Relay sticking detection circuit, relay fault detection method and apparatus

Abstract

The application discloses a relay sticking detection circuit, a relay fault detection method and equipment. The circuit is applied to a battery management system containing an insulation detection circuit, and the circuit comprises a detection module connected between a ground end and a second end of a main negative relay, a first end of the main negative relay being connected with a negative electrode of a battery, and a second end of the main negative relay being connected with a load; a sampling module connected with a sampling resistor of an upper bridge arm and used for collecting a sampling voltage of the sampling resistor; and a controller connected with the sampling module and used for determining a switching state of the main negative relay based on the sampling voltage in the case that the upper bridge arm and the detection module are both turned on. According to the embodiment of the application, the sticking detection of the relay can be realized reliably and at low cost.

Description

Technical Field

[0001] This application belongs to the field of new energy vehicle technology, and in particular relates to a relay adhesion detection circuit, a relay fault detection method and equipment. Background Technology

[0002] With economic development and advancements in new energy technologies, new energy vehicles are becoming increasingly popular. Among these, the Battery Management System (BMS), as the energy hub of a new energy vehicle, directly impacts the vehicle's operational quality through its safety and reliability within the vehicle's electrical architecture.

[0003] Relays, acting as switches in the high-voltage bus circuit of a battery management system, are used to control the discharge of the system. However, these mechanical switches carry certain risks of failure. For example, if a relay becomes stuck together, it may lead to uncontrolled discharge and cause a safety accident.

[0004] Therefore, how to efficiently and reliably detect the sticking of relays in battery management systems is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] This application provides a relay adhesion detection circuit, a relay fault detection method, and a device, which can realize relay adhesion detection in a low-cost and reliable manner.

[0006] In a first aspect, embodiments of this application provide a relay adhesion detection circuit applied to a battery management system including an insulation detection circuit. The insulation detection circuit includes an upper bridge arm and a lower bridge arm, each comprising a bridge arm resistor, a switching unit, and a sampling resistor connected in series. The upper bridge arm is connected between the positive terminal of the battery and a ground terminal, and the lower bridge arm is connected between the negative terminal of the battery and a ground terminal. The circuit includes: a detection module connected between the ground terminal and a second terminal of a main negative relay; a first terminal of the main negative relay connected to the negative terminal of the battery, and a second terminal of the main negative relay connected to a load; a sampling module connected to the sampling resistor of the upper bridge arm for acquiring the sampling voltage of the sampling resistor; and a controller connected to the sampling module for determining the switching state of the main negative relay based on the sampling voltage when both the upper bridge arm and the detection module are conducting.

[0007] In one embodiment, the insulation detection circuit further includes a first insulation impedance and a second insulation impedance, wherein the first insulation impedance is the equivalent impedance between the positive terminal of the battery and the ground terminal, and the second insulation impedance is the equivalent impedance between the negative terminal of the battery and the ground terminal; and a controller is used to compare the sampled voltage with the first threshold voltage or the second threshold voltage, and determine the switching state of the main negative relay based on the comparison result; wherein the first threshold voltage is calculated based on the bridge arm resistance of the upper bridge arm, the sampling resistance, and the second insulation impedance, and the second threshold voltage is calculated based on the bridge arm resistance of the upper bridge arm, the sampling resistance, and the equivalent resistance of the detection module.

[0008] In one embodiment, the controller is configured to determine that the main negative relay is in an open state when the sampled voltage is less than or equal to a first threshold voltage, and to determine that the main negative relay is in a closed state when the sampled voltage is greater than or equal to a second threshold voltage.

[0009] In one implementation, the formula for calculating the first threshold voltage is:

[0010]

[0011] The formula for calculating the second threshold voltage is:

[0012]

[0013] Where Va is the first threshold voltage, RS is the sampling resistor of the upper bridge arm, RN is the second insulation impedance, R1 is the bridge arm resistance of the upper bridge arm, K1 is the first deviation parameter, Vb is the second threshold voltage, Rb is the equivalent resistance of the detection module, K2 is the second deviation parameter, and VP is the battery voltage.

[0014] In one embodiment, the detection module includes a first switching unit and a first detection resistor connected in series.

[0015] Secondly, embodiments of this application provide a vehicle system, including: a relay adhesion detection circuit as described in the first aspect or any embodiment of the first aspect; a communication module connected to the relay adhesion detection circuit for signal transmission; and a processor connected to the communication module for sending or receiving signals.

[0016] Thirdly, embodiments of this application provide a relay fault detection method, applied to the relay adhesion detection circuit in the first aspect or any embodiment of the first aspect. The method includes: when the insulation test result is normal, sending a conduction signal to the switching unit and the detection module in the upper bridge arm, and sending a disconnection signal to the switching unit in the lower bridge arm; acquiring the state of the main negative relay and determining the threshold voltage corresponding to the state of the main negative relay; acquiring the sampling voltage of the sampling resistor in the upper bridge arm; and obtaining the fault detection result of the main negative relay based on the sampling voltage and the threshold voltage.

[0017] In one embodiment, before acquiring the state of the main negative relay and determining the threshold voltage corresponding to the state of the main negative relay, the method further includes: determining the state of the main negative relay based on a target control signal of the main negative relay, wherein the target control signal is used to control the state of the main negative relay.

[0018] In one embodiment, the target control signal includes a first control signal for controlling the main negative relay to close and a second control signal for controlling the main negative relay to open; determining the state of the main negative relay based on the target control signal of the main negative relay includes: if the target control signal is determined to be the first control signal, determining the state of the main negative relay to be closed; if the target control signal is determined to be the second control signal, determining the state of the main negative relay to be open.

[0019] In one embodiment, the threshold voltage includes a first threshold voltage corresponding to the open state of the main negative relay and a second threshold voltage corresponding to the closed state of the main negative relay; based on the sampled voltage and the threshold voltage, the fault detection result of the main negative relay is obtained, including: if the sampled voltage is greater than the first threshold voltage, it is determined that the main negative relay has a first type of fault; if the sampled voltage is less than the second threshold voltage, it is determined that the main negative relay has a second type of fault.

[0020] Fourthly, embodiments of this application provide a relay fault detection device, the device comprising:

[0021] The transmitting module is used to send a conduction signal to the switch unit and the detection module in the upper bridge arm and a disconnection signal to the switch unit in the lower bridge arm when the insulation test result is normal.

