branch can be a branch for positive current injection, and the second current branch can be a branch for negative current injection; or, the first current branch can be a branch for negative current injection, and the second current branch can be a branch for positive current injection.

[0082] In a specific implementation, Figure 1 For example, the direction of the positive current injection can be defined as the direction of the current flowing from the first end of the interlock loop 20 to the second end of the interlock loop 20, and the direction of the negative current injection can be defined as the direction of the current flowing from the second end of the interlock loop 20 to the first end of the interlock loop 20. In this implementation, the first current branch is the branch for the positive current injection, and the second current branch is the branch for the negative current injection.

[0083] In the embodiment of the present application, the processing circuit 102 may be a microprocessor or an MCU, which has signal acquisition and signal processing functions. The processing circuit 102 includes two sampling terminals (e.g., a first sampling terminal ADC1 and a second sampling terminal ADC2). The first sampling terminal ADC1 is used to acquire a first voltage acquired when the first current branch is operating, and the second sampling terminal ADC2 is used to acquire a second voltage acquired when the second current branch is operating.

[0084] It should be noted that a reverse detection injection branch is added to the detection circuit 10, and the collected first voltage and second voltage can be obtained by using two different current injection directions; the resistance of the interlocking loop 20 can be determined according to the voltage difference between the first voltage and the second voltage and the current value output by the current source circuit 101, thereby avoiding the occurrence of short-to-ground faults or weakening the influence of leakage current on the sampling accuracy.

[0085] In addition, in the embodiment of the present application, the interlocking circuit 20 is applied to a high voltage scenario, so the interlocking circuit can also be called a "high voltage interlocking circuit". In this field, the concepts of high voltage and low voltage are relative. For example, if the voltage of the device to the ground is 1000V or less, it can be called low voltage; if the voltage of the device to the ground is above 1000V, it can be called high voltage. Here, high voltage can also be called "high voltage", which usually refers to bus voltage, battery voltage, etc. above 1000V, and is not specifically limited here.

[0086] It should also be noted that the interlock circuit 20 can be used to indicate whether there is an abnormality in the connection of the high-voltage connector in the high-voltage interlock circuit. Specifically, this can be determined based on the resistance value of the interlock circuit 20. Thus, after determining the resistance value of the interlock circuit 20, it is possible to determine the current state of the interlock in the circuit, for example, whether the current interlock connection is reliable or unreliable, such as a loose connection or poor contact.

[0087] That is, in the embodiment of the present application, the detection circuit 10 is connected to the interlocking loop 20, and a second current branch (e.g., a reverse current injection loop) having a current direction opposite to that of the first current branch is added to the detection circuit 10, thereby enabling bidirectional sampling detection of forward current injection and reverse current injection, and determining the resistance of the interlocking loop based on the voltage difference between the collected first voltage and the second voltage and the current value output by the current source circuit. In this way, based on the bidirectional sampling detection, not only can the problem of being unable to obtain the interlocking connection status when a short-to-ground fault occurs be solved, but the sampling accuracy can also be improved, significantly reducing misdiagnosis caused by leakage current. After determining the resistance of the interlocking loop based on the bidirectional sampling detection, it is also possible to determine the current state of the interlock in the loop, such as whether the current interlocking connection is reliable or whether the current interlock is loose or has poor contact, thereby improving the reliability of the interlocking loop.

[0088] In some embodiments, Figure 1 The detection circuit 10 is shown based on Figure 2 The detection circuit 10 may further include a grounding resistor R1 , wherein a first end of the grounding resistor R1 is connected to a second end of the interlocking loop 20 , and a second end of the grounding resistor R1 is connected to the ground GND.

[0089] In the present application, grounding refers to establishing a good connection between the metal components of a device or circuit and the ground through a conductive method to ensure the safety of people and equipment. This process fully utilizes the conductivity of the ground, directing current into the ground, and quickly dissipating it through the underground conductor to the ground.

[0090] In an embodiment of the present application, the second end of the interlocking loop 20 can be connected to the ground GND through the grounding resistor R1, so that static electricity, leakage or fault current that may accumulate in the detection circuit can be introduced into the ground through the grounding resistor R1, thereby preventing electric shock hazards and equipment damage.

[0091] It should be noted that the value range of the grounding resistor R1 should be selected according to the specific application scenario and circuit requirements. For example, the value of the grounding resistor R1 can be in the hundreds of ohms level, but this is not limited here.

[0092] It is understandable that the current source circuit 101 may include one current source or two current sources. When the current source circuit 101 includes only one current source, the current source may be used to provide a current branch for forward injection and a current branch for reverse injection for the interlocking loop. When the current source circuit 101 includes two current sources, the two current sources may be used to provide a current branch for forward injection and a current branch for reverse injection for the interlocking loop, respectively.

[0093] In one possible implementation, Figure 2 The detection circuit 10 is shown based on Figure 3 The current source circuit 101 may include a first current source U1. At this time, the first current source U1 is connected to the first end of the interlock loop 20 to form a first current branch, and the first current source U1 is also connected to the second end of the interlock loop 20 to form a second current branch.

[0094] In some embodiments, see Figure 3 The current source circuit 101 may further include a first current limiting resistor R2 , and the first current limiting resistor R2 is connected to the output end of the first current source U1 .

[0095] In the embodiment of the present application, the first current limiting resistor R2 can be called a "protection resistor", which is usually located at the port of the first current source U1 and plays the role of limiting the current size and dividing the voltage to protect the circuit safety.

[0096] In the embodiment of the present application, if the current provided by the first current source U1 is too large, it may cause overheating or even damage to components. In this case, by inserting a resistor of appropriate resistance (such as the first current-limiting resistor R2), the current can be reduced, protecting the components in the circuit. By effectively controlling the current, the stability and safety of the circuit can be ensured.

