Detection circuit, detection method, system, battery pack and electric driving equipment

Abstract

The invention discloses a detection circuit, a detection method, a detection system, a battery pack and electric driving equipment, and the detection circuit comprises a current source circuit which is connected with a first end of an interlocking loop to form a first current branch, and the current source circuit is also connected with a second end of the interlocking loop to form a second current branch; the processing circuit comprises a first sampling end and a second sampling end, and is configured to acquire a first voltage acquired when the first current branch works through the first sampling end and acquire a second voltage acquired when the second current branch works through the second sampling end; the resistance value of the interlocking loop is determined according to the voltage difference value between the first voltage and the second voltage and the current value output by the current source circuit; wherein the resistance value of the interlocking loop is used for judging whether the interlocking loop is abnormal or not. Therefore, the problem that the interlocking connection state cannot be obtained when the short earth fault occurs can be solved, misdiagnosis caused by the influence of the leakage current can be reduced, and the reliability of an interlocking loop is improved.

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] As new energy vehicles become more and more popular, the battery management system (BMS) and its operating stability have always been a topic of concern to users. If the running system cannot read or identify the high-voltage interlock status normally, it may cause immeasurable impact on users and even lead to serious safety accidents.

[0003] In order to solve the high-voltage safety problem, a common solution is to use voltage-type or current-type high-voltage interlocking, such as by detecting the voltage divider or the voltage drop on the resistor, or other detection methods for diagnosis. However, these solutions are still not ideal and cannot accurately obtain the interlocking connection status of the current high-voltage connector, and may even cause false alarms of high-voltage interlocking 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 implemented as follows: In a first aspect, an embodiment of the present application provides a detection circuit, 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 also connected to a second end of the interlocking 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 interlocking loop, and the second sampling terminal is connected to the second terminal of the interlocking loop; The processing circuit is configured to obtain a first voltage collected when the first current branch is working through a first sampling terminal, obtain a second voltage collected when the second current branch is working through a second sampling terminal, and determine the resistance value of the interlocking loop according to the voltage difference between the first voltage and the second voltage and the 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: When the current source circuit includes a first current source, the detection circuit further includes a switch circuit, the switch circuit includes a first switch element and a second switch element, and the first current source, the first switch element and a first end of the interlocking loop are connected to form a first current branch, and the first current source, the second switch element and a second end of the interlocking loop are connected to form a 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 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.

[0006] Through the above technical means, whether the current source circuit includes the first current source or the current source circuit includes the first current source and the second current source, the current direction of the first current branch and the second current branch when flowing through the interlocking loop is opposite. That is to say, a second current branch (for example, a reverse current injection loop) with a current direction opposite to that of the first current branch is added to the detection circuit, so that bidirectional sampling detection of forward current injection and reverse current injection can be realized, 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, according to the bidirectional sampling detection, not only can the problem of being unable to obtain the interlocking connection state when a short-to-ground fault occurs be solved, but also the sampling accuracy can be improved, and the misdiagnosis caused by the influence of leakage current can be greatly reduced; after determining the resistance value of the interlocking loop according to the bidirectional sampling detection, it is also possible to judge the current state of the interlocking in the loop, such as whether the current interlocking connection is reliable or the current interlocking has a loose or poor contact problem, thereby improving the reliability of the interlocking loop.

[0007] 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 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 switching element is turned off and the second switching element is turned on, and obtain the collected second voltage through the second sampling terminal.

[0008] Through the above-mentioned technical means, due to the existence of the first switch element and the second switch element, and the first switch element is located on the first current branch, and the second switch 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 state of the first switch element and the second switch 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 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.

[0009] 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.

[0010] 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 realize the first current branch and the second current branch working at different times; in this way, the current injection direction is changed by controlling the enabling status of the two current sources, so that bidirectional sampling of forward current injection and reverse current injection can be realized, which can not only solve the problem that normal sampling cannot be performed to determine the current interlocking connection state when a short-to-ground fault occurs, but also solve the accuracy deviation caused by the leakage current, thereby improving the sampling accuracy; using two current sources at the same time can also improve the stability of the system.

[0011] 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.

[0012] Through the above technical means, the third switch element is located on the first current branch, and the fourth switch element is located on the second current branch. In this way, by controlling the on and off of the third switch element and the fourth switch element, the current injection direction can also be controlled to achieve bidirectional sampling of forward current injection and reverse current injection, which can not only solve the problem of being unable to obtain the interlocking connection state when a short-to-ground fault occurs, but also improve the sampling accuracy; using two current sources at the same time can also improve system stability.

[0013] 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 switch element is turned on and the fourth switch element is turned off, 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 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.

[0014] Through the above-mentioned technical means, due to the existence of the third switch element and the fourth switch element, and the first current source and the third switch element are located on the first current branch, and the second current source and the fourth switch element are located on the second current branch, it is possible to achieve that the first current branch and the second current branch do not work at the same time; in this way, the working states of the two current sources are switched by controlling the closing state of the third switch element and the fourth switch 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 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 leakage current; at the same time, sampling can continue when a single current source fails, thereby improving system stability.

[0015] 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 interlocking loop, and a second end of the grounding resistor is connected to the ground.

[0016] 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.

[0017] 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 the interlocking loop; the detection method includes: 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 value of the interlocking loop is determined according to the voltage difference and the 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.