[0022] The first acquisition module is used to acquire the state of the main negative relay and determine the threshold voltage corresponding to the state of the main negative relay;

[0023] The second acquisition module is used to acquire the sampling voltage of the sampling resistor in the upper bridge arm;

[0024] The determination module is used to obtain the fault detection result of the main negative relay based on the sampled voltage and the threshold voltage.

[0025] Fifthly, embodiments of this application provide a relay fault detection device, the device comprising: a processor and a memory storing computer program instructions; the processor, when executing the computer program instructions, implements the relay fault detection method of the third aspect or any embodiment of the third aspect.

[0026] Fifthly, a computer-readable storage medium storing computer program instructions, which, when executed by a processor, implement the relay fault detection method of the second aspect or any embodiment of the second aspect.

[0027] In a seventh aspect, embodiments of this application provide a computer program product in which instructions, when executed by a processor of an electronic device, cause the electronic device to perform a relay fault detection method as described in the third aspect or any of the embodiments of the third aspect.

[0028] The relay sticking detection circuit, relay fault detection method, and device of this application, in a battery management system including an insulation detection circuit, can obtain the sampling voltage of the sampling resistor through the sampling module when the controller determines that both the upper bridge arm and the detection module are conducting, and determine the switching state of the main and negative relays based on the sampling voltage. It is understood that in this application embodiment, by adding a detection module and a sampling module to the battery management system including the insulation detection circuit, efficient and reliable main and negative relay sticking detection is achieved with lower hardware costs. Furthermore, this process does not rely on DC-LINK capacitors, thereby enabling main and negative relay sticking detection in various scenarios, avoiding the introduction of additional risks, and improving the reliability of relay sticking detection. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This application shows an architecture diagram of a vehicle powertrain system provided in one embodiment;

[0031] Figure 2 A schematic diagram of a relay adhesion detection circuit according to an embodiment of this application is shown;

[0032] Figure 3 A schematic diagram of a relay adhesion detection circuit according to an embodiment of this application is shown;

[0033] Figure 4 A schematic diagram of a relay adhesion detection circuit according to an embodiment of this application is shown;

[0034] Figure 5 A schematic diagram of a relay adhesion detection circuit according to an embodiment of this application is shown;

[0035] Figure 6 An equivalent circuit diagram of the main negative relay being disconnected according to an embodiment of this application is shown;

[0036] Figure 7 A simplified equivalent circuit diagram of the main negative relay disconnection provided in one embodiment of this application is shown;

[0037] Figure 8 An equivalent circuit diagram of the closing of the main negative relay provided in one embodiment of this application is shown;

[0038] Figure 9 A simplified equivalent circuit diagram of the closing of the main negative relay provided in one embodiment of this application is shown;

[0039] Figure 10 A flowchart illustrating a relay fault detection method according to an embodiment of this application is shown;

[0040] Figure 11 A flowchart illustrating a relay fault detection method according to an embodiment of this application is shown;

[0041] Figure 12 A flowchart illustrating a relay fault detection method according to an embodiment of this application is shown;

[0042] Figure 13 This is an architecture diagram of a vehicle system provided in another embodiment of this application;

[0043] Figure 14 This is a schematic diagram of the structure of a relay fault detection device provided in another embodiment of this application;

[0044] Figure 15 This is a schematic diagram of the structure of a relay fault detection device provided in another embodiment of this application.

[0045] Explanation of reference numerals in the attached figures:

[0046] 100. Vehicle powertrain system; 11. Battery; 12. Main positive relay; 13. Load; 14. Main negative relay;

[0047] 200. Relay adhesion detection circuit; 210. Battery management system; 220. Upper bridge arm; 230. Lower bridge arm; 240. Detection module; 250. Sampling module; 260. Controller; R. Bridge arm resistor;

[0048] R1, upper bridge arm resistance; R2, lower bridge arm resistance; RS, sampling resistor; S, switching unit; S1, upper bridge arm switching unit; S2, lower bridge arm switching unit; RP, first insulation resistance; RN, second insulation resistance; S3, first switching unit; Rb, first detection resistor; RN0, third equivalent resistance; RP0, fourth equivalent resistance;

[0049] 1301. Communication module; 1302. Processor. Detailed Implementation

[0050] The features and exemplary embodiments of various aspects of this application will be described in detail below. To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain this application and not to limit it. For those skilled in the art, this application can be implemented without some of these specific details. The following description of the embodiments is merely to provide a better understanding of this application by illustrating examples.

[0051] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0052] With economic development and advancements in new energy technologies, new energy vehicles are becoming increasingly common. In the electrical architecture of new energy vehicles, the Battery Management System (BMS) serves as the vehicle's energy hub, and its safety and reliability directly impact vehicle performance. Furthermore, in the powertrain systems of new energy vehicles, relays are typically used as switches on the high-voltage bus circuit to control battery discharge. However, these mechanical switches carry certain risks of failure. For example, under load, they are prone to arcing, burning, and adhesion, which could lead to uncontrolled discharge and cause safety accidents.

[0053] Therefore, in order to ensure the safety of the power system, the condition detection of relays is indispensable. Figure 1This application illustrates an architecture diagram of a vehicle powertrain system 100 according to one embodiment, as shown below. Figure 1 As shown, the vehicle powertrain 100 includes at least a battery 11, a main positive relay 12, a load 13, and a main negative relay 14. The voltage output from the positive terminal of the battery 11 can be characterized as PACK+, the voltage output from the negative terminal of the battery 11 can be characterized as PACK-, the voltage connected to the positive terminal of the load 13 can be characterized as LINK+, and the voltage connected to the negative terminal of the load 13 can be characterized as LINK-.

[0054] In related technologies, when detecting adhesion of the main negative relay 14, the voltage change of LINK+ after the relay is closed can be used for judgment. It is understandable that during the initial connection of the positive and negative buses, the DC bus (Direct Current Link, DC-LINK) capacitor is in a charging state, and the LINK+ voltage is on an upward trend. Conversely, if the negative bus is not connected, the LINK+ voltage equals the PACK+ voltage. This allows determination of whether the main negative relay 14 is in an unexpected state. However, during offline testing of battery pack 11, the DC-LINK capacitor is absent in the power system, making it impossible to detect adhesion of the main negative relay 14.

[0055] Alternatively, in related technologies, an excitation source can be applied to the LINK- side to detect the potential change of LINK-, and the main negative relay 14 can be distinguished as being in a closed state by detecting the voltage value. However, the excitation source is a low voltage, and if connected in series in a DC bus electrical system, it is easy to cause current backflow and burn out the BMS.