[0097] In some embodiments, see Figure 3The detection circuit 10 may further include a switching circuit, which includes a first switching element K1 and a second switching element K2. The first current source U1 and the first switching element K2 are connected to the first end of the interlock loop 20 to form a first current branch, and the first current source U1 and the second switching element K2 are connected to the second end of the interlock loop 20 to form a second current branch. That is, the first switching element K1 is connected between the first current source U1 and the first end of the interlock loop 20, and the second switching element K2 is connected between the first current source U1 and the second end of the interlock loop 20.

[0098] In the embodiment of the present application, both the first switching element K1 and the second switching element K2 can be a switch tube, a triode, a metal-oxide semiconductor field-effect transistor (MOSFET or MOS for short), an insulated gate bipolar transistor (IGBT), etc., and can even be other electrical controllers such as relays, without any limitation here. Figure 3 In the figure, the first switch element K1 and the second switch element K2 are schematically illustrated by taking MOS transistors as an example.

[0099] In the embodiment of the present application, the first switch element K1 is located on the first current branch, and the second switch element K2 is located on the second current branch. By controlling the on and off of the first and second switch elements K1 and K2, the direction of current injection can be controlled, enabling bidirectional sampling of both forward and reverse current injection. This not only resolves the issue of being unable to obtain the interlock connection status when a short-to-ground fault occurs, but also improves sampling accuracy, significantly reducing misdiagnosis caused by leakage current.

[0100] In some embodiments, the first switch element K1 and the second switch element K2 are not turned on at the same time. Accordingly, the detection circuit 10 is configured to, when the first switch element K1 is turned on and the second switch element K2 is turned off, inject a forward current into the interlock loop 20 based on the first current branch and obtain the collected first voltage through the first sampling terminal ADC1. Furthermore, the detection circuit 10 is configured to, when the first switch element K1 is turned off and the second switch element K2 is turned on, inject a reverse current into the interlock loop 20 based on the second current branch and obtain the collected second voltage through the second sampling terminal ADC2.

[0101] In the embodiment of the present application, the first switch element K1 and the second switch element K2 are not turned on at the same time, which means that the first current branch and the second current branch are not operating at the same time. In other words, the injection of forward current and the injection of reverse current do not occur at the same time. In this way, by controlling the on and off conditions of the first switch element K1 and the second switch element K2, the current injection direction can be changed to perform bidirectional sampling.

[0102] The first possible situation: Figure 4 As shown, at this time, the first switching element K1 is turned on and the second switching element K2 is turned off. In this case, the first current branch is operating and the second current branch is not operating. At this time, positive current injection and sampling are performed through the first current branch. At this time, the current value flowing through the load Rd of the interlocking loop is Ir=I-Ileak, which is significantly different from the expected current value I. Here, I represents the current value output by the first current source U1, and Ileak represents the leakage current generated when a short-to-ground fault occurs at the first end of the interlocking loop 20.

[0103] The second possible situation: Figure 5 As shown, at this time, the first switch element K1 is turned off and the second switch element K2 is turned on. In this case, the first current branch is inoperative, while the second current branch is operative. Reverse current injection and sampling are now performed through the second current branch. The interlocking loop's load Rd is now connected in series with the fourth resistor R4, which causes the leakage current. Therefore, the current flowing through load Rd is approximately Ileak. However, since the direction is opposite to that of the first current injection, Ir' = -Ileak. Subtracting the two currents yields the leakage-compensated value, Ir'' = Ir - Ir' = I – Ileak – (-Ileak) = I.

[0104] In this way, through the two samplings of forward current injection and reverse current injection, the leakage current generated by the short-to-ground fault can be compensated, so that a more accurate sampling value can be obtained, thereby significantly reducing the system's misjudgment rate of the fault.

[0105] That is to say, in the embodiment of the present application, due to the presence of the first switching element K1 and the second switching element K2, and the first switching element K1 is located on the first current branch and the second switching element K2 is located on the second current branch, it is possible to achieve the first current branch and the second current branch working at different times; in this way, by controlling the closing status of the first switching element K1 and the second switching element K2 to change the current injection direction, it is possible to achieve bidirectional sampling of forward current injection and reverse current injection, which not only solves the problem that normal sampling cannot be performed to determine the current interlocking connection state when a short-to-ground fault occurs, but also can realize leakage current compensation through two samplings, solves the accuracy deviation caused by the leakage current, thereby improving the sampling accuracy and greatly reducing the misjudgment rate caused by the influence of leakage current.

[0106] In another possible implementation, Figure 2 The detection circuit 10 is shown based on Figure 6 , the current source circuit 101 may include a first current source U1 and a second current source U2, wherein:

[0107] The first current source U1 is connected to the first end of the interlock loop 20 to form a first current branch;

[0108] The second current source U2 is connected to the second end of the interlock loop 20 to form a second current branch.

[0109] In the embodiment of the present application, two current sources can be used to implement the functions of forward current injection and reverse current injection. For example, forward current injection is implemented through the first current source U1, and reverse current injection is implemented through the second current source U2. In this way, by switching the current source to change the current injection direction, bidirectional sampling of forward and reverse current injection can also be achieved. Moreover, compared with the single current source in the related art, the use of two current sources here can continue sampling when a single current source fails, so as to detect whether there is an abnormality in the interlocking loop, thereby improving system stability.

[0110] In some embodiments, see Figure 6 The current source circuit 101 may further include a first current limiting resistor R2 and a second current limiting resistor R3, wherein the first current limiting resistor R2 is connected to the output end of the first current source U1, and the second current limiting resistor R3 is connected to the output end of the second current source U2.

[0111] In the embodiment of the present application, the first current limiting resistor R2 or the second current limiting resistor R3 can be called a "protection resistor", which is usually located at the port of the current source (such as the first current source U1 and the second current source U2), and plays the role of limiting the current size and voltage division to protect the circuit safety.