[0018] Through the above technical means, after obtaining the first voltage collected under the first current branch and the second voltage collected under the second current branch, the voltage difference between the first voltage and the second voltage is determined, and then the resistance of the interlocking loop is determined according to the voltage difference and the current value output by the current source circuit, and the resistance of the interlocking loop is used to determine whether there is an abnormality in the interlocking loop. In this way, since the current directions of the first current branch and the second current branch when flowing through the interlocking loop are opposite, at this time, the bidirectional sampling detection based on the positive and negative current injection (such as the first voltage and the second voltage obtained) can not only solve the problem that the interlocking connection state cannot be obtained when a short-to-ground fault occurs, but also improve the sampling accuracy, greatly reducing the misdiagnosis caused by the influence of leakage current; in addition, after determining the resistance of the interlocking loop according to the bidirectional sampling detection, it is also possible to judge the current state of the interlocking in the loop, such as whether the current interlocking connection is reliable or the current interlocking has a problem of looseness or poor contact, thereby improving the reliability of the interlocking loop.

[0019] In some embodiments, the current source circuit includes a first current source, and the detection circuit also includes a first switch element and a second switch element; acquiring a first voltage collected when the first current branch is working and a second voltage collected when the second current branch is working, includes: When the first switch element is turned on and the second switch element is turned off, a forward current is injected into the interlocking loop based on the first current branch, and the collected first voltage is acquired through the first sampling terminal; and 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.

[0020] Through the above technical means, due to the presence of the first switch element and the second switch element, the first current branch and the second current branch can work at different times. In this way, the current injection direction is changed by controlling the on-off status of the first switch element and the second switch element, so that bidirectional sampling of forward current injection and reverse current injection can be achieved, which can not only solve the problem that normal sampling cannot be performed to determine the current interlocking connection state when a short-to-ground fault occurs, but also realize leakage current compensation through two samplings, solve the accuracy deviation caused by the leakage current, and thus improve the accuracy of sampling, greatly reducing the misjudgment rate caused by the influence of leakage current.

[0021] In some embodiments, the current source circuit includes a first current source and a second current source, and 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 working and a second voltage collected when the second current branch is working, 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 at the first enable terminal is in the second level state and the second enable signal received at 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 acquired through the second sampling terminal.

[0022] 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 realize the first current branch and the second current branch working at different times; in this way, the current injection direction is changed by controlling the enabling status of the two current sources, so that bidirectional sampling of forward current injection and reverse current injection can be realized, which can not only solve the problem that normal sampling cannot be performed to determine the current interlocking connection state when a short-to-ground fault occurs, but also solve the accuracy deviation caused by the leakage current, thereby improving the sampling accuracy; using two current sources at the same time can also improve the stability of the system.

[0023] 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; acquiring a first voltage collected when the first current branch is working and a second voltage collected when the second current branch is working, comprises: 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 the collected first voltage is acquired through the first sampling terminal; and 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.

[0024] Through the above-mentioned technical means, due to the existence of the third switch element and the fourth switch element, and the first current source and the third switch element are located on the first current branch, and the second current source and the fourth switch 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 switch element and the fourth switch 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 realizes leakage current compensation through two samplings, solves the accuracy deviation caused by the leakage current, and thus improves the sampling accuracy, 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.

[0025] 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.

[0026] In a fourth aspect, an embodiment of the present application provides a battery pack, comprising a battery and a battery management system as described in the third aspect.

[0027] 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 by the fourth aspect.

[0028] It should be understood that the above general description and the following detailed description are merely exemplary and explanatory, and are not intended to limit the technical solutions of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A schematic diagram of the structure of a detection circuit provided in an embodiment of the present application Figure 1 ; Figure 2 A schematic diagram of the structure of a detection circuit provided in an embodiment of the present application Figure 2 ; Figure 3 A schematic diagram of the structure of a detection circuit provided in an embodiment of the present application Figure 3 ; Figure 4 A schematic diagram of the structure of a detection circuit provided in an embodiment of the present application Figure 4 ; Figure 5 A schematic diagram of the structure of a detection circuit provided in an embodiment of the present application Figure 5 ; Figure 6 A schematic diagram of the structure of a detection circuit provided in an embodiment of the present application Figure 6 ; Figure 7 A schematic diagram of the structure of a detection circuit provided in an embodiment of the present application Figure 7 ; Figure 8 A schematic diagram of the structure of a detection circuit provided in an embodiment of the present application Figure 8 ; Fig. 9 A schematic diagram of the structure of a detection circuit provided in an embodiment of the present application Figure 9 ; Fig.10 A schematic diagram of a detection method provided in an embodiment of the present application; Fig.11 A schematic diagram of the structure of a detection system provided in an embodiment of the present application; Fig.12 A schematic diagram of an application scenario of a detection system provided in an embodiment of the present application; Fig.13 A schematic diagram of the structure of a battery management system provided in an embodiment of the present application; Fig.14 A schematic diagram of the composition structure of a battery pack provided in an embodiment of the present application. DETAILED DESCRIPTION

[0030] 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 in conjunction with the accompanying drawings. The attached drawings are for reference only and are not used to limit the embodiments of the present application.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application.

[0032] In the following description, reference is made to “some embodiments”, which describe 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.