[0056] Alternatively, in related technologies, PACK- and LINK- can be used separately to detect the voltage of PACK+. If the negative bus is connected, the PACK+ voltage can also be sampled using LINK- as ground. However, the above detection scheme requires dual isolated power supplies and isolated communication circuits, which increases the hardware cost of the BMS.

[0057] Therefore, how to achieve low-cost, high-reliability detection of adhesion of the main and negative relays 14 is a technical problem that urgently needs to be solved by those skilled in the art.

[0058] To address the problems of the prior art, embodiments of this application provide a relay adhesion detection circuit, a relay fault detection method, and a device. The relay adhesion detection circuit provided in this application embodiment will be described first below.

[0059] Figure 2A schematic diagram of a relay sticking detection circuit according to an embodiment of this application is shown. The relay sticking detection circuit 200 is applied to a battery management system 210 including an insulation detection circuit. The insulation detection circuit includes an upper bridge arm 220 and a lower bridge arm 230. Both the upper bridge arm 220 and the lower bridge arm 230 include a bridge arm resistor R, a switching unit S, and a sampling resistor RS connected in series. The upper bridge arm 220 is connected between the positive terminal of the battery 11 and the ground terminal GND, and the lower bridge arm 230 is connected between the negative terminal of the battery 11 and the ground terminal. Figure 2 As shown, the relay adhesion detection circuit 200 includes:

[0060] The detection module 240 is connected between the grounding terminal and the second terminal of the main negative relay 14; the first terminal of the main negative relay 14 is connected to the negative terminal of the battery 11, and the second terminal of the main negative relay 14 is connected to the load 13.

[0061] The sampling module 250 is connected to the sampling resistor RS of the upper bridge arm 220 and is used to collect the sampling voltage of the sampling resistor RS.

[0062] The controller 260, connected to the sampling module 250, is used to determine the switching state of the main negative relay 14 based on the sampling voltage when both the upper bridge arm 220 and the detection module 240 are turned on.

[0063] For example, the Battery Management System (BMS) may include an insulation detection circuit to ensure safe operation. This insulation detection circuit may include an upper arm 220 and a lower arm 230. The upper arm 220 is connected between the positive terminal of the battery 11 and the ground terminal, and is used to detect the equivalent insulation resistance between the positive terminal of the battery 11 and the vehicle body ground (i.e., the ground terminal). The lower arm 230 is connected between the negative terminal of the battery 11 and the ground terminal, and is used to detect the equivalent insulation resistance between the negative terminal of the battery 11 and the vehicle body ground.

[0064] Furthermore, the upper bridge arm 220 may include a bridge arm resistor R1, a switching unit S1, and a sampling resistor RS, all connected in series. The lower bridge arm 230 may include a lower bridge arm resistor R2, a switching unit S2, and a sampling resistor RS, all connected in series. It is understood that the resistance values ​​of the bridge arm resistors in the upper and lower bridge arms can be the same or different; similarly, the resistance values ​​of the sampling resistors in the upper and lower bridge arms can be the same or different.

[0065] For example, the grounding terminal can be a low-voltage grounding terminal, or the grounding terminal can be the vehicle housing grounding terminal.

[0066] In some optional embodiments, the insulation detection circuit deployed in the BMS in this application embodiment can be a balanced bridge insulation detection circuit, or the insulation detection circuit deployed in the BMS can also be an unbalanced bridge insulation detection circuit. In this application embodiment, a balanced bridge insulation detection circuit is used as an example for illustration, but its principle is also applicable to the unbalanced bridge insulation detection circuit. Therefore, the unbalanced bridge insulation detection circuit will not be described in detail.

[0067] For example, the detection module 240 is connected between the ground terminal and the second terminal of the main negative relay 14. The first terminal of the main negative relay 14 is connected to the negative terminal of the battery 11, and the second terminal of the main negative relay 14 is connected to the load 13.

[0068] For example, the detection module 240 can also be connected to the controller 260, which can be used to control the on / off state of the detection module 240.

[0069] For example, the sampling module 250 is connected to the sampling resistor RS of the upper bridge arm 220 to collect the sampling voltage of the sampling resistor RS.

[0070] For example, sampling module 250 can also be connected to controller 260 so that controller 260 can acquire the sampling voltage of sampling resistor RS. In one example, sampling module 250 may be the sampling module 250 corresponding to upper bridge arm 220 in an insulation detection circuit. For example, sampling module 250 may be the analog-to-digital converter (ADC) of upper bridge arm 220 in the insulation detection circuit, and the voltage acquired by sampling module 250 may be the voltage acquired by the ADC sampling channel.

[0071] It is understood that in this embodiment of the application, the sampling voltage corresponding to the sampling resistor RS is used as the basis for judging the switching state of the main negative relay 14. This reduces the requirement for the sampling circuit, that is, it reuses the existing hardware in the insulation detection circuit to obtain the sampling voltage, thereby reducing the circuit cost.

[0072] For example, the controller 260 is connected to the sampling module 250 and is used to determine the switching state of the main negative relay 14 based on the sampling voltage when both the upper bridge arm 220 and the detection module 240 are turned on.

[0073] For example, the controller 260 is connected to the switching units in the upper and lower bridge arms, and can control the on / off state of the upper and lower bridge arms by controlling the switching units in the upper and lower bridge arms. Furthermore, the controller 260 can also be connected to the detection module 240 to control the on / off state of the detection module 240.

[0074] For example, when the controller 260 determines that both the upper bridge arm 220 and the detection module 240 are on, it can obtain the sampling voltage of the sampling resistor RS through the sampling module 250 and determine the switching state of the main negative relay 14 based on the sampling voltage.

[0075] In this embodiment, in the battery management system 210 including an insulation detection circuit, the controller 260 can determine that both the upper bridge arm 220 and the detection module 240 are conducting, and then obtain the sampling voltage of the sampling resistor RS through the sampling module 250, and determine the switching state of the main negative relay 14 based on the sampling voltage. It is understood that in this embodiment, the battery management system 210 including the insulation detection circuit only requires the addition of the detection module 240 at the hardware level to achieve the detection of the main negative relay, thus achieving low-cost, efficient, and reliable detection of the main negative relay 14 sticking. Furthermore, the sampling module 250 used to obtain the sampling voltage can reuse existing components of the insulation detection circuit, further reducing costs. In addition, this process does not rely on a DC-LINK capacitor, enabling the detection of the main negative relay 14 sticking in various situations and avoiding the introduction of additional risks, thereby improving the reliability of relay sticking detection.