[0112] In the embodiment of the present application, taking the first current-limiting resistor R2 as an example, if the current value provided by the first current source U1 is too large, it may cause overheating or even damage to components. In this case, by inserting a resistor with an appropriate resistance value (such as the first current-limiting resistor R2), the current can be reduced, protecting the components in the circuit. By effectively controlling the current, the stability and safety of the circuit can be ensured.

[0113] It should also be noted that the value range of both the first current limiting resistor R2 and the second current limiting resistor R3 should be selected based on the specific application scenario and circuit requirements (such as the current, voltage, power requirements in the circuit and the heat dissipation performance of the resistor, etc.), and no limitation is imposed here.

[0114] In one possible implementation, see Figure 6 The first current source U1 may include a first enable terminal EN1 for receiving a first enable signal; the second current source U2 may include a second enable terminal EN2 for receiving a second enable signal.

[0115] In an embodiment of the present application, the detection circuit 10 is configured to, when the first enable signal is in a first level state and the second enable signal is in a second level state, inject a forward current into the interlock loop 20 based on the first current branch, and obtain the collected first voltage through the first sampling terminal ADC1; and the detection circuit 10 is also configured to, when the first enable signal is in a second level state and the second enable signal is in a first level state, inject a reverse current into the interlock loop 20 based on the second current branch, and obtain the collected second voltage through the second sampling terminal ADC2.

[0116] In the embodiment of the present application, the first enable signal is used to indicate whether the first current source U1 is enabled, that is, whether the first current source U1 is working. When the first enable signal is at a first level, it indicates that the first current source U1 is in an enabled state. At this time, the first current source U1 is working, and accordingly, the first current branch is working. At this time, the first current source U1 can inject a forward current into the interlocking loop 20 via the first current branch. When the first enable signal is at a second level, it indicates that the first current source U1 is in a disabled state. At this time, the first current source U1 is not working, and accordingly, the first current branch is not working. At this time, the first current source U1 cannot inject a forward current into the interlocking loop 20 via the first current branch.

[0117] In the embodiment of the present application, the second enable signal is used to indicate whether the second current source U2 is enabled, that is, whether the second current source U2 is working. When the second enable signal is in a first level state, it indicates that the second current source U2 is in an enabled state. At this time, the second current source U2 is working, and accordingly, the second current branch is working. At this time, the second current source U2 can inject a reverse current into the interlocking loop 20 via the second current branch; when the second enable signal is in a second level state, it indicates that the second current source U2 is in a disabled state. At this time, the second current source U2 is not working, and accordingly, the second current branch is not working. At this time, the second current source U2 cannot inject a reverse current into the interlocking loop 20 via the second current branch.

[0118] It should be noted that the first level state can be a high level and the second level state can be a low level; or the first level state can be a low level and the second level state can be a high level. The high level can be represented by "logic 1" and the low level can be represented by "logic 0".

[0119] For example, taking the first level state as a high level and the second level state as a low level as an example, if the first enable signal is at a high level and the second enable signal is at a low level, the first current source U1 is working at this time, then based on the first current branch, a forward current can be injected into the interlocking loop 20 to obtain the collected first voltage; if the first enable signal is at a low level and the second enable signal is at a high level, the second current source U2 is working at this time, then based on the second current branch, a reverse current can be injected into the interlocking loop 20 to obtain the collected second voltage.

[0120] That is to say, in the embodiment of the present application, since the first current source U1 is located on the first current branch and the second current source U2 is located on the second current branch, the two current sources can also be used to achieve the first current branch and the second current branch working at different times; in this way, by controlling the enabling status of the two current sources to change the current injection direction, bidirectional sampling of forward current injection and reverse current injection can be achieved, which not only solves the problem that normal sampling cannot be performed to determine the current interlocking connection status when a short-to-ground fault occurs, but also solves the accuracy deviation caused by the leakage current, thereby improving the sampling accuracy; using two current sources at the same time can also improve system stability.

[0121] In another possible implementation, Figure 6 The detection circuit 10 is shown based on Figure 7The detection circuit 10 may further include a switching circuit including a third switching element K3 and a fourth switching element K4. The first current source U1, the third switching element K3, and the first end of the interlock loop 20 are connected to form a first current branch, and the second current source U2, the fourth switching element K4 and the second end of the interlock loop 20 are connected to form a second current branch. That is, the third switching element K3 is connected between the first current source U1 and the first end of the interlock loop 20, and the fourth switching element K4 is connected between the second current source U2 and the second end of the interlock loop 20.

[0122] In the embodiment of the present application, both the third switching element K3 and the fourth switching element K4 can be a switch tube, a triode, a MOS tube, an IGBT, etc., or even other electrical controllers such as a relay, and no limitation is made here. Figure 7 In the figure, the third switch element K3 and the fourth switch element K4 are schematically illustrated by taking MOS tubes as an example.

[0123] In the embodiment of the present application, the third switch element K3 is located in the first current branch, and the fourth switch element K4 is located in the second current branch, thereby enabling the first and second current branches to operate independently of each other. By controlling the on / off states of the third and fourth switch elements K3 and K4, the current injection direction can be controlled, enabling bidirectional sampling of both forward and reverse current injection. This not only resolves the issue of being unable to obtain the interlock connection status during a short-to-ground fault, but also improves sampling accuracy. The simultaneous use of two current sources also enhances system stability.

[0124] In some embodiments, the third switch element K3 and the fourth switch element K4 are not turned on at the same time. Accordingly, the detection circuit 10 is configured to, when the third switch element K3 is turned on and the fourth switch element K4 is turned off, inject a forward current into the interlock loop 20 based on the first current branch and obtain the collected first voltage through the first sampling terminal ADC1. Furthermore, the detection circuit 10 is configured to, when the third switch element K3 is turned off and the fourth switch element K4 is turned on, inject a reverse current into the interlock loop 20 based on the second current branch and obtain the collected second voltage through the second sampling terminal ADC2.