[0033] 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 in 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.

[0034] In addition, the reference to "embodiment" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0035] The following is an introduction to the relevant terms and technologies of this application.

[0036] 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 unit to ensure the safe use of the battery during the charging and discharging process.

[0037] Microprogrammed Control Unit (MCU), also known as "microcontroller" or "microprocessor" for short, is the core control part of BMS, responsible for signal detection and command control.

[0038] 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.

[0039] 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.

[0040] High Voltage Interlock Loop (HVIL), also known as "high voltage interlock", is a safety mechanism that mainly uses low voltage signals to check the integrity and continuity of the entire high voltage system circuit, identify abnormal disconnection of the circuit, and promptly disconnect the control electrical components at the high voltage input end. In simple terms, it is to check the on / off (danger) of the high voltage circuit through the on / off signal (safety) of the low voltage circuit.

[0041] 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 areas such as energy storage.

[0042] At present, new energy batteries are increasingly used in life and industry. New energy batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, but are also widely used in electric vehicles such as electric bicycles, electric motorcycles, electric cars, as well as aerospace and other fields. With the continuous expansion of the application field of power batteries, the market demand is also constantly expanding.

[0043] 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, so as to supply power to an electrical device. A battery cell may be a secondary battery, which refers to a battery cell that can be activated by charging the active material after the battery cell is discharged and can 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., which is not limited here.

[0044] 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 connection through a busbar component.

[0045] With the widespread application of batteries in the field of power batteries and energy storage, the replacement of fuel vehicles by new energy vehicles (such as electric vehicles) has become a development trend in the automotive industry. People are paying more and more attention to the safety issues of new energy vehicles. The biggest difference between new energy vehicles and traditional vehicles is that new energy vehicles rely on high voltage and high current to provide power for the vehicle, so high-voltage safety issues cannot be ignored in the design of new energy vehicles. The common safety monitoring system for high-voltage circuits is the high-voltage interlock circuit, which is mainly used to monitor the on-off status of various high-voltage components of the vehicle. According to the detection situation, the vehicle controller decides whether to disconnect the high-voltage circuit to keep the vehicle in a safe state.

[0046] In an era when new energy vehicles are becoming more and more popular, BMS and the stability of its operation have always been a topic of concern to users. If the running system cannot read or identify the high-voltage interlock status normally, it may have an immeasurable impact on users and even lead to serious safety accidents. One of the risks of electrical high-voltage systems is sudden power outages and loss of power in the car. The existence of high-voltage interlocks can not only monitor the natural loosening of the high-voltage circuit, provide alarm information to the vehicle controller before the high-voltage power is cut off, and reserve time for the vehicle system to take countermeasures, but also prevent human error. When manually disconnecting the connection, the voltage of the entire circuit is added to both ends of the breakpoint, breaking through the air and arcing.

[0047] In order to achieve high-voltage system safety, a common solution in related technologies is to use voltage-type or current-type high-voltage interlocking, and diagnose by detecting resistor voltage division or voltage drop on resistor, or pulse width modulation (PWM) detection. However, these methods cannot obtain whether the current high-voltage connector is connected normally after one of the pins (PIN) of the high-voltage interlock is short-grounded; when there is leakage current in the loop, there may be a false alarm of high-voltage interlocking fault.

[0048] 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, and 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 realized, 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 state when a short-to-ground fault occurs be solved, but also the accuracy of sampling can be improved, and the misdiagnosis caused by the influence of leakage current can be greatly reduced; after determining the resistance of the interlocking loop according to the bidirectional sampling detection, it is also possible to judge the current state of the interlocking in the loop, such as whether the current interlocking connection is reliable or the current interlocking is loose or has poor contact, thereby improving the reliability of the interlocking loop.

[0049] The various embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0050] 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, and the detection circuit 10 may include a current source circuit 101 and a processing circuit 102. The current source circuit 101 is connected to the first end of the interlock loop 20 to form a first current branch, and the current source circuit 101 is also connected to the second end of the interlock loop 20 to form a second current branch; wherein: The processing circuit 102 includes a first sampling terminal ADC1 and a second sampling terminal ADC2, the first sampling terminal ADC1 is connected to the first terminal of the interlocking loop 20, and the second sampling terminal ADC2 is connected to the second terminal of the interlocking loop 20; The processing circuit 102 is configured to obtain a first voltage collected when the first current branch is working through the first sampling terminal ADC1, obtain a second voltage collected when the second current branch is working through the second sampling terminal ADC2, and determine the resistance value of the interlocking loop 20 according to 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 value of the interlocking loop 20 is used to determine whether there is an abnormality in the interlocking loop 20.

[0051] 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 is opposite when the first current branch and the second current branch flow through the interlocking loop 20. Exemplarily, the first current branch can be a branch for forward current injection, and the second current branch can be a branch for reverse current injection; or, the first current branch can be a branch for reverse current injection, and the second current branch can be a branch for forward current injection.

[0052] In a specific implementation, Figure 1 For example, it can be defined that the current flows from the first end of the interlocking loop 20 to the second end of the interlocking loop 20 as the injection direction of the forward current, and flows from the second end of the interlocking loop 20 to the first end of the interlocking loop 20 as the injection direction of the reverse current. In this implementation, the first current branch is a branch for the forward current injection, and the second current branch is a branch for the reverse current injection.

