A high-voltage interlock signal detection system and method

Abstract

The present invention relates to the technical field of battery management modules, and particularly to a high-voltage interlock signal detection system and method. A high-voltage interlock signal detection system includes a reference power supply, a voltage division diagnosis module, a constant current source, and an external circuit; the voltage division diagnosis module includes a current limiting unit, a voltage division unit, a diagnosis unit, and a diagnosis resistor; the output terminal of the power supply is connected to the input terminal of the current limiting unit, the external circuit and the constant current source are sequentially connected from the output terminal of the current limiting unit to the first grounding terminal, the voltage division unit is connected from the output terminal of the current limiting unit to the second grounding terminal, the external circuit is connected in parallel with the diagnosis resistor, and the input terminal of the diagnosis unit is connected to the voltage sampling point V1 of the voltage division unit for detecting the voltage value of the voltage sampling point V1 and diagnosing the circuit connection state of the external circuit according to the voltage value of the voltage sampling point V1. After adopting the above technical solution, fewer circuit components are used, the introduced sampling error is smaller, the diagnosis scheme is simple, and fewer resources of the MCU are occupied.

Description

Technical Field

[0001] The present invention relates to the technical field of battery management modules, and in particular to a high-voltage interlock signal detection system and method. Background Art

[0002] With the advancement of the new energy strategy, new energy vehicles have developed rapidly. In the high-voltage system of new energy vehicles, there are voltages exceeding 500 volts and currents of hundreds of amperes. These high voltages and high currents pose severe challenges to the operation, maintenance, and repair safety of high-voltage components. Therefore, it is very important to detect the state of the entire high-voltage circuit.

[0003] Currently, the method of using a high-voltage interlock loop is mainly adopted, that is: all branches connected to the high-voltage bus on an electric vehicle are connected in series by using a low-voltage wire harness, and then the integrity of the electrical connection of the high-voltage circuit is detected through a low-voltage signal. As Figure 1 shown, the voltages of V1, V2, V3, V4, V5, V6, and V7 are sampled, and the state of the external loop (ground short or power short) is judged by the numerical range of the sampled voltage. By calculating the resistance values of SEG1 and SEG2, it is judged whether the external loop is open, and the current flowing through R1, R3, and R5 is calculated to judge other faults (except ground short, power short, and open circuit). This solution: the circuit is complex, there are many resistors, and the economic cost is high; there are many sampling points, the introduced voltage sampling error is relatively large, and the errors introduced by subsequent resistance and current calculations will also increase; the diagnostic scheme is complex and prone to misjudgment. In addition, multiple resistance and current calculations are required, and the resource occupancy rate of the single-chip microcomputer is high.

[0004] Therefore, how to provide a high-voltage interlock signal detection system and method with fewer circuit components, less introduced sampling error, and a simple diagnostic scheme has become a technical problem to be solved. Summary of the Invention

[0005] In order to overcome the above technical defects, the purpose of the present invention is to provide a high-voltage interlock signal detection system and method, which solves the technical problems in the prior art of complex circuit, many resistors, high economic cost, many sampling points, relatively large introduced voltage sampling error, complex diagnostic scheme, prone to misjudgment, and high resource occupancy rate of the single-chip microcomputer.

[0006] The present invention discloses a high-voltage interlock signal detection system, which includes a reference power supply, a voltage division diagnosis module, a constant current source, and an external circuit; the voltage division diagnosis module includes a current limiting unit, a voltage division unit, a diagnosis unit, and a diagnosis resistor; the output terminal of the reference power supply is connected to the input terminal of the current limiting unit, the external circuit and the constant current source are sequentially connected from the output terminal of the current limiting unit to the first grounding terminal, and the voltage division unit is connected from the output terminal of the current limiting unit to the second grounding terminal; wherein, the external circuit is connected in parallel with the diagnosis resistor, the input terminal of the diagnosis unit is connected to the voltage sampling point V1 of the voltage division unit, and the diagnosis unit is used to detect the voltage value of the voltage sampling point V1, and diagnose the circuit connection state of the external circuit according to the voltage value of the voltage sampling point V1 and the calculated voltage value range.

[0007] Further, the circuit connection state of the external circuit includes five states: normal closed, open circuit fault, short circuit to ground fault, short circuit to power supply fault, and other faults. The diagnosis unit is used to calculate the voltage value ranges corresponding to the five states one by one according to the circuit connection relationship of the detection system. When the detected voltage value of the voltage sampling point V1 falls into a voltage value range, it is diagnosed that the external circuit is in the circuit connection state corresponding to the voltage value range; wherein, the other faults refer to circuit faults other than open circuit faults, short circuit to ground faults, and short circuit to power supply faults that occur in the external circuit.