[0125] In the embodiment of the present application, the third switch element K3 and the fourth switch element K4 are not turned on at the same time, which means that the first current branch and the second current branch are not operating at the same time. In other words, the injection of forward current and the injection of reverse current do not occur at the same time. In this way, by controlling the on and off conditions of the third switch element K3 and the fourth switch element K4, the current injection direction can be changed to perform bidirectional sampling.

[0126] The first possible situation: Figure 8As shown, at this time, the third switch element K3 is turned on and the fourth switch element K4 is turned off. In this case, the first current branch is operating and the second current branch is not operating. At this time, the first current source U1 injects and samples forward current through the first current branch. At this time, the current value flowing through the load Rd of the interlocking loop is Ir=I-Ileak, which is significantly different from the expected current value I. Here, I represents the current value output by the first current source U1, and Ileak represents the leakage current generated when a short-to-ground fault occurs at the first end of the interlocking loop 20.

[0127] The second possible situation: Figure 9 As shown, at this time, the third switch element K3 is turned off and the fourth switch element K4 is turned on. In this case, the first current branch is inoperative, while the second current branch is operative. At this time, the second current source U2 performs reverse current injection and sampling via the second current branch. At this time, the load Rd of the interlocking loop is connected in series with the fourth resistor R4, which causes the leakage current. Therefore, the current flowing through the load Rd is approximately Ileak. However, since the direction is opposite to that of the first current injection, Ir' = - Ileak. Subtracting the two now yields the value after leakage current compensation, Ir'' = Ir - Ir' = I – Ileak – (- Ileak) = I.

[0128] In this way, the leakage current generated by the short-to-ground fault can be compensated by two current sources and two samplings of positive and negative current injection, so that a more accurate sampling value can be obtained, thereby significantly reducing the system's misjudgment rate of faults.

[0129] That is to say, in the embodiment of the present application, due to the presence of the third switching element K3 and the fourth switching element K4, and the first current source U1 and the third switching element K3 are located on the first current branch, and the second current source U2 and the fourth switching element K4 are located on the second current branch, it is possible to achieve the first current branch and the second current branch working at different times; in this way, the working states of the two current sources are switched by controlling the closing state of the third switching element K3 and the fourth switching element K4, and the current injection direction is changed by switching the working state of the current source, which not only solves the problem that normal sampling cannot be performed to determine the current interlocking connection state when a short-to-ground fault occurs, but also realizes compensation for leakage current through two samplings, solves the accuracy deviation caused by leakage current, thereby improving the accuracy of sampling and greatly reducing the misjudgment rate caused by the influence of leakage current; at the same time, it can continue to sample when a single current source fails, thereby improving system stability.

[0130] It can also be understood that in an embodiment of the present application, the processing circuit 102 may include a sampling unit, which includes two sampling terminals (for example, a first sampling terminal ADC1 and a second sampling terminal ADC2), the first sampling terminal ADC1 is used to obtain a first voltage collected under the first current branch, and the second sampling terminal ADC2 is used to obtain a second voltage collected under the second current branch.

[0131] In the embodiment of the present application, the sampling unit may be integrated into a separate sampling chip, such as an analog to digital converter (ADC) chip; or the sampling unit may be provided in a microprocessor, which is not limited here.

[0132] It can also be understood that in the embodiment of the present application, the processing circuit 102 may further include a control unit configured to send a switching signal to a switching element in the detection circuit 10 or send an enable signal to a current source in the detection circuit 10 .

[0133] In the embodiment of this application, Figure 3 For example, at this time, the control unit can send switching signals to the first switching element K1 and the second switching element K2 respectively to control the on and off states of the first switching element K1 and the second switching element K2, thereby realizing bidirectional sampling of forward and reverse current injection.

[0134] In the embodiment of this application, Figure 6 For example, at this time, the control unit can send enable signals to the first current source U1 and the second current source U2 respectively to control the working states of the first current source U1 and the second current source U2, thereby realizing bidirectional sampling of positive and negative current injection.

[0135] In the embodiment of this application, Figure 7 For example, at this time, the control unit can send switching signals to the third switching element K3 and the fourth switching element K4 respectively to control the on and off states of the third switching element K3 and the fourth switching element K4, thereby realizing bidirectional sampling of forward and reverse current injection.

[0136] An embodiment of the present application provides a detection circuit, which is connected to an interlocking loop. By adding a reverse current injection loop in the detection circuit, bidirectional sampling detection of forward current injection and reverse current injection can be achieved, and the resistance of the interlocking loop is determined based on the voltage difference between the collected first voltage and the second voltage and the current value output by the current source circuit. In this way, not only can the problem of being unable to obtain the interlocking connection status when a short-to-ground fault occurs be solved, but the accuracy of sampling can also be improved, and the misdiagnosis caused by the influence of leakage current can be greatly reduced; after determining the resistance of the interlocking loop based on the bidirectional sampling detection, it is also possible to judge the current state of the interlock in the loop, such as whether the current interlocking connection is reliable or whether the current interlock is loose or has poor contact, thereby improving the reliability of the interlocking loop.

[0137] In another embodiment of the present application, Figure 10 This is a flow chart of a detection method provided in an embodiment of the present application. Figure 10 As shown, the detection method may include:

[0138] S1001: Acquire a first voltage collected when a first current branch is operating and a second voltage collected when a second current branch is operating.

[0139] In an embodiment of the present application, the detection method is applied to the detection circuit 10 described in the aforementioned embodiment, and the detection circuit 10 is connected to an interlock loop. A current source circuit is connected to a first end of the interlock loop to form a first current branch, and a current source circuit is connected to a second end of the interlock loop to form a second current branch. Furthermore, the first current branch and the second current branch do not operate simultaneously.