[0053] In the embodiment of the present application, the processing circuit 102 may be a microprocessor or an MCU, which has the functions of signal acquisition and signal processing. 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 obtain a first voltage collected when the first current branch is working, and the second sampling terminal ADC2 is used to obtain a second voltage collected when the second current branch is working.

[0054] 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 value 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.

[0055] In addition, in the embodiment of the present application, the interlocking loop 20 is applied to a high voltage scenario, so the interlocking loop can also be called a "high voltage interlocking loop". 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 a low voltage; if the voltage of the device to the ground is above 1000V, it can be called a 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.

[0056] It should also be noted that the interlocking circuit 20 can be used to indicate whether there is an abnormality in the connection of the high-voltage connector in the high-voltage interlocking circuit, which can be specifically judged according to the resistance value of the interlocking circuit 20. In this way, after determining the resistance value of the interlocking circuit 20, it is possible to judge the current state of the interlock in the circuit, such as whether the current interlocking connection is reliable or the current interlocking connection is unreliable, such as the problem of looseness or poor contact.

[0057] That is to say, in the embodiment of the present application, the detection circuit 10 is connected to the interlocking loop 20, and a second current branch (such as a reverse current injection loop) with a current direction opposite to that of the first current branch is added to the detection circuit 10, so that bidirectional sampling detection of forward current injection and reverse current injection can be realized, 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, according to the bidirectional sampling detection, not only can the problem of being unable to obtain the interlocking connection state when a short-to-ground fault occurs be solved, but also the sampling accuracy can 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 according to 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 the current interlocking is loose or has poor contact, thereby improving the reliability of the interlocking loop.

[0058] In some embodiments, Figure 1 Based on the detection circuit 10 shown, see Figure 2 The detection circuit 10 may further include a grounding resistor R1, 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.

[0059] In the embodiments of the present application, grounding refers to establishing a good connection between the metal parts of a device or circuit and the ground through a conductive method to ensure the safety of people and equipment. In this process, the conductivity of the ground is fully utilized to introduce current into the ground, and the current is quickly dispersed to the ground through the underground conductor.

[0060] 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 to prevent electric shock hazards and equipment damage.

[0061] It should be noted that the value range of the grounding resistor R1 should be selected according to specific application scenarios 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.

[0062] It can be understood 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 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 reverse injection for the interlocking loop, respectively.

[0063] In one possible implementation, Figure 2 Based on the detection circuit 10 shown, see 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.

[0064] 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.

[0065] 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.

[0066] In the embodiment of the present application, 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 connecting a resistor with an appropriate resistance value (such as the first current limiting resistor R2), the current can be reduced to protect the components in the circuit, thereby effectively controlling the current to ensure the stability and safety of the circuit.

[0067] In some embodiments, see Figure 3 The detection circuit 10 may further include a switch circuit, the switch circuit including a first switch element K1 and a second switch element K2, and the first current source U1 and the first switch element are connected to the first end of the interlocking loop 20 to form a first current branch, and the first current source U1 and the second switch element K2 are connected to the second end of the interlocking loop 20 to form the second current branch. That is, the first switch element K1 is connected between the first current source U1 and the first end of the interlocking loop 20, and the second switch element K2 is connected between the first current source U1 and the second end of the interlocking loop 20.

[0068] In the embodiment of the present application, both the first switch element K1 and the second switch element K2 can be a switch tube, a triode, a metal-oxide semiconductor field-effect transistor (Metal-Oxide Semiconductor Field-Effect Transistor, MOSFET or MOS for short), an insulated gate bipolar transistor (Insulate-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 described by taking MOS tubes as examples.

[0069] 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. In this way, by controlling the on and off of the first switch element K1 and the second switch element K2, the current injection direction can be controlled, and bidirectional sampling of forward current injection and reverse current injection can be achieved, which can not only solve the problem of being unable to obtain the interlocking connection state when a short-to-ground fault occurs, but also improve the accuracy of sampling, greatly reducing the misdiagnosis caused by the influence of leakage current.

[0070] 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 inject a forward current into the interlock loop 20 based on the first current branch when the first switch element K1 is turned on and the second switch element K2 is turned off, and obtain the collected first voltage through the first sampling terminal ADC1; and the detection circuit 10 is also configured to inject a reverse current into the interlock loop 20 based on the second current branch when the first switch element K1 is turned off and the second switch element K2 is turned on, and obtain the collected second voltage through the second sampling terminal ADC2.

[0071] 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 do not work at the same time. In other words, the injection of the forward current and the injection of the reverse current do not occur at the same time. In this way, by controlling the on-off status of the first switch element K1 and the second switch element K2, the current injection direction can be changed to perform bidirectional sampling.

[0072] The first possible situation: Figure 4As shown, at this time, the first switch element K1 is turned on and the second switch element K2 is turned off. In this case, the first current branch is working and the second current branch is not working. At this time, the forward current is injected and sampled 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 greatly different from the expected current value I. Among them, 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.

[0073] 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 does not work, and the second current branch works. At this time, reverse current injection and sampling are performed through the second current branch. At this time, the load Rd of the interlocking loop is connected in series with the fourth resistor R4 that causes the leakage current, so the current flowing through the load Rd is about Ileak. However, since it is opposite to the direction of the first current injection, Ir'= -Ileak. At this time, subtracting the two can obtain the value after the leakage current is compensated Ir'' = Ir - Ir' = I – Ileak –(- Ileak) = I.