[0076] In order to determine the switching state of the main negative relay 14, as another implementation of this application, this application also provides another implementation of the relay adhesion detection circuit, as detailed in the following embodiments.

[0077] Figure 3 This application provides an embodiment of a relay adhesion detection circuit, which is illustrated in the following diagram. Figure 3 As shown, the relay adhesion detection circuit 200 further includes: a first insulation resistance RP and a second insulation resistance RN. The first insulation resistance RP is the equivalent impedance between the positive terminal of battery 11 and the ground terminal, and the second insulation resistance RN is the equivalent impedance between the negative terminal of battery 11 and the ground terminal.

[0078] For example, insulation resistance can be used to characterize the high-voltage electrical isolation state of the entire vehicle. Specifically, the first insulation resistance RP can characterize the isolation state of the positive terminal of battery 11 to ground. The second insulation resistance RN can be used to characterize the isolation state of the negative terminal of battery 11 to ground.

[0079] For example, both the first insulation impedance RP and the second insulation impedance RN can be an equivalent impedance, that is, the first insulation impedance RP and the second insulation impedance RN may not exist in physical form and are only used to characterize the isolation state of the vehicle.

[0080] In some embodiments, the controller 260 can be used to compare the acquired sampled voltage with a first threshold voltage or a second threshold voltage, and determine the switching state of the main negative relay 14 based on the comparison result. The first threshold voltage is calculated based on the bridge arm resistance R1 of the upper bridge arm, the sampling resistance RS, and the second insulation impedance RN, while the second threshold voltage is calculated based on the bridge arm resistance R1 of the upper bridge arm, the sampling resistance RS, and the equivalent resistance of the detection module 240.

[0081] In some optional embodiments, the controller 260 determines that the main negative relay 14 is in an open state when it determines that the sampled voltage is less than or equal to a first threshold voltage; and determines that the main negative relay 14 is in a closed state when it determines that the sampled voltage is greater than or equal to a second threshold voltage.

[0082] In this embodiment, the controller 260 can determine the on / off state of the main negative relay 14 by comparing the collected sampled voltage with a first threshold voltage and a second threshold voltage. That is, when the sampled voltage is less than or equal to the first threshold voltage, the main negative relay 14 is determined to be off; when the sampled voltage is greater than or equal to the second threshold voltage, the main negative relay 14 is determined to be on / off, thereby realizing the determination of the on / off state of the main negative relay 14.

[0083] In some alternative embodiments, due to the characteristics of the various components in the relay adhesion detection circuit 200, the first threshold voltage Va can be represented by the following formula (1), and the second threshold voltage Vb can be represented by the following formula (2):

[0084]

[0085] Where RS is the sampling resistor of the upper bridge arm, RN is the second insulation impedance, R1 is the bridge arm resistance of the upper bridge arm, K1 is the first deviation parameter, Rb is the equivalent resistance of the detection module, and K2 is the second deviation parameter.

[0086] The first deviation parameter and the second deviation parameter can be preset by technicians according to different needs. Furthermore, the values ​​of the first deviation parameter and the second deviation parameter can be the same or different.

[0087] In one example, the first deviation parameter could be +0.3, and the second deviation parameter could be -0.3.

[0088] In another example, both the first and second deviation parameters can be ±0.3, that is, when determining that the sampled voltage belongs to... When this is the case, it can be determined that the main negative relay 14 is disconnected; when it is determined that the sampling voltage belongs to... At that time, it can be determined that the main negative relay 14 is closed.

[0089] For example, the equivalent resistance of the detection module 240 can be used to characterize the voltage division effect of the detection module on the adhesion detection circuit.

[0090] In this embodiment, a corresponding deviation parameter is introduced when calculating the first threshold voltage and the second threshold voltage, thereby improving the stability of the detection of the main negative relay 14. It is understood that limitations exist in voltage and resistance detection due to instrument accuracy constraints. By reasonably introducing deviation parameters, risks can be mitigated in the early stages of circuit design, improving the stability and reliability of the relay adhesion detection circuit.

[0091] Furthermore, in this embodiment of the application, based on the structural features of the relay adhesion detection circuit 200, the first threshold voltage can be calculated using the bridge arm resistance R1 of the upper bridge arm and the sampling resistor RS, and the second threshold voltage can be calculated using the bridge arm resistance R1 of the upper bridge arm, the sampling resistor RS and the equivalent resistance of the detection module 240, thereby providing an accurate basis for judging the switching state of the main and negative relays 14.

[0092] Furthermore, in order to realize its detection function, as another implementation of this application, the detection module 240 also provides another implementation of the relay adhesion detection circuit 200, as detailed in the following embodiments.

[0093] Figure 4 This paper shows an architectural diagram of a relay adhesion detection circuit 200 provided in one embodiment of the present application, as follows: Figure 4 As shown, the detection module 240 includes a first switching unit S3 and a first detection resistor Rb connected in series.

[0094] For example, the first switching unit S3 and the first detection resistor Rb are connected in series between the ground terminal and the second terminal of the main negative relay 14.

[0095] In one example, the first terminal of the first switching unit S3 is connected to the ground terminal, and the second terminal of the first switching unit S3 is connected to the first terminal of the first sensing resistor Rb. The second terminal of the first sensing resistor Rb is connected to the second terminal of the main negative relay 14.

[0096] In another example, the first terminal of the first sensing resistor Rb is connected to the ground terminal, and the second terminal of the first sensing resistor Rb is connected to the first terminal of the first switching unit S3. The second terminal of the first switching unit S3 is connected to the second terminal of the main negative relay 14.

[0097] For example, the first switch unit S3 can be used to control the on / off state of the detection module 240. The first switch unit S3 also includes a control terminal, and the control terminal is connected to the controller 260. The controller 260 can control the on / off state of the first switch by sending different control signals to the first switch unit S3.

[0098] In one example, the first switching unit S3 can be a switching element that can isolate electrical circuits, such as an optocoupler switch or a reed switch.

[0099] For example, the value of the first sensing resistor Rb can be predetermined by a technician according to different sensing requirements. For instance, the technician can determine it based on the battery 11 voltage, the sampling resistor RS of the upper bridge arm 220, and the actual sampling requirements.

[0100] Furthermore, the first sensing resistor Rb can be composed of one or more resistors. For example, the first sensing resistor Rb can be obtained by connecting multiple resistors in series or in parallel. For example, the first sensing resistor Rb can be obtained by connecting four resistors with a resistance of 150 kΩ in series; or, the first sensing resistor Rb can be obtained by connecting three resistors with a resistance of 360 kΩ in series.