[0008] Further, the diagnosis unit is used to diagnose the external circuit in sequence according to the five states of normal closed, open circuit fault, short circuit to ground fault, short circuit to power supply fault, and other faults. If it is diagnosed that the external circuit is in one of the four fault states other than normal closed, the diagnosis ends, otherwise the next round of diagnosis continues.

[0009] Further, the voltage division unit includes a voltage division resistor R2 and a voltage division resistor R3. The voltage division resistor R3 is arranged between the voltage division resistor R2 and the second grounding terminal, and the voltage sampling point V1 is arranged between the voltage division resistor R2 and the voltage division resistor R3.

[0010] Further, the resistance value of the voltage division resistor R3 is more than 100 times that of the voltage division resistor R2.

[0011] Further, the resistance value of the voltage division resistor R3 is greater than 10 KΩ.

[0012] The present invention also discloses a high-voltage interlock signal detection method using the above high-voltage interlock signal detection system, including:

[0013] Turn on the reference power supply; detect the voltage value of the voltage sampling point V1; diagnose the circuit connection state of the external circuit according to the voltage value of the voltage sampling point V1 and the calculated voltage value range.

[0014] Further, the circuit connection states of the external circuit include five states: normal closed, open circuit fault, short to ground fault, short to power supply fault, and other faults. The diagnosis unit calculates voltage value ranges corresponding one by one to the five states according to the circuit connection relationship of the detection system. When the voltage value of the detected voltage sampling point V1 falls within one of the voltage value ranges, it is diagnosed that the external circuit is in the circuit connection state corresponding to the voltage value range. Among them, the other faults refer to circuit faults that occur in the external circuit other than open circuit faults, short to ground faults, and short to power supply faults.

[0015] Further, the diagnosis unit diagnoses in sequence according to the five states of normal closed, open circuit fault, short to ground fault, short to power supply fault, and other faults. If it is diagnosed that the external circuit is in one of the four fault states other than normal closed, the diagnosis ends; otherwise, the next round of diagnosis continues.

[0016] Further, the voltage dividing unit includes a voltage dividing resistor R2 and a voltage dividing resistor R3. One end of the voltage dividing resistor R3 is grounded, and the other end is connected to the voltage dividing resistor R2. The input end of the diagnosis unit is connected to the voltage sampling point V1 provided between the voltage dividing resistor R2 and the voltage dividing resistor R3.

[0017] After adopting the above technical solutions, compared with the prior art, the following beneficial effects are achieved:

[0018] 1. Fewer circuit components are used, saving economic costs;

[0019] 2. Only the voltage of one point is sampled, introducing less sampling error;

[0020] 3. The diagnosis scheme is simple. The circuit is diagnosed directly according to the voltage value of the voltage sampling point V1, occupying less resources of the MCU. Description of the Drawings

[0021] Figure 1 It is a circuit schematic diagram of a high-voltage interlock signal detection system in the prior art;

[0022] Figure 2 It is a circuit schematic diagram of a high-voltage interlock signal detection system conforming to the present invention;

[0023] Figure 3 It is a flowchart of a high-voltage interlock signal detection method conforming to the present invention.

[0024] Reference Numerals:

[0025] 1 - reference power supply, 2 - voltage dividing and diagnosis module, 3 - constant current source. Detailed Embodiments

[0026] The advantages of the present invention will be further elaborated below in conjunction with the accompanying drawings and specific embodiments.

[0027] Here, exemplary embodiments will be described in detail, and examples thereof are shown in the drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. On the contrary, they are merely examples of devices consistent with some aspects of the present disclosure as detailed in the appended claims.

[0028] The terms used in the present disclosure are for the purpose of describing specific embodiments only and are not intended to limit the present disclosure. The singular forms "a", "the", and "said" used in the present disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0029] It should be understood that although the terms first, second, third, etc. may be used in the present disclosure to describe various information, such information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other.