[0074] In this way, through 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 greatly reducing the system's misjudgment rate of faults.

[0075] That is to say, in the embodiment of the present application, due to the existence of the first switch element K1 and the second switch element K2, and 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, it is possible to achieve the first current branch and the second current branch working at different times; in this way, the current injection direction is changed by controlling the closing state of the first switch element K1 and the second switch element K2, so that 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 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 leakage current.

[0076] In another possible implementation, Figure 2 Based on the detection circuit 10 shown, see Figure 6 , the current source circuit 101 may include a first current source U1 and a second current source U2, wherein: The first current source U1 is connected to the first end of the interlocking loop 20 to form a first current branch; The second current source U2 is connected to the second end of the interlock loop 20 to form a second current branch.

[0077] 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 implemented, and compared with the single current source of the related art, the use of two current sources here can also continue to sample when a single current source fails, so as to detect whether there is an abnormality in the interlocking loop, thereby improving the stability of the system.

[0078] 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.

[0079] In the embodiment of the present application, the first current limiting resistor R2 or the second current limiting resistor R3 can be called a "protective resistor", which is usually located at the port of the current source (for example, the first current source U1 and the second current source U2), and plays the role of limiting the current size and dividing the voltage to protect the circuit safety.

[0080] 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 connecting a resistor with an appropriate resistance value (such as the first current limiting resistor R2), the current can be reduced to protect the components in the circuit, thereby effectively controlling the current to ensure the stability and safety of the circuit.

[0081] 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 according to 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 made here.

[0082] 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.

[0083] In an embodiment of the present application, the detection circuit 10 is configured to inject a forward current into the interlock loop 20 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 ADC1; and the detection circuit 10 is also configured to inject a reverse current into the interlock loop 20 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 ADC2.

[0084] 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 in the first level state, it indicates that the first current source U1 is in the enabled state, at which time the first current source U1 is working, and accordingly, the first current branch is working, and 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 in the second level state, it indicates that the first current source U1 is in the disabled state, at which time the first current source U1 is not working, and accordingly, the first current branch is not working, and at this time the first current source U1 cannot inject a forward current into the interlocking loop 20 via the first current branch.

[0085] In the embodiment of the present application, the second enable signal is used to characterize whether the second current source U2 is enabled, that is, whether the second current source U2 is working. Wherein, when the second enable signal is in the first level state, it indicates that the second current source U2 is in the enabled state, at which time the second current source U2 is working, and correspondingly, the second current branch is working, and 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 the second level state, it indicates that the second current source U2 is in the non-enabled state, at which time the second current source U2 is not working, and correspondingly, the second current branch is not working, and at this time the second current source U2 cannot inject a reverse current into the interlocking loop 20 via the second current branch.

[0086] 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".

[0087] Exemplarily, 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.

[0088] 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 realize 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 can not only solve the problem that normal sampling cannot be performed to determine the current interlocking connection state when a short-to-ground fault occurs, but also solve 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.

[0089] In another possible implementation, Figure 6 Based on the detection circuit 10 shown, see Figure 7 , the detection circuit 10 may further include a switch circuit, the switch circuit includes a third switch element K3 and a fourth switch element K4, and the first current source U1, the third switch element K3 and the first end of the interlocking loop 20 are connected to form a first current branch, and the second current source U2, the fourth switch element K4 and the second end of the interlocking loop 20 are connected to form a second current branch. That is, the third switch element K3 is connected between the first current source U1 and the first end of the interlocking loop 20, and the fourth switch element K4 is connected between the second current source U2 and the second end of the interlocking loop 20.

[0090] In the embodiment of the present application, both the third switch element K3 and the fourth switch 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 described by taking MOS tubes as examples.

[0091] In the embodiment of the present application, the third switch element K3 is located on the first current branch, and the fourth switch element K4 is located on the second current branch, so that the first current branch and the second current branch can work at different times. In this way, by controlling the on and off of the third switch element K3 and the fourth switch element K4, the current injection direction can also be controlled to achieve bidirectional sampling of forward current injection and reverse current injection, which can not only solve the problem of being unable to obtain the interlocking connection state when a short-to-ground fault occurs, but also improve the accuracy of sampling; using two current sources at the same time can also improve system stability.

[0092] 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 inject a forward current into the interlock loop 20 based on the first current branch when the third switch element K3 is turned on and the fourth switch element K4 is turned off, and obtain the collected first voltage through the first sampling terminal ADC1; and the detection circuit 10 is also configured to inject a reverse current into the interlock loop 20 based on the second current branch when the third switch element K3 is turned off and the fourth switch element K4 is turned on, and obtain the collected second voltage through the second sampling terminal ADC2.

[0093] 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 do not work at the same time. In other words, the injection of the forward current and the injection of the reverse current do not occur at the same time. In this way, by controlling the on-off status of the third switch element K3 and the fourth switch element K4, the current injection direction can be changed to perform bidirectional sampling.

[0094] The first possible situation: Figure 8 As 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 working and the second current branch is not working. At this time, the first current source U1 injects and samples the 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 greatly different from the expected current value I. Among them, 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.