[0101] In this embodiment, the detection module includes a first switching unit S3 and a first detection resistor Rb. When relay adhesion detection is not required, the first switching unit S3 can be disconnected, allowing the insulation detection circuit to perform its insulation detection function. When relay adhesion detection is required, the detection module is activated to detect the adhesion of the main and negative relays 14. It is understood that in this implementation, by adding the first switching unit S3 and the first detection unit while ensuring the insulation detection function of the battery management system 210, adhesion detection of the main and negative relays 14 can be achieved at a lower cost.

[0102] For example, the following uses Figures 5 to 9 The following example illustrates a relay adhesion detection circuit.

[0103] Figure 5 This application provides an embodiment of a relay adhesion detection circuit, which is illustrated in the following diagram. Figure 5 As shown, when the upper bridge arm's switch unit S1 is closed, the first switch unit S3 in the detection module 240 is closed, the lower bridge arm's switch unit S2 is open, and the main negative relay 14 is open, Figure 5 The corresponding equivalent circuit diagram is as follows: Figure 6 As shown, Figure 6 An equivalent circuit diagram of the main negative relay 14 disconnected according to an embodiment of this application is shown. The sampling resistor RS of the upper bridge arm 220 is connected in series with the bridge arm resistor R1 of the upper bridge arm, and the series-connected RS and R1 are connected in parallel with the first insulation impedance RP. Further, the parallel-connected resistor is connected in series with the second insulation impedance RN.

[0104] Understandably, under normal insulation conditions, the second insulation impedance RN and the first insulation impedance RP approach infinity. Furthermore, considering the complex environment of the entire vehicle, it is possible to... Figure 6 The equivalent circuit diagram shown is simplified to obtain the simplified equivalent circuit diagram. Figure 7 A simplified equivalent circuit diagram of the main negative relay 14 disconnected according to an embodiment of this application is shown. Wherein, as Figure 7 As shown in the simplified circuit diagram, the sampling resistor RS of the upper bridge arm 220, the bridge arm resistor R1 of the upper bridge arm, and the second insulation impedance RN are connected in series.

[0105] Furthermore, it can be based on, for example Figure 7 The circuit diagram shown is used to calculate the theoretical voltage value corresponding to the main negative relay 14 when it is disconnected, that is, the first threshold voltage Va, and its expression is shown in the above formula (1).

[0106] Similarly, when the upper bridge arm's switch unit S1 is closed, the first switch unit S3 in the detection module 240 is closed, the lower bridge arm's switch unit S2 is open, and the main negative relay 14 is closed, Figure 5 The corresponding equivalent circuit diagram is as follows: Figure 8 As shown, Figure 8 An equivalent circuit diagram of the closed main negative relay 14 according to an embodiment of this application is shown. The sampling resistor RS of the upper bridge arm 220 is connected in series with the bridge arm resistor R1 of the upper bridge arm, and the series-connected RS and R1 are connected in parallel with the first insulation impedance RP. Further, the second insulation impedance RN is connected in parallel with the first detection resistor Rb and the third equivalent resistance RN0. The relay adhesion detection circuit 200 also includes a third equivalent resistance RN0 and a fourth equivalent resistance RP0. The third equivalent resistance RN0 can be used to characterize the equivalent resistance of the positive voltage connected to the load 13 side to the ground terminal; the fourth equivalent resistance RP0 can be used to characterize the equivalent resistance of the negative voltage connected to the load side to the ground terminal.

[0107] Understandably, under normal insulation conditions, the second insulation impedance RN, the first insulation impedance RP, the third equivalent resistance RN0, and the fourth equivalent resistance RP0 approach infinity. Furthermore, considering the complex environment of the entire vehicle, it is possible to... Figure 8 The equivalent circuit diagram shown is simplified to obtain the simplified equivalent circuit diagram. Figure 9 A simplified equivalent circuit diagram of the closing of the main negative relay 14 according to an embodiment of this application is shown. Wherein, as Figure 9 As shown in the simplified circuit diagram, the sampling resistor RS of the upper bridge arm 220, the bridge arm resistor R1 of the upper bridge arm, and the first detection resistor Rb are connected in series.

[0108] Furthermore, it can be based on, for example Figure 9The circuit diagram shown is used to calculate the theoretical voltage value corresponding to the closing of the main negative relay 14, that is, the first threshold voltage Vb, and its expression is shown in the above formula (2).

[0109] The above are specific embodiments of the relay adhesion detection circuit 200 provided in this application. The above-described relay adhesion detection circuit 200 can be used in the relay fault detection method provided in the following embodiments.

[0110] The relay fault detection method provided in the embodiments of this application is described below.

[0111] Figure 10 A flowchart illustrating a relay fault detection method according to an embodiment of this application is shown. Figure 10 As shown, relay fault detection methods include 1010-1040:

[0112] 1010. If the insulation test result is normal, send a conduction signal to the switch unit and the detection module in the upper bridge arm, and send a disconnection signal to the switch unit in the lower bridge arm.

[0113] For example, the controller 260 can determine the magnitude of the first insulation impedance RP and the second insulation impedance RN by controlling the switching units S in the upper and lower bridge arms of the insulation detection circuit, and determine that the insulation detection result is normal when the first insulation impedance RP and the second insulation impedance RN are determined to be greater than or equal to a preset impedance threshold.

[0114] For example, when the controller 260 determines that the insulation test result is normal, it can send a control signal to the switch unit S in the upper and lower bridge arms of the insulation test circuit to disable the insulation test function, so that the insulation test circuit stops performing the insulation test function.

[0115] For example, if the insulation test result is normal, the controller 260 can send a conduction signal to the switch unit S in the upper bridge arm 220 and the detection module 240, and send a disconnection signal to the switch unit S in the lower bridge arm 230, so that both the upper bridge arm 220 and the detection module 240 are in a conducting state.

[0116] 1020. Obtain the state of the main negative relay and determine the threshold voltage corresponding to the state of the main negative relay.

[0117] For example, the controller 260 can acquire the state of the main negative relay 14 and determine the threshold voltage corresponding to the state of the main negative relay 14.

[0118] In one example, controller 260 can determine that the main negative relay 14 is in a closed state; or, controller 260 can determine that the main negative relay 14 is in an open state. Furthermore, different states of the main negative relay 14 can correspond to different threshold voltages.

[0119] 1030. Obtain the sampling voltage of the sampling resistor in the upper bridge arm.