[0140] In some embodiments, the current source circuit may include a first current source, and the detection circuit may further include a first switching element and a second switching element. Accordingly, obtaining a first voltage collected when the first current branch is operating and a second voltage collected when the second current branch is operating may include:

[0141] When the first switch element is turned on and the second switch element is turned off, a forward current is injected into the interlock loop based on the first current branch, and a first voltage is acquired through the first sampling terminal; and

[0142] When the first switch element is turned off and the second switch element is turned on, a reverse current is injected into the interlock loop based on the second current branch, and the collected second voltage is obtained through the second sampling terminal.

[0143] In the embodiment of the present application, the first switching element and the second switching element are not turned on at the same time. The first switching element is located in the first current branch, and the second switching element is located in the second current branch. By controlling the on and off of the first and second switching elements, the current injection direction can be controlled, enabling bidirectional sampling of both forward and reverse current injection.

[0144] That is, in the embodiment of the present application, due to the presence of the first switching element and the second switching element, the first current branch and the second current branch can operate at different times. By controlling the on / off status of the first switching element and the second switching element to change the current injection direction, bidirectional sampling of forward and reverse current injection can be achieved. This not only solves the problem of being unable to perform normal sampling to determine the current interlock connection state when a short-to-ground fault occurs, but also compensates for leakage current through two samplings, solving the accuracy deviation caused by leakage current, thereby improving sampling accuracy and significantly reducing the misjudgment rate caused by leakage current.

[0145] In some embodiments, the current source circuit may include a first current source and a second current source, wherein the first current source includes a first enable terminal and the second current source includes a second enable terminal. Accordingly, obtaining a first voltage sampled when the first current branch is operating and a second voltage sampled when the second current branch is operating may include:

[0146] When the first enable signal received by the first enable terminal is in a first level state and the second enable signal received by the second enable terminal is in a second level state, injecting a forward current into the interlock loop based on the first current branch, and acquiring the collected first voltage through the first sampling terminal; and

[0147] When the first enable signal received by the first enable terminal is in the second level state and the second enable signal received by the second enable terminal is in the first level state, a reverse current is injected into the interlock loop based on the second current branch, and the collected second voltage is obtained through the second sampling terminal.

[0148] In an embodiment of the present application, the first enable terminal is used to receive a first enable signal, and the first enable signal can be used to indicate whether the first current source is enabled, that is, whether the first current source is working. When the first enable signal is in a first level state, it indicates that the first current source is in an enabled state. At this time, the first current source is working, and accordingly, the first current branch is working, so the first current source can inject a forward current into the interlocking loop via the first current branch; when the first enable signal is in a second level state, it indicates that the first current source is in a disabled state. At this time, the first current source is not working, and accordingly, the first current branch is not working, so the first current source cannot inject a forward current into the interlocking loop via the first current branch.

[0149] In an embodiment of the present application, the second enable terminal is used to receive a second enable signal, and the second enable signal can be used to indicate whether the second current source is enabled, that is, whether the second current source is working. When the second enable signal is at a first level, it indicates that the second current source is in an enabled state. At this time, the second current source is working, and accordingly, the second current branch is working, so the second current source can inject a reverse current into the interlock loop via the second current branch. When the second enable signal is at a second level, it indicates that the second current source is in a disabled state. At this time, the second current source is not working, and accordingly, the second current branch is not working, so the second current source cannot inject a reverse current into the interlock loop via the second current branch.

[0150] It should be noted that the first level state can be a high level and the second level state can be a low level; or the first level state can be a low level and the second level state can be a high level. The high level can be represented by "logic 1" and the low level can be represented by "logic 0".

[0151] That is to say, in the embodiment of the present application, since the first current source is located on the first current branch and the second current source is located on the second current branch, the two current sources can also be used to achieve the first current branch and the second current branch working at different times; in this way, by controlling the enabling status of the two current sources to change the current injection direction, bidirectional sampling of forward current injection and reverse current injection can be achieved, which not only solves the problem that normal sampling cannot be performed to determine the current interlocking connection status when a short-to-ground fault occurs, but also solves the accuracy deviation caused by the leakage current, thereby improving the sampling accuracy; using two current sources at the same time can also improve system stability.

[0152] In some embodiments, the current source circuit includes a first current source and a second current source, and the detection circuit further includes a third switch element and a fourth switch element. Accordingly, obtaining a first voltage collected when the first current branch is operating and a second voltage collected when the second current branch is operating may include:

[0153] When the third switch element is turned on and the fourth switch element is turned off, a forward current is injected into the interlock loop based on the first current branch, and a first voltage is acquired through the first sampling terminal; and

[0154] When the third switch element is turned off and the fourth switch element is turned on, a reverse current is injected into the interlock loop based on the second current branch, and the collected second voltage is obtained through the second sampling terminal.

[0155] In the embodiment of the present application, the third switching element and the fourth switching element are not turned on at the same time. The third switching element is located in the first current branch, and the fourth switching element is located in the second current branch, thereby enabling the first current branch and the second current branch to operate at different times. By controlling the on and off of the third and fourth switching elements, the current injection direction can also be controlled, enabling bidirectional sampling of both forward and reverse current injection.

[0156] That is to say, in the embodiment of the present application, due to the presence of the third switching element and the fourth switching element, and the first current source and the third switching element are located on the first current branch, and the second current source and the fourth switching element are located on the second current branch, it is also possible to achieve the first current branch and the second current branch working at different times; in this way, the working states of the two current sources are switched by controlling the closing state of the third switching element and the fourth switching element, and the current injection direction is changed by switching the working state of the current source, which not only solves the problem that normal sampling cannot be performed to determine the current interlocking connection state when a short-to-ground fault occurs, but also can realize leakage current compensation through two samplings, solves the accuracy deviation caused by the leakage current, thereby improving the sampling accuracy and greatly reducing the misjudgment rate caused by the influence of leakage current; at the same time, it can continue to sample when a single current source fails, thereby improving system stability.