[0095] The second possible situation: Fig. 9As 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 does not work, and the second current branch works. 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 that causes the leakage current, so the current flowing through the load Rd is about Ileak. However, since it is opposite to the direction of the first current injection, Ir'= - Ileak. At this time, subtracting the two can obtain the value after the leakage current is compensated Ir'' = Ir - Ir' = I –Ileak – (- Ileak) = I.

[0096] In this way, through two current sources and two samplings of positive and negative 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 greatly reducing the system's misjudgment rate of faults.

[0097] That is to say, in the embodiment of the present application, due to the presence of the third switch element K3 and the fourth switch element K4, and the first current source U1 and the third switch element K3 are located on the first current branch, and the second current source U2 and the fourth switch element K4 are located on the second current branch, it is possible to achieve that the first current branch and the second current branch do not work at the same time; in this way, the working states of the two current sources are switched by controlling the closing state of the third switch element K3 and the fourth switch 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 leakage current compensation through two samplings, solves the accuracy deviation caused by the leakage current, and thus improves the sampling accuracy, 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.

[0098] 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 a first current branch, and the second sampling terminal ADC2 is used to obtain a second voltage collected under a second current branch.

[0099] 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 also be provided in a microprocessor, which is not limited here.

[0100] It can also be understood that in the embodiment of the present application, the processing circuit 102 may further include a control unit, which is configured to send a switching signal to a switching element in the detection circuit 10 , or to send an enable signal to a current source in the detection circuit 10 .

[0101] In the embodiment of the present application, Figure 3 For example, at this time, the control unit can send switching signals to the first switch element K1 and the second switch element K2 respectively to control the on and off states of the first switch element K1 and the second switch element K2, thereby realizing bidirectional sampling of positive and negative current injection.

[0102] In the embodiment of the present 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, so as to realize bidirectional sampling of positive and negative current injection.

[0103] In the embodiment of the present application, Figure 7 For example, at this time, the control unit can send switching signals to the third switch element K3 and the fourth switch element K4 respectively to control the on and off states of the third switch element K3 and the fourth switch element K4, thereby realizing bidirectional sampling of positive and negative current injection.

[0104] The 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 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 state when a short-to-ground fault occurs be solved, but also the accuracy of sampling can be improved, and the misdiagnosis caused by the influence of leakage current can be greatly reduced; after determining the resistance of the interlocking loop according to the bidirectional sampling detection, it is also possible to judge the current state of the interlocking in the loop, such as whether the current interlocking connection is reliable or the current interlocking is loose or has poor contact, thereby improving the reliability of the interlocking loop.

[0105] In another embodiment of the present application, Fig.10 A flow chart of a detection method provided in an embodiment of the present application. Fig.10 As shown, the detection method may include: S1001, obtaining a first voltage collected when a first current branch is working and a second voltage collected when a second current branch is working.

[0106] In the embodiment of the present application, the detection method is applied to the detection circuit 10 described in the above embodiment, and the detection circuit 10 is connected to the interlocking loop. Among them, the current source circuit is connected to the first end of the interlocking loop to form a first current branch, and the current source circuit is connected to the second end of the interlocking loop to form a second current branch, and the first current branch and the second current branch do not work at the same time.

[0107] In some embodiments, the current source circuit may include a first current source, and the detection circuit may further include a first switch element and a second 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: When the first switch element is turned on and the second switch element is turned off, a forward current is injected into the interlocking loop based on the first current branch, and the collected first voltage is acquired through the first sampling terminal; and 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.

[0108] In the embodiment of the present application, the first switch element and the second switch element are not turned on at the same time. The first switch element is located on the first current branch, and the second switch element is located on the second current branch. In this way, by controlling the on and off of the first switch element and the second switch element, the current injection direction can be controlled to achieve bidirectional sampling of forward current injection and reverse current injection.

[0109] That is to say, in the embodiment of the present application, due to the presence of the first switch element and the second switch element, the first current branch and the second current branch can work at different times. In this way, the current injection direction is changed by controlling the on-off status of the first switch element and the second switch element, so that bidirectional sampling of forward current injection and reverse current injection can be achieved, which can not only solve the problem that normal sampling cannot be performed to determine the current interlocking connection state when a short-to-ground fault occurs, but also realize leakage current compensation through two samplings, solve the accuracy deviation caused by the leakage current, and thus improve the accuracy of sampling, and greatly reduce the misjudgment rate caused by the influence of leakage current.

[0110] In some embodiments, the current source circuit may include a first current source and a second current source, and the first current source includes a first enable terminal, and the second current source includes a second enable terminal. Accordingly, obtaining a first voltage collected when the first current branch is working and a second voltage collected when the second current branch is working may include: 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 at the first enable terminal is in the second level state and the second enable signal received at 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 acquired through the second sampling terminal.

[0111] 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 characterize whether the first current source is enabled, that is, whether the first current source is working. Wherein, when the first enable signal is in a first level state, it indicates that the first current source is in an enabled state, and the first current source is working at this time, 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 non-enabled state, and the first current source is not working at this time, 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.