[0120] For example, the controller 260 can obtain the sampling voltage corresponding to the sampling resistor RS through the sampling module 250. The sampling voltage corresponding to the sampling resistor RS can be used to characterize the state of the main negative relay 14.

[0121] 1040. Based on the sampled voltage and the threshold voltage, the fault detection result of the main negative relay is obtained.

[0122] For example, the fault detection result of the main negative relay 14 can be determined based on the sampled voltage used to characterize the state of the main negative relay 14 and the threshold voltage corresponding to the state of the main negative relay 14.

[0123] In this embodiment, when the insulation test result is normal, a conduction signal is sent to the switching unit S in the upper bridge arm 220 and the detection module 240, and a disconnection signal is sent to the switching unit S in the lower bridge arm 230. The state of the main negative relay 14 and the sampling voltage of the sampling resistor RS in the upper bridge arm 220 are acquired, and a threshold voltage corresponding to the state of the main negative relay 14 is determined based on the state of the main negative relay 14. Further, based on the sampling voltage and the threshold voltage, the fault detection result of the main negative relay 14 is obtained. Thus, by utilizing the sampling voltage of the sampling resistor RS and the threshold voltage corresponding to the state of the main negative relay 14, accurate fault detection of the main negative relay 14 can be achieved.

[0124] Furthermore, in order to determine the state of the main negative relay 14, as another implementation of this application, this application also provides another implementation of the relay fault detection method, as detailed in the following embodiments.

[0125] Figure 11 A flowchart illustrating a relay fault detection method according to an embodiment of this application is shown. Figure 11 As shown, the relay fault detection method includes the following steps:

[0126] 1110. If the insulation test result is normal, send a conduction signal to the switch unit and the detection module in the upper bridge arm, and send a disconnection signal to the switch unit in the lower bridge arm.

[0127] 1120. Determine the state of the main and negative relays based on the target control signal of the main and negative relays.

[0128] 1130. Obtain the state of the main negative relay and determine the threshold voltage corresponding to the state of the main negative relay.

[0129] 1140. Obtain the sampling voltage of the sampling resistor in the upper bridge arm.

[0130] 1150. Based on the sampled voltage and the threshold voltage, the fault detection result of the main negative relay is obtained.

[0131] For example, step S1110 is the same as step S1010, and steps S1130-S1150 are the same as steps S1020-S1040, which will not be described in detail here.

[0132] For example, the controller 260 can send a target control signal to the main negative relay 14 to control the state of the main negative relay 14. The target control signal is used to control the state of the main negative relay 14.

[0133] Furthermore, the state of the main negative relay 14 can be determined based on the target control signal of the main negative relay 14.

[0134] For example, the target control signal may include a first control signal for controlling the closing of the main negative relay 14 and a second control signal for controlling the opening of the main negative relay 14.

[0135] In some optional embodiments, if the target control signal is determined to be the first control signal, the state of the main negative relay 14 is determined to be the closed state; if the target control signal is determined to be the second control signal, the state of the main negative relay 14 is determined to be the open state.

[0136] For example, the controller 260 can determine the state of the main negative relay 14 based on the target control signal output to the main negative relay 14. If it is determined that a first control signal will be output to the main negative relay 14, the state of the main negative relay 14 can be determined to be closed; if it is determined that a second control signal will be output to the main negative relay 14, the state of the main negative relay 14 can be determined to be open.

[0137] In this embodiment, the state of the main negative relay 14 can be determined based on the first control signal and the second control signal output by the controller 260 to the main negative relay 14. It is understood that the target control signal output by the controller 260 can accurately determine the control state of the main negative relay 14, and using the target control signal output by the controller 260 as the criterion for determining the state of the main negative relay 14 eliminates the need for other devices, resulting in higher timeliness and accuracy.

[0138] For example, different states of the main negative relay 14 can correspond to different threshold voltages, wherein the threshold voltages include a first threshold voltage corresponding to the open state of the main negative relay 14 and a second threshold voltage corresponding to the closed state of the main negative relay 14.

[0139] In order to determine the fault type of the main negative relay 14, as another implementation of this application, this application also provides another implementation of the relay fault detection method, as detailed in the following embodiments.

[0140] Figure 12 A flowchart illustrating a relay fault detection method according to an embodiment of this application is shown. Figure 12 As shown, the relay fault detection method includes the following steps:

[0141] 1210. If the insulation test result is normal, send a conduction signal to the switch unit S and the detection module in the upper bridge arm, and send a disconnection signal to the switch unit in the lower bridge arm.

[0142] 1220. Obtain the state of the main negative relay and determine the threshold voltage corresponding to the state of the main negative relay.

[0143] 1230. Obtain the sampling voltage of the sampling resistor in the upper bridge arm.

[0144] 1241. If the sampled voltage is greater than the first threshold voltage, it is determined that the main negative relay has a first type of fault.

[0145] 1242. If the sampled voltage is less than the second threshold voltage, it is determined that the main negative relay has a second type of fault.

[0146] For example, steps S1210-S1230 are the same as steps S1010-S1030, and will not be described in detail here.

[0147] In some embodiments, in S1241, if it is determined that the main negative relay 14 is in an open state, the sampled voltage can be compared with a first threshold voltage. If it is determined that the sampled voltage is greater than the first threshold voltage, it is determined that the main negative relay 14 has a first type of fault. The first type of fault may be that the main negative relay 14 is not in an open state, i.e., the main negative relay 14 is stuck. If it is determined that the sampled voltage is less than or equal to the first threshold voltage, it is determined that the main negative relay 14 is in an open state, i.e., the main negative relay 14 does not have a sticking fault.

[0148] In some embodiments, in S1242, if it is determined that the main negative relay 14 is in a closed state, the sampled voltage can be compared with a second threshold voltage. If it is determined that the sampled voltage is less than a first threshold voltage, it is determined that the main negative relay 14 has a second type of fault. The second type of fault could be that the main negative relay 14 is not in a closed state, i.e., the main negative relay 14 cannot close. If it is determined that the sampled voltage is greater than or equal to the second threshold voltage, it is determined that the main negative relay 14 is in a closed state, i.e., the main negative relay 14 does not have a fault that prevents it from closing.

[0149] In this embodiment of the application, the fault type of the main negative relay 14 is determined by comparing the sampled voltage with the first threshold voltage or the second threshold voltage corresponding to different states of the main negative relay 14, thereby realizing the fault detection of the main negative relay 14 conveniently and accurately.