[0030] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0031] In the description of the present invention, unless otherwise specified and defined, it should be noted that the terms "mounted", "connected", and "connected" should be understood in a broad sense. For example, it may be a mechanical connection or an electrical connection, or it may be the communication of the inner cavities of two elements. It may be directly connected, or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0032] The present invention provides a high-voltage interlock signal detection system. Refer to Figure 2, the high-voltage interlock signal detection system includes: a reference power supply 1, a voltage division diagnosis module 2, a constant current source 3, and an external circuit SEG; the voltage division diagnosis module 2 includes a current limiting unit, a voltage division unit, a diagnosis unit, and a diagnosis resistor R4. The output terminal of the reference power supply 1 is connected to the input terminal of the current limiting unit. From the output terminal of the current limiting unit to the first ground terminal GND1, the external circuit SEG and the constant current source 3 are connected in sequence. From the output terminal of the current limiting unit to the second ground terminal GND2, the voltage division unit is connected; wherein, the external circuit SEG is connected in parallel with the diagnosis resistor R4. The input terminal of the diagnosis unit is connected to the voltage sampling point V1 of the voltage division unit. The diagnosis unit is used to detect the voltage value of the voltage sampling point V1 and diagnose the circuit connection state of the external circuit SEG according to the voltage value of the voltage sampling point V1 and the calculated voltage value range.

[0033] Wherein, the external circuit SEG is a circuit formed by connecting high-voltage devices in series.

[0034] Preferably, in this embodiment, as Figure 2 shown, the diagnosis unit is an MCU. The current limiting unit is a resistor R1, and its function is to perform series voltage division when a short-circuit power supply fault occurs in the external circuit SEG, thereby limiting the loop current to protect the circuit.

[0035] The voltage division unit includes a voltage division resistor R2 and a voltage division resistor R3. The voltage division resistor R3 is arranged between the voltage division resistor R2 and the second ground terminal. The voltage sampling point V1 is arranged between the voltage division resistor R2 and the voltage division resistor R3. Therefore, in this embodiment, the voltage value across the voltage division resistor R3 is the voltage value of the voltage sampling point V1.

[0036] Preferably, in this embodiment, the circuit connection states of the external circuit SEG include five states: normal closed, open circuit fault, short to ground fault, short circuit power supply fault, and other faults. The diagnosis unit is used to calculate the voltage value ranges corresponding to the five states one by one. When the detected voltage value of V1 falls within a voltage value range, it is diagnosed that the external circuit is in the circuit connection state corresponding to the voltage value range; wherein, the other fault refers to a circuit fault that occurs in the external circuit other than the open circuit fault, short to ground fault, and short circuit power supply fault.

[0037] Specifically, referring to Figure 2 , according to the series-parallel relationship of the circuit and combining Ohm's law, equations 1 and 2 can be obtained. Among them, equation 1:

[0038]

[0039] Equation 2:

[0040]

[0041] From Equation 1 and Equation 2, Equation 3 can be obtained:

[0042]

[0043] Among them, V REF is the output voltage of the reference power supply 1, and V2 is the voltage value of the voltage sampling point V2. is the parallel equivalent resistance of the external loop SEG and the diagnostic resistor R4, and R5 is the equivalent resistance of the constant current source 3.

[0044] In this embodiment, V REF = 5V, R1 = 205Ω, R2 = 1KΩ, R3 = 100KΩ, R4 = 500Ω; R5 is the equivalent resistance of the constant current source. When the current limiting function is not activated, the equivalent resistance value is about 95Ω.

[0045] State 1:

[0046] When the external loop SEG is normally closed, that is, there is no fault, the theoretical value of the resistance of the external loop SEG is 0Ω, but the resistance of each connection wire in the actual circuit is not 0. Therefore, the equivalent resistance value of the external loop SEG is set to Ra. Substituting into Equation 3 and adding the redundancy amount a set by the system, the first voltage value range of the sampling point V1 can be calculated. When the resistance value of the power supply sampling point V1 is detected within the first voltage value range, it is diagnosed that the circuit connection state of the external loop SEG is normally closed.

[0047] It should be understood that those of ordinary skill in the art can determine the value of Ra according to the actual situation of the high-voltage interlock signal detection system, generally in the range of 0 to 10Ω. In this embodiment, Ra is taken as 9Ω. The redundancy amount a is set by those of ordinary skill in the art according to the actual needs of the system. In this embodiment, the redundancy amount a is set to 1V.

[0048] In this embodiment, the calculated first voltage value range is [1.5V, 2.5V].

[0049] State 2:

[0050] When an open circuit fault occurs in the external loop SEG, the equivalent resistance value of the external loop SEG is 10KΩ (10KΩ is a conventional industry experience value in this field). Substituting into Equation 3 and adding the redundancy amount a set by the system, the second voltage value range of the sampling point V1 can be calculated. When the voltage value of the voltage sampling point V1 is detected within the second voltage value range, it is diagnosed that the circuit connection state of the external loop SEG is an open circuit fault.

[0051] In this embodiment, the calculated second voltage value range is [3.0V, 4.0V].