[0112] 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 characterize whether the second current source is enabled, that is, whether the second current source is working. Wherein, when the second enable signal is in a first level state, it indicates that the second current source is in an enabled state, at which time the second current source is working, and correspondingly, the second current branch is working, then the second current source can inject a reverse current into the interlocking loop via the second current branch; when the second enable signal is in a second level state, it indicates that the second current source is in a non-enabled state, at which time the second current source is not working, and correspondingly, the second current branch is not working, then the second current source cannot inject a reverse current into the interlocking loop via the second current branch.

[0113] 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".

[0114] 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 can not only solve the problem that normal sampling cannot be performed to determine the current interlocking connection state when a short-to-ground fault occurs, but also solve 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.

[0115] 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: 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 the collected first voltage is acquired through the first sampling terminal; and 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.

[0116] In the embodiment of the present application, the third switch element and the fourth switch element are not turned on at the same time. The third switch element is located on the first current branch, and the fourth switch element is located on the second current branch, so that the first current branch and the second current branch can work at different times. In this way, by controlling the on and off of the third switch element and the fourth switch element, the current injection direction can also be controlled, and bidirectional sampling of forward current injection and reverse current injection can be achieved.

[0117] That is to say, in the embodiment of the present application, due to the presence of the third switch element and the fourth switch element, and the first current source and the third switch element are located on the first current branch, and the second current source and the fourth switch 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 switch element and the fourth switch 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 realizes leakage current compensation through two samplings, solves the accuracy deviation caused by the leakage current, and thus improves the sampling accuracy, 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.

[0118] S1002, determining a voltage difference between the first voltage and the second voltage.

[0119] 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.

[0120] In an embodiment of the present application, the first current branch and the second current branch have opposite current directions when flowing through the interlocking loop. In this way, after obtaining the first voltage and the second voltage sampled twice, the voltage values ​​at both ends of the load of the interlocking loop can be obtained, so that the voltage difference between the first voltage and the second voltage (i.e., the voltage drop caused by the load) can be calculated. Then, according to the voltage difference and the current value output by the current source circuit, the resistance formula of R=U / I can be used to calculate the resistance of the interlocking loop. Among them, the resistance of the interlocking loop can be used to determine whether there is an abnormality in the interlocking loop.

[0121] In some embodiments, after determining the resistance value of the interlocking loop, the detection method may further include: When the resistance value of the interlocking circuit is within a preset range, it is determined that there is no abnormality in the interlocking circuit; 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.

[0122] 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.

[0123] That is to say, in the embodiment of the present application, if the resistance of the interlocking loop is within the preset range, that is, the resistance of the interlocking loop is 0 ohms or a few ohms, then it can be determined that there is no abnormality in the interlocking loop, that is, the connection of the interlocking loop is reliable. If the resistance of the interlocking loop is greater than the upper limit of the preset range, that is, the resistance of the interlocking loop is large, then it can be determined that there is an abnormality in the interlocking loop, that is, the connection of the interlocking loop is unreliable, for example, the current interlock is loose or has poor contact.

[0124] The embodiment of the present application provides a detection method, through the detection circuit in the aforementioned embodiment, the first voltage collected when the first current branch is working and the second voltage collected when the second current branch is working are obtained; then the voltage difference between the first voltage and the second voltage is determined; then 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. In this way, based on the bidirectional sampling detection of forward current injection and reverse current injection, it can not only solve the problem that the interlocking connection state cannot be obtained 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 according to the bidirectional sampling detection, it is also possible to judge the current state of the interlocking in the loop, such as whether the current interlocking connection is reliable or the current interlocking is loose or has poor contact, thereby improving the reliability of the interlocking loop.

[0125] In yet another embodiment of the present application, Fig.11 A schematic diagram of the structure of a detection system provided in an embodiment of the present application. Fig.11 As shown, the detection system 110 may include an interlocking loop 20 and a circuit board 1101 , wherein the circuit board 1101 includes 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 .

[0126] In the 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, which can not only improve the stability of the system and solve the problem that the interlocking connection state cannot be obtained when a short-to-ground fault occurs, but also improve the accuracy of sampling, greatly reducing 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 state of the current interlock in the loop, such as whether the current interlocking connection is reliable or the current interlocking is loose or has poor contact, thereby improving the reliability of the interlocking loop.

[0127] In a specific embodiment, Fig.12 A schematic diagram of an application scenario of a detection system provided in an embodiment of the present application. Fig.12 As shown, the detection system 110 may include a BMU board 1201 and an interlocking 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.

[0128] In the embodiments of the present application, Fig.12 As shown, a current may be injected in a forward direction once and a current may be injected in a reverse direction once, and then the voltage values ​​obtained by the two samples may be subtracted to calculate the resistance value of the high voltage interlock.

[0129] In the embodiment of the present application, a new high voltage interlock detection solution is provided, and the specific description of the solution is as follows: (1) The first current source U1 will stably output a rated current value; (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); (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 determined according to a pre-agreed preset range, that is, whether there is an abnormality in the interlock circuit; (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.

[0130] It should be noted that if only one sampling channel is used, in the event of a short-to-ground fault, it will not be possible to sample normally and obtain the current state of the high-voltage interlock; and if only one sampling channel is used, there will be an accuracy deviation caused by leakage current, which may cause the system to make a misdiagnosis after receiving the sampled value. Based on this, the embodiment of the present application adds sampling detection of reverse current injection.