[0157] S1002 , determining a voltage difference between the first voltage and the second voltage.

[0158] S1003, determining the resistance of the interlocking loop according to the voltage difference and the current value output by the current source circuit; wherein the resistance of the interlocking loop is used to determine whether there is an abnormality in the interlocking loop.

[0159] In an embodiment of the present application, the first current branch and the second current branch have opposite current directions when flowing through the interlock loop. Thus, after obtaining the first and second voltages sampled twice, the voltage values ​​across the load of the interlock loop can be obtained, thereby calculating the voltage difference between the first and second voltages (i.e., the voltage drop generated by the load). Then, based on the voltage difference and the current value output by the current source circuit, the resistance of the interlock loop can be calculated using the resistance formula R = U / I. The resistance of the interlock loop can be used to determine whether there is an anomaly in the interlock loop.

[0160] In some embodiments, after determining the resistance of the interlock circuit, the detection method may further include:

[0161] When the resistance value of the interlock circuit is within a preset range, it is determined that there is no abnormality in the interlock circuit;

[0162] When the resistance value of the interlocking circuit is greater than an upper limit value of a preset range, it is determined that an abnormality exists in the interlocking circuit.

[0163] In the embodiment of the present application, the preset range can be set to [0, Δ], where 0 represents the lower limit of the preset range and Δ represents the upper limit of the preset range. For example, the value of Δ can be 1, 2, 3, etc., which is not limited here.

[0164] That is, in the embodiment of the present application, if the resistance of the interlocking circuit is within the preset range, that is, the resistance of the interlocking circuit is 0 ohms or a few ohms, then it can be determined that there is no abnormality in the interlocking circuit, that is, the connection of the interlocking circuit is reliable. If the resistance of the interlocking circuit is greater than the upper limit of the preset range, that is, the resistance of the interlocking circuit is large, then it can be determined that there is an abnormality in the interlocking circuit, that is, the connection of the interlocking circuit is unreliable, for example, the current interlock is loose or has poor contact.

[0165] The embodiment of the present application provides a detection method, which uses the detection circuit in the aforementioned embodiment to obtain a first voltage collected when the first current branch is working and a second voltage collected when the second current branch is working; then determines the voltage difference between the first voltage and the second voltage; and then determines the resistance of the interlocking loop based on the voltage difference and the current value output by the current source circuit; wherein the resistance of the interlocking loop is used to determine whether there is an abnormality in the interlocking loop. In this way, the bidirectional sampling detection based on forward current injection and reverse current injection can not only solve the problem of being unable to obtain the interlocking connection status when a short-to-ground fault occurs, but also improve the accuracy of sampling, and greatly reduce the misdiagnosis caused by the influence of leakage current; in addition, after determining the resistance of the interlocking loop based on the bidirectional sampling detection, it is also possible to determine the current state of the interlock in the loop, such as whether the current interlocking connection is reliable or whether the current interlock is loose or has poor contact, thereby improving the reliability of the interlocking loop.

[0166] In another embodiment of the present application, Figure 11 This is a schematic diagram of the structure of a detection system provided in an embodiment of the present application. Figure 11 As shown, the detection system 110 may include an interlocking loop 20 and a circuit board 1101 , wherein the circuit board 1101 includes the detection circuit 10 as described in any one of the aforementioned embodiments, and the detection circuit 10 is connected to the interlocking loop 20 .

[0167] In an embodiment of the present application, the circuit board 1101 here can be a BMU single board, which includes a detection circuit 10. In this way, since the detection system includes a detection circuit, the detection circuit is connected to the interlocking loop. By adding a reverse current injection loop in the detection circuit, bidirectional sampling detection of forward current injection and reverse current injection can be achieved. This not only improves the stability of the system and solves the problem of being unable to obtain the interlocking connection status when a short-to-ground fault occurs, but also improves the accuracy of sampling and greatly reduces the misdiagnosis caused by the influence of leakage current; at the same time, according to the determined resistance value of the interlocking loop, it is also possible to accurately judge the current state of the interlock in the loop, such as whether the current interlocking connection is reliable or the current interlock is loose or has poor contact, thereby improving the reliability of the interlocking loop.

[0168] In a specific embodiment, Figure 12 This is a schematic diagram of an application scenario of a detection system provided in an embodiment of the present application. Figure 12 As shown, the detection system 110 may include a BMU board 1201 and an interlock circuit 20. The BMU board 1201 may include a first current source U1, a microprocessor U3, a first switch element K1, a second switch element K2, a grounding resistor R1, and a current limiting resistor R2.

[0169] In the embodiments of this application, Figure 12 As shown, a current can be injected in a forward direction and a current can be injected in a reverse direction, and then the voltage values ​​obtained by the two samples can be subtracted to calculate the resistance value of the high-voltage interlock.

[0170] In the embodiment of the present application, a new high-voltage interlock detection solution is provided, which is described in detail as follows:

[0171] (1) The first current source U1 will stably output a rated current value;

[0172] (2) The microprocessor U3 obtains the voltage value across the load to obtain the voltage difference (i.e., the voltage drop generated by the load);

[0173] (3) The resistance value of the high-voltage interlock can be calculated from the voltage difference and the current value output by the first current source, and the current state of the high-voltage interlock can be judged according to a pre-agreed preset range, that is, whether there is an abnormality in the interlock circuit;

[0174] (4) When a short-to-ground fault occurs or in order to reduce the impact of leakage current on sampling accuracy, the reverse current injection sampling detection can be enabled, and the difference between the two sampling values ​​can be calculated to obtain the compensated resistance value.