[0052] State 3:

[0053] When a short - circuit - to - ground fault occurs in the external circuit SEG, Figure 2 the voltage at point A is almost 0V. At this time, the voltage at point V2 is equal to the voltage at point A. Substituting into Equation 2, it can be obtained that V1 is approximately 0V. Adding the redundancy amount a set in the system, the third voltage value range of the sampling point V1 can be calculated. When the voltage value of the voltage sampling point V1 is detected within the third voltage value range, it is diagnosed that the circuit connection state of the external circuit SEG is a short - circuit - to - ground fault.

[0054] In this embodiment, the calculated third voltage value range is [0, 1V).

[0055] State 4:

[0056] When a short - circuit - to - power - supply fault occurs in the external circuit SEG, that is, the external circuit SEG is short - circuited to the loop power supply it is connected to. At this time, Figure 2 the voltage value at point V2 is equal to the voltage of the loop power supply of the external circuit SEG. The high - voltage interlock signal detection system of this embodiment is applied to the battery management module of a new - energy vehicle. The loop power supply connected to the external circuit SEG is the low - voltage battery on the new - energy vehicle, usually 12V. Substituting into Equation 2 and adding the redundancy amount a set in the system, the fourth voltage value range of the sampling point V1 can be calculated. When the voltage value of the voltage sampling point V1 is detected within the fourth voltage value range, it is diagnosed that the circuit connection state of the external circuit SEG is a short - circuit - to - power - supply fault.

[0057] In this embodiment, the calculated fourth voltage value range is >= 4.5V.

[0058] State 5:

[0059] When the voltage value of the voltage sampling point V1 is not within the first voltage value range, the second voltage value range, the third voltage value range, and the fourth voltage value range, it is diagnosed that the circuit connection state of the external circuit SEG is other faults. The other faults refer to circuit faults that occur in the external circuit SEG other than open - circuit faults, short - circuit - to - ground faults, and short - circuit - to - power - supply faults.

[0060] According to the above five voltage value ranges, the correspondence table between the voltage value V1 of the voltage sampling point V1 and the circuit connection state of the external circuit in this embodiment is as follows:

[0061]

[0062] Preferably, refer to Figure 3, the diagnosis unit is used to sequentially diagnose the external loop in the order of five states: normal closed, open - circuit fault, short - to - ground fault, short - to - power - supply fault, and other faults. If it is diagnosed that the external loop SEG is in one of the four fault states other than normal closed, the diagnosis ends; otherwise, the next round of diagnosis continues.

[0063] Preferably, the resistance value of the voltage - dividing resistor R3 is 100 times or more than 100 times that of the voltage - dividing resistor R2. Among them, more preferably, R3>10 kΩ. In this embodiment, the voltage - dividing resistor R3 is a single resistor with a resistance value of 100 KΩ. In other embodiments, the voltage - dividing resistor R3 can be split into small resistors in series or large resistors in parallel.

[0064] It should be understood that the larger the ratio of the voltage - dividing resistor R3 to the voltage - dividing resistor R2, the closer the voltage value at point V1 is to that at point V2, and the closer the voltage value at point V1 is to that at point V2, the better the sampling accuracy.

[0065] The present invention also provides a high - voltage interlock signal detection method applying the above - mentioned high - voltage interlock signal detection system, including:

[0066] Turn on the reference power supply 1,

[0067] The output end of the reference power supply 1 is connected to the input end of the current - limiting unit. From the output end of the current - limiting unit to the first ground terminal GND1, the external loop SEG and the constant - current source 3 are connected in sequence. From the output end of the current - limiting unit to the second ground terminal GND2, the voltage - dividing unit is connected; among them, the external loop SEG is connected in parallel with the diagnostic resistor R4, and the input end of the diagnosis unit is connected to the voltage sampling point V1 of the voltage - dividing unit.

[0068] Detect the voltage value of the voltage sampling point V1,

[0069] The voltage value of the voltage sampling point V1 is detected through the diagnosis unit. In this embodiment, the diagnosis unit is an MCU, and the input end of the MCU collects the voltage signal of the voltage sampling point V1 of the voltage - dividing unit to obtain the voltage value of the voltage sampling point V1 of the voltage - dividing unit.

[0070] Diagnose the circuit connection state of the external loop according to the voltage value of the voltage sampling point V1 and the calculated voltage value range.

[0071] Preferably, the circuit connection states of the external circuit SEG include five states: normal closed, open circuit fault, short to ground fault, short power supply fault, and other faults. The diagnosis unit calculates voltage value ranges corresponding to the five states one by one according to the circuit connection relationship of the detection system. When the voltage value of the detected voltage sampling point V1 falls within one of the voltage value ranges, it is diagnosed that the external circuit SEG is in the circuit connection state corresponding to the voltage value range. Among them, the other fault refers to a circuit fault that occurs in the external circuit other than the open circuit fault, short to ground fault, and short power supply fault.