[0150] Furthermore, this application also provides a vehicle system in its embodiments. Figure 13 This is an architecture diagram of a vehicle system provided in another embodiment of this application, such as... Figure 13 As shown, the vehicle system includes:

[0151] The above embodiments include any of the following: a relay adhesion detection circuit 200; a communication module 1301 connected to the relay adhesion detection circuit for signal transmission; and a processor 1302 connected to the communication module for sending or receiving signals.

[0152] The communication module 1301 can be connected to the relay adhesion detection circuit 200 and the processor 1302 via a Controller Area Network (CAN) bus. It is understood that the use of the CAN bus for communication in this embodiment is for illustrative purposes only; communication can also be achieved via Bluetooth or 4G networks. Therefore, this embodiment does not limit the communication method of the communication module.

[0153] For example, the communication module can synchronize the state of the main negative relay determined by the controller in the relay adhesion detection circuit 200 to the processor 1302. Furthermore, the communication module can also synchronize the vehicle insulation state determined by the insulation detection circuit in the relay adhesion detection circuit 200 to the processor 1302.

[0154] In this embodiment, the vehicle system's intelligence is enhanced by constructing a vehicle system that includes a relay adhesion detection circuit, a communication module, and a processor.

[0155] Based on the relay fault detection method provided in the above embodiments, this application also provides specific implementation methods of a relay fault detection device. Please refer to the following embodiments.

[0156] First see Figure 14 , Figure 14 This is a schematic diagram of a relay fault detection device provided in another embodiment of this application. The relay fault detection device provided in this embodiment includes the following modules:

[0157] The transmitting module 1401 is used to send a conduction signal to the switch unit and the detection module in the upper bridge arm and a disconnection signal to the switch unit in the lower bridge arm when the insulation test result is normal.

[0158] The first acquisition module 1402 is used to acquire the state of the main negative relay and determine the threshold voltage corresponding to the state of the main negative relay.

[0159] The second acquisition module 1403 is used to acquire the sampling voltage of the sampling resistor in the upper bridge arm;

[0160] The determination module 1404 is used to obtain the fault detection result of the main negative relay based on the sampled voltage and the threshold voltage.

[0161] As one implementation of this application, before acquiring the state of the main negative relay and determining the threshold voltage corresponding to the state of the main negative relay, the device further includes: the first acquisition module is further configured to determine the state of the main negative relay based on the target control signal of the main negative relay, wherein the target control signal is used to control the state of the main negative relay.

[0162] As one implementation of this application, the target control signal includes a first control signal for controlling the main negative relay to close and a second control signal for controlling the main negative relay to open; the first acquisition module determines the state of the main negative relay based on the target control signal of the main negative relay in the following manner: if the target control signal is determined to be the first control signal, the state of the main negative relay is determined to be the closed state; if the target control signal is determined to be the second control signal, the state of the main negative relay is determined to be the open state.

[0163] As one implementation of this application, the threshold voltage includes a first threshold voltage corresponding to the open state of the main negative relay and a second threshold voltage corresponding to the closed state of the main negative relay; the determining module 1404 obtains the fault detection result of the main negative relay based on the sampled voltage and the threshold voltage in the following manner: if the sampled voltage is greater than the first threshold voltage, it is determined that the main negative relay has a first type of fault; if the sampled voltage is less than the second threshold voltage, it is determined that the main negative relay has a second type of fault.

[0164] Figure 15 A schematic diagram of the hardware structure of the relay fault detection device provided in an embodiment of this application is shown.

[0165] The relay fault detection device may include a processor 1501 and a memory 1502 storing computer program instructions.

[0166] Specifically, the processor 1501 may include a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits that can be configured to implement the embodiments of this application.

[0167] Memory 1502 may include mass storage for data or instructions. For example, and not limitingly, memory 1502 may include a hard disk drive (HDD), floppy disk drive, flash memory, optical disk, magneto-optical disk, magnetic tape, or Universal Serial Bus (USB) drive, or a combination of two or more of these. Where appropriate, memory 1502 may include removable or non-removable (or fixed) media. Where appropriate, memory 1502 may be internal or external to the integrated gateway disaster recovery device. In a particular embodiment, memory 1502 is non-volatile solid-state memory.

[0168] Memory may include read-only memory (ROM), random access memory (RAM), disk storage media devices, optical storage media devices, flash memory devices, and electrical, optical, or other physical / tangible memory storage devices. Therefore, typically, memory includes one or more tangible (non-transitory) computer-readable storage media (e.g., memory devices) encoded with software including computer-executable instructions, and when the software is executed (e.g., by one or more processors), it is operable to perform the operations described with reference to the methods according to one aspect of this disclosure.

[0169] The processor 1501 reads and executes computer program instructions stored in the memory 1502 to implement any of the relay fault detection methods in the above embodiments.

[0170] In one example, the relay fault detection device may also include a communication interface 1503 and a bus 1510. Wherein, as Figure 15 As shown, the processor 1501, memory 1502, and communication interface 1503 are connected through bus 1510 and complete communication with each other.

[0171] The communication interface 1503 is mainly used to realize communication between various modules, devices, units and / or equipment in the embodiments of this application.

[0172] Bus 1510 includes hardware, software, or both, that couples components of an online data traffic metering device together. For example, and not limitingly, the bus may include an Accelerated Graphics Port (AGP) or other graphics bus, an Enhanced Industry Standard Architecture (EISA) bus, a Front Side Bus (FSB), HyperTransport (HT) interconnect, an Industry Standard Architecture (ISA) bus, an Infinite Bandwidth Interconnect, a Low Pin Count (LPC) bus, a memory bus, a Microchannel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCI-X) bus, a Serial Advanced Technology Attachment (SATA) bus, a Video Electronics Standards Association Local (VLB) bus, or other suitable buses, or combinations of two or more of these. Where appropriate, bus 1510 may include one or more buses. Although specific buses are described and illustrated in embodiments of this application, any suitable bus or interconnect is contemplated herein.

[0173] This relay fault detection device can execute the relay fault detection method in this application embodiment based on the sampled voltage, thereby achieving a combination of Figure 10 and Figure 13 The method for detecting relay faults is described.

[0174] Furthermore, in conjunction with the relay fault detection methods described in the above embodiments, this application embodiment can provide a computer storage medium for implementation. The computer storage medium stores computer program instructions; when these computer program instructions are executed by a processor, they implement any of the relay fault detection methods described in the above embodiments.

[0175] This application also provides a computer program product, including a computer program that, when executed, implements any of the relay fault detection methods described in the above embodiments.