[0175] It should be noted that if only one sampling channel is used, it will not be possible to properly sample and determine the current state of the high-voltage interlock when a short-to-ground fault occurs. Furthermore, using only one sampling channel will result in accuracy deviations due to leakage current, which may cause the system to make incorrect diagnoses after receiving the sampled value. Based on this, the present embodiment adds sampling detection for reverse current injection.

[0176] In one possible implementation, Figure 12 As shown, the current injection direction can be changed by controlling the closing conditions of the two switching elements to perform bidirectional sampling. The details are as follows:

[0177] During the first sampling, the first switch element K1 can be closed and the second switch element K2 can be opened to perform forward current injection and sampling. At this time, the current value flowing through the load Rd is Ir = I-Ileak, which is significantly different from the expected I.

[0178] During the second sampling, the second switch K2 can be closed and the first switch K1 opened for reverse current injection and sampling. At this point, the load Rd is connected in series with the fourth resistor R4, which causes the leakage current. The current flowing through the load Rd is approximately Ileak, but because it is in the opposite direction from the first current injection, Ir' = - Ileak. Subtracting the two currents yields the leakage-compensated value Ir'' = Ir - Ir' = I – Ileak – (- Ileak) = I.

[0179] This can obtain more accurate sampling values, which can significantly reduce the system's misjudgment rate of faults.

[0180] In another possible implementation, two current sources (e.g., a first current source U1 and a second current source U2) can be used to implement bidirectional current injection. This implementation enhances stability and can continue to provide sampled data to the sampling terminal of the processing circuit or the ADC chip even if one current source fails or its output is unstable.

[0181] In the embodiments of the present application, the specific implementation of the aforementioned embodiments is described in detail through the above embodiments. It can be seen that according to the technical solution of the aforementioned embodiments, a reverse detection injection loop can be added to the detection circuit, and the current injection direction can be controlled by the closed state of the switch element to achieve forward and reverse detection. This can avoid the inability to obtain the interlock connection state due to a short circuit in the high-voltage interlock circuit, and can greatly reduce the misdiagnosis caused by leakage current at the PIN port. In addition, the current injection direction can be switched by switching the current source, which can also improve the stability of the system. When a single current source fails, it can still provide sampling data to the sampling end of the processing circuit or the ADC chip, thereby improving the reliability of the high-voltage interlock circuit.

[0182] In another embodiment of the present application, the detection system can be applied to a BMS. Figure 13 This is a schematic diagram of the structure of a battery management system provided in an embodiment of the present application. Figure 13 As shown, the battery management system 130 may include an interlocking loop 20 and a circuit board 1101 , wherein the circuit board 1101 may include a detection circuit 10 as described in any one of the aforementioned embodiments, and the detection circuit 10 is connected to the interlocking loop 20 .

[0183] In another embodiment of the present application, Figure 14 This is a schematic diagram of the structure of a battery pack provided in an embodiment of the present application. Figure 14 As shown, the battery pack 140 may include a battery 1401 and a battery management system 130 as described in the aforementioned embodiment. The battery management system 130 can perform various management and monitoring operations on the battery 1401, such as data acquisition and monitoring, balancing management, protection functions and fault diagnosis, charging management, thermal management, etc., to achieve safe monitoring and effective management of the battery 1401.

[0184] In another embodiment of the present application, the embodiment of the present application further provides an electric drive device, which may include the detection system 120 as described in the aforementioned embodiment; or, the electric drive device may include the battery management system 130 as described in the aforementioned embodiment; or, the electric drive device may include the battery pack 140 as described in the aforementioned embodiment.

[0185] In the embodiments of the present application, the electric drive device is a technical device that converts electrical energy into mechanical energy and is used to drive various mechanical devices to operate. Here, the electric drive device may include a battery pack, which can control the power output of the battery pack to power a load.

[0186] For example, the electric drive device may be a new energy vehicle (e.g., an electric vehicle), a ship, an electric motorcycle, an airplane, etc., and the load may be an electrical device within the electric drive device. For example, if the electric drive device 100 is an electric vehicle, the load may be a motor within the electric vehicle, etc., without limitation.

[0187] It should be noted that the embodiments of the present application may be provided as hardware circuits, methods, systems, or computer program products. Therefore, the present application may take the form of hardware embodiments, software embodiments, or embodiments combining software and hardware. Furthermore, the present application may take the form of a computer program product implemented on one or more computer-readable storage media (including but not limited to magnetic disk storage and optical storage) containing computer-usable program code.

[0188] The present application is described with reference to flowcharts and / or block diagrams of hardware circuits, methods, devices (systems), and computer program products according to embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0189] It should also be noted that, in this application, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or apparatus comprising the element.

[0190] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0191] The methods disclosed in the several method embodiments provided in this application can be arbitrarily combined without conflict to obtain new method embodiments.

[0192] The features disclosed in the several product embodiments provided in this application can be arbitrarily combined without conflict to obtain new product embodiments.

[0193] The features disclosed in the several method or device embodiments provided in this application can be arbitrarily combined without conflict to obtain new method embodiments or device embodiments.

[0194] The above is only a specific implementation method of the present application, but the scope of protection of the present application is not limited thereto. Any technician familiar with this technical field can easily think of changes or replacements within the technical scope disclosed in this application, which should be covered by the scope of protection of the present application.