[0131] In a possible implementation, Fig.12 As shown, the current injection direction can be changed by controlling the closing conditions of the two switch elements to perform bidirectional sampling. The details are as follows: 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.

[0132] During the second sampling, the second switch element K2 can be closed, the first switch element K1 can be opened, and reverse current injection and sampling can be performed. At this time, the load Rd is connected in series with the fourth resistor R4 that causes the leakage current. The current flowing through the load Rd is about Ileak, but because it is in the opposite direction to the first current injection, Ir'= - Ileak. At this time, the value after the leakage current is compensated can be obtained by subtracting the two: Ir'' = Ir - Ir' = I – Ileak – (- Ileak) = I.

[0133] In this way, more accurate sampling values ​​can be obtained, which can significantly reduce the system's misjudgment rate of faults.

[0134] In another possible implementation, two current sources (such as the first current source U1 and the second current source U2) may be used to implement the bidirectional current injection function. This implementation has enhanced stability and can continue to provide sampling data to the sampling end of the processing circuit or the ADC chip when one current source fails or the output is unstable.

[0135] In the embodiments of the present application, the specific implementation of the aforementioned embodiments is described in detail through the aforementioned 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 realize forward and reverse detection. This can avoid the inability to obtain the interlocking connection state due to the short ground of the high-voltage interlocking loop, and can greatly reduce the misdiagnosis caused by the leakage current of 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 interlocking loop.

[0136] In yet another embodiment of the present application, the detection system may be applied to a BMS. Fig.13 The following is a schematic diagram of the structure of a battery management system provided in an embodiment of the present application. Fig.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 .

[0137] In yet another embodiment of the present application, Fig.14 The following is a schematic diagram of the structure of a battery pack provided in an embodiment of the present application. Fig.14 As shown, the battery pack 140 may include a battery 1401 and a battery management system 130 as described in the aforementioned embodiments. The battery management system 130 may 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 thereof.

[0138] 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.

[0139] In the embodiment 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 work. Here, the electric drive device may contain a battery pack, and the electric energy output by the battery pack inside can be controlled to supply power to the load.

[0140] For example, the electric drive device may be a new energy vehicle (such as an electric car), a ship, an electric motorcycle, an airplane, etc., and the load may be an electric device in the electric drive device. For example, if the electric drive device 100 is an electric car, the load may be a motor in the electric car, etc., and there is no limitation on this.

[0141] 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. Moreover, 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 disk storage and optical storage, etc.) containing computer-usable program codes.

[0142] 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 generate 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.

[0143] It should also be noted that in this application, the terms "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0144] 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.

[0145] The methods disclosed in several method embodiments provided in this application can be arbitrarily combined without conflict to obtain new method embodiments.

[0146] The features disclosed in several product embodiments provided in this application can be arbitrarily combined without conflict to obtain new product embodiments.

[0147] The features disclosed in several method or device embodiments provided in this application can be arbitrarily combined without conflict to obtain new method embodiments or device embodiments.

[0148] The above description is only a specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application.

Claims

1. A detection circuit, the detection circuit being 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 interlocking loop, and the second sampling terminal is connected to the second terminal of the interlocking loop; The processing circuit is configured to obtain a first voltage collected when the first current branch is working through the first sampling end, obtain a second voltage collected when the second current branch is working through the second sampling end, and determine the resistance value of the interlocking loop according to the voltage difference between the first voltage and the second voltage and the current value output by the current source circuit; wherein the resistance value of the interlocking loop is used to determine whether the interlocking loop is abnormal; wherein: When the current source circuit includes a first current source, the detection circuit further includes a switch circuit, the switch circuit includes a first switch element and a second switch element, and the first current source, the first switch element and the first end of the interlock loop are connected to form the first current branch, and the first current source, the second switch 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 case the current source circuit comprises 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 switch element is turned on and the second switch 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 interlocking loop based on the second current branch when the first switch element is turned off and the second switch element is turned on, and acquire 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 inject a forward current into the interlock loop based on the first current branch and acquire the collected first voltage through the first sampling terminal when the first enable signal is in a first level state and the second enable signal is in a second level state; 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 interlocking loop based on the first current branch, and acquire 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 interlocking loop based on the second current branch when the third switch element is turned off and the fourth switch element is turned on, and acquire 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: Applied to the detection circuit as claimed in any one of claims 1 to 6, wherein the detection circuit is connected to an interlocking loop; 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 value of the interlocking loop is determined according to the voltage difference and the 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.

8. The detection method according to claim 7, characterized in that: The current source circuit includes a first current source, and the detection circuit also includes a first switch element and a second switch element; The acquiring of a first voltage collected when the first current branch is working and a second voltage collected when the second current branch is working includes: When the first switch element is turned on and the second switch element is turned off, a forward current is injected into the interlocking loop based on the first current branch, and the collected first voltage is acquired 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 acquired 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, and the first current source includes a first enable terminal, and the second current source includes a second enable terminal; the acquiring of a first voltage collected when the first current branch is working and a second voltage collected when the second current branch is working 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 acquired 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 also includes a third switch element and a fourth switch element; The obtaining of a first voltage collected under the first current branch and a second voltage collected under the second current branch includes: 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 the collected first voltage is acquired 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 acquired through the second sampling terminal.

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

12. A battery pack, characterized in that: The battery pack comprises a battery and the battery management system as claimed in 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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