[0176] It should be clarified that this application is not limited to the specific configurations and processes described above and shown in the figures. For the sake of brevity, detailed descriptions of known methods are omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of this application is not limited to the specific steps described and shown. Those skilled in the art can make various changes, modifications, and additions, or change the order of steps, after understanding the spirit of this application.

[0177] The functional blocks shown in the above-described structural diagram can be implemented as hardware, software, firmware, or a combination thereof. When implemented in hardware, they can be, for example, electronic circuits, application-specific integrated circuits (ASICs), appropriate firmware, plug-ins, function cards, etc. When implemented in software, the elements of this application are programs or code segments used to perform the required tasks. Programs or code segments can be stored on a machine-readable medium or transmitted over a transmission medium or communication link via data signals carried on a carrier wave. "Machine-readable medium" can include any medium capable of storing or transmitting information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROM, flash memory, erasable ROM (EROM), floppy disks, CD-ROMs, optical disks, hard disks, fiber optic media, radio frequency (RF) links, etc. Code segments can be downloaded via computer networks such as the Internet, intranets, etc.

[0178] It should also be noted that the exemplary embodiments mentioned in this application describe methods or systems based on a series of steps or apparatus. However, this application is not limited to the order of the above steps; that is, the steps can be performed in the order mentioned in the embodiments, or in a different order, or several steps can be performed simultaneously.

[0179] The aspects of this disclosure have been described above with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this disclosure. It should be understood that each block in the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, 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, or other programmable data processing apparatus to produce a machine such that these instructions, executable via the processor of the computer or other programmable data processing apparatus, enable the implementation of the functions / actions specified in one or more blocks of the flowchart illustrations and / or block diagrams. Such a processor can be, but is not limited to, a general-purpose processor, a special-purpose processor, a special application processor, or a field-programmable logic circuit. It is also understood that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can also be implemented by special-purpose hardware performing the specified functions or actions, or can be implemented by a combination of special-purpose hardware and computer instructions.

[0180] The above description is merely a specific implementation of this application. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, modules, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. It should be understood that the protection scope of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the protection scope of this application.

Claims

1. A relay adhesion detection circuit, characterized in that, An application is made in a battery management system including an insulation detection circuit, wherein the insulation detection circuit includes an upper bridge arm and a lower bridge arm, each including a bridge arm resistor, a switching unit, and a sampling resistor connected in series, wherein the upper bridge arm is connected between the positive terminal of the battery and the ground terminal, and the lower bridge arm is connected between the negative terminal of the battery and the ground terminal, the circuit including: A detection module is connected between the grounding terminal and the second terminal of the main negative relay; the first terminal of the main negative relay is connected to the negative terminal of the battery, and the second terminal of the main negative relay is connected to the load. A sampling module, connected to the sampling resistor of the upper bridge arm, is used to acquire the sampling voltage of the sampling resistor; A controller, connected to the sampling module, is used to determine the switching state of the main negative relay based on the sampling voltage when both the upper bridge arm and the detection module are on and the lower bridge arm is off. The insulation detection circuit further includes a first insulation impedance and a second insulation impedance, wherein the first insulation impedance is the equivalent impedance between the positive terminal of the battery and the ground terminal, and the second insulation impedance is the equivalent impedance between the negative terminal of the battery and the ground terminal. The controller is used to compare the sampled voltage with a first threshold voltage or a second threshold voltage, and determine the switching state of the main negative relay based on the comparison result; wherein, the first threshold voltage is calculated based on the bridge arm resistance of the upper bridge arm, the sampling resistance and the second insulation impedance, and the second threshold voltage is calculated based on the bridge arm resistance of the upper bridge arm, the sampling resistance and the equivalent resistance of the detection module.

2. The circuit according to claim 1, characterized in that, The controller is configured to determine that the main negative relay is in an open state when the sampled voltage is less than or equal to the first threshold voltage, and to determine that the main negative relay is in a closed state when the sampled voltage is greater than or equal to the second threshold voltage.

3. The circuit according to claim 2, characterized in that, The formula for calculating the first threshold voltage is: ； The formula for calculating the second threshold voltage is: ； in, The first threshold voltage, The sampling resistor of the upper bridge arm. The second insulation resistance, The bridge arm resistance of the upper bridge arm, This is the first deviation parameter; This is the second threshold voltage; Let be the equivalent resistance of the detection module. This is the second deviation parameter; This refers to the battery voltage.

4. The circuit according to claim 1, characterized in that, The detection module includes a first switching unit and a first detection resistor connected in series.

5. A vehicle system, characterized in that, include: The relay adhesion detection circuit according to any one of claims 1-4; The communication module is connected to the relay adhesion detection circuit and is used for signal transmission; The processor, connected to the communication module, is used to send or receive signals.

6. A relay fault detection method, characterized in that, The method, applied to the relay adhesion detection circuit according to any one of claims 1-4, comprises: If the insulation test result is normal, a conduction signal is sent to the switch unit and the detection module in the upper bridge arm, and a disconnection signal is sent to the switch unit in the lower bridge arm. Obtain the state of the main negative relay and determine the threshold voltage corresponding to the state of the main negative relay; Obtain the sampling voltage of the sampling resistor in the upper bridge arm; The fault detection result of the main negative relay is obtained based on the sampled voltage and the threshold voltage.

7. The method according to claim 6, characterized in that, Before acquiring the state of the main negative relay and determining the threshold voltage corresponding to the state of the main negative relay, the method further includes: The state of the main negative relay is determined based on the target control signal of the main negative relay, wherein the target control signal is used to control the state of the main negative relay.

8. The method according to claim 7, characterized in that, The target control signal includes a first control signal for controlling the closing of the main negative relay and a second control signal for controlling the opening of the main negative relay; The process of determining the state of the main negative relay based on the target control signal of the main negative relay includes: If the target control signal is determined to be the first control signal, the state of the main negative relay is determined to be closed. If the target control signal is determined to be the second control signal, the state of the main negative relay is determined to be the open state.

9. The method according to any one of claims 6-8, characterized in that, The threshold voltage includes a first threshold voltage corresponding to the open state of the main negative relay and a second threshold voltage corresponding to the closed state of the main negative relay; The step of obtaining the fault detection result of the main negative relay based on the sampled voltage and the threshold voltage includes: If the sampled voltage is greater than the first threshold voltage, it is determined that the main negative relay has a first type of fault; If the sampled voltage is less than the second threshold voltage, it is determined that the main negative relay has a second type of fault.

10. A relay fault detection device, characterized in that, The device includes: a processor; When the processor executes computer program instructions, it implements the relay fault detection method as described in any one of claims 6-9.

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