Claims

1. A detection circuit connected to an interlocking circuit, characterized in that: The detection circuit includes a current source circuit and a processing circuit, wherein the current source circuit is connected to the first end of the interlock loop to form a first current branch, and the current source circuit is also connected to the second end of the interlock loop to form a second current branch; wherein: The processing circuit includes a first sampling terminal and a second sampling terminal, the first sampling terminal is connected to the first terminal of the interlock loop, and the second sampling terminal is connected to the second terminal of the interlock loop; The processing circuit is configured to, when a short-to-ground fault occurs at the first end of the interlocking loop or a leakage current exists at the first end of the interlocking loop, obtain, through the first sampling end, a first voltage collected when the first current branch is operating, and obtain, through the second sampling end, a second voltage collected when the second current branch is operating, and determine the resistance of the interlocking loop based on a voltage difference between the first voltage and the second voltage and a current value output by the current source circuit; wherein the resistance of the interlocking loop is used to determine whether the interlocking loop has an abnormality; wherein: When the current source circuit includes a first current source, the detection circuit further includes a switching circuit, the switching circuit including a first switching element and a second switching element, the first switching element and the second switching element being turned on at different times; and the first current source, the first switching element, and the first end of the interlock loop are connected to form the first current branch, and the first current source, the second switching element, and the second end of the interlock loop are connected to form the second current branch; or, When the current source circuit includes a first current source and a second current source, the first current source is connected to the first end of the interlocking loop to form the first current branch, the second current source is connected to the second end of the interlocking loop to form the second current branch, and the first current source and the second current source do not work at the same time.

2. The detection circuit according to claim 1, characterized in that In the case where the current source circuit comprises a first current source, The detection circuit is configured to inject a forward current into the interlock loop based on the first current branch when the first switching element is turned on and the second switching element is turned off, and obtain the collected first voltage through the first sampling terminal; as well as The detection circuit is further configured to inject a reverse current into the interlock loop based on the second current branch when the first switch element is turned off and the second switch element is turned on, and obtain the collected second voltage through the second sampling terminal.

3. The detection circuit according to claim 1, characterized in that: In the case where the current source circuit includes a first current source and a second current source, the first current source includes a first enable terminal, the first enable terminal is used to receive a first enable signal; the second current source includes a second enable terminal, the second enable terminal is used to receive a second enable signal; The detection circuit is configured to, when the first enable signal is in a first level state and the second enable signal is in a second level state, inject a forward current into the interlock loop based on the first current branch and obtain the collected first voltage through the first sampling terminal; as well as The detection circuit is further configured to inject a reverse current into the interlock loop based on the second current branch when the first enable signal is in the second level state and the second enable signal is in the first level state, and obtain the collected second voltage through the second sampling terminal.

4. The detection circuit according to claim 1, characterized in that: In the case where the current source circuit includes a first current source and a second current source, the detection circuit further includes a switch circuit, wherein: The switching circuit includes a third switching element and a fourth switching element, and the first current source, the third switching element and the first end of the interlocking loop are connected to form the first current branch, and the second current source, the fourth switching element and the second end of the interlocking loop are connected to form the second current branch.

5. The detection circuit according to claim 4, characterized in that: The detection circuit is configured to, when the third switch element is turned on and the fourth switch element is turned off, inject a forward current into the interlock loop based on the first current branch, and obtain the collected first voltage through the first sampling terminal; as well as The detection circuit is further configured to inject a reverse current into the interlock loop based on the second current branch when the third switch element is turned off and the fourth switch element is turned on, and obtain the collected second voltage through the second sampling terminal.

6. The detection circuit according to any one of claims 1 to 5, characterized in that: The detection circuit further includes a grounding resistor, a first end of the grounding resistor is connected to the second end of the interlocking loop, and a second end of the grounding resistor is connected to the ground.

7. A detection method, characterized in that: The detection circuit according to any one of claims 1 to 6 is connected to an interlocking circuit; the detection method comprises: Acquire a first voltage acquired when the first current branch is operating and a second voltage acquired when the second current branch is operating; determining a voltage difference between the first voltage and the second voltage; The resistance of the interlocking loop is determined according to the voltage difference and the current value output by the current source circuit; wherein the resistance of the interlocking loop is used to determine whether there is an abnormality in the interlocking loop.

8. The detection method according to claim 7, characterized in that The current source circuit includes a first current source, and the detection circuit further includes a first switching element and a second switching element; The acquiring of the first voltage collected when the first current branch is operating and the second voltage collected when the second current branch is operating includes: When the first switch element is turned on and the second switch element is turned off, injecting a forward current into the interlock loop based on the first current branch, and acquiring a collected first voltage through the first sampling terminal; as well as When the first switch element is turned off and the second switch element is turned on, a reverse current is injected into the interlock loop based on the second current branch, and the collected second voltage is obtained through the second sampling terminal.

9. The detection method according to claim 7, characterized in that The current source circuit includes a first current source and a second current source, wherein the first current source includes a first enable terminal and the second current source includes a second enable terminal; and obtaining a first voltage collected when the first current branch is operating and a second voltage collected when the second current branch is operating includes: When the first enable signal received by the first enable terminal is in a first level state and the second enable signal received by the second enable terminal is in a second level state, injecting a forward current into the interlock loop based on the first current branch, and acquiring the collected first voltage through the first sampling terminal; and When the first enable signal received by the first enable terminal is in the second level state and the second enable signal received by the second enable terminal is in the first level state, a reverse current is injected into the interlock loop based on the second current branch, and the collected second voltage is obtained through the second sampling terminal.

10. The detection method according to claim 7, characterized in that: The current source circuit includes a first current source and a second current source, and the detection circuit further includes a third switching element and a fourth switching element; The acquiring of a first voltage collected in the first current branch and a second voltage collected in the second current branch includes: When the third switch element is turned on and the fourth switch element is turned off, injecting a forward current into the interlock loop based on the first current branch, and acquiring the collected first voltage through the first sampling terminal; as well as When the third switch element is turned off and the fourth switch element is turned on, a reverse current is injected into the interlock loop based on the second current branch, and the collected second voltage is obtained through the second sampling terminal.

11. A battery management system, characterized in that: The battery management system includes an interlocking loop and a circuit board, wherein the circuit board includes the detection circuit according to any one of claims 1 to 6.

12. A battery pack, characterized in that: The battery pack includes batteries and the battery management system according to claim 11.

13. An electric drive device, characterized in that: The electric drive device includes the battery management system according to claim 11 or the battery pack according to claim 12.

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