[0072] It should be understood that the calculation process of the voltage value ranges corresponding to the five states has been described in detail in the above embodiments of the high-voltage interlock signal detection system and will not be repeated here.

[0073] Preferably, referring to Figure 3 , the diagnosis unit diagnoses in sequence according to the five states of normal closed, open circuit fault, short to ground fault, short power supply fault, and other faults. If it is diagnosed that the external circuit SEG is in one of the four fault states other than normal closed, the diagnosis ends; otherwise, the next round of diagnosis continues.

[0074] Preferably, referring to Figure 2 , the voltage dividing unit includes a voltage dividing resistor R2 and a voltage dividing resistor R3. One end of the voltage dividing resistor R3 is grounded, and the other end is connected to the voltage dividing resistor R2. The input end of the diagnosis unit is connected to the voltage sampling point V1 provided between the voltage dividing resistor R2 and the voltage dividing resistor R3.

[0075] Preferably, the resistance value of the voltage dividing resistor R3 is 100 times or more than 100 times that of the voltage dividing resistor R2. Among them, more preferably, R3 > 10 kΩ. In this embodiment, the voltage dividing resistor R3 is a single resistor with a resistance value of 100 KΩ. In other embodiments, the voltage dividing resistor R3 can be split into small resistors in series or large resistors in parallel.

[0076] It should be understood that the larger the ratio of the voltage dividing resistor R3 to the voltage dividing resistor R2, the closer the voltage value at point V1 is to the voltage value at point V2, and the closer the voltage value at point V1 is to the voltage value at point V2, the better the sampling accuracy.

[0077] Referring to Figure 1, which shows the circuit schematic diagram of the high-voltage interlock signal detection system in the prior art. This solution has a complex circuit, many resistors, and a high economic cost; there are many sampling points, resulting in a relatively large voltage sampling error, and the errors introduced in subsequent resistance and current calculations will also increase accordingly; the diagnostic solution is complex and prone to misjudgment. In addition, multiple resistance and current calculations are required, resulting in a high resource occupancy rate of the single-chip microcomputer. By using the high-voltage interlock signal detection system and method provided by the present invention, on the one hand, fewer circuit components are used, saving economic costs; on the other hand, only the voltage at one point is sampled, introducing a smaller sampling error, and the diagnostic solution is simple, directly diagnosing the circuit based on the voltage value of the voltage sampling point V1, occupying fewer resources of the MCU.

[0078] It should be noted that the embodiments of the present invention have better implementability and are not in any form a limitation to the present invention. Any person skilled in the art may use the disclosed technical content to modify or decorate it into equivalent effective embodiments. However, as long as it does not depart from the technical content of the technical solution of the present invention, any modification, equivalent change, or decoration made to the above embodiments according to the technical essence of the present invention still falls within the scope of the technical solution of the present invention.

Claims

1. A high-voltage interlock signal detection system, characterized in that Comprising: A reference power supply, a voltage division diagnosis module, a constant current source, and an external circuit; The voltage division diagnosis module includes a current limiting unit, a voltage division unit, a diagnosis unit, and a diagnosis resistor; The output end of the reference power supply is connected to the input end of the current limiting unit. The external circuit and the constant current source are sequentially connected from the output end of the current limiting unit to the first ground terminal, and the voltage division unit is connected from the output end of the current limiting unit to the second ground terminal; Wherein, the external circuit is connected in parallel with the diagnosis resistor. The input end of the diagnosis unit is connected to the voltage sampling point V1 of the voltage division unit. The diagnosis unit is used to detect the voltage value of the voltage sampling point V1, and diagnose the circuit connection state of the external circuit according to the voltage value of the voltage sampling point V1 and the calculated voltage value range.

2. The high-voltage interlock signal detection system according to claim 1, wherein The circuit connection state of the external circuit includes five states: normal closed, open circuit fault, short to ground fault, short to power supply fault, and other faults. The diagnosis unit is used to calculate the voltage value range corresponding to the five states one by one according to the circuit connection relationship of the detection system. When the detected voltage value of the voltage sampling point V1 falls within a voltage value range, it is diagnosed that the external circuit is in the circuit connection state corresponding to the voltage value range; Wherein, the other fault refers to a circuit fault of the external circuit other than the open circuit fault, short to ground fault, and short to power supply fault.

3. The high-voltage interlock signal detection system according to claim 2, wherein The diagnosis unit is used to sequentially diagnose the external circuit in the order of five states: normal closed, open circuit fault, short to ground fault, short to power supply fault, and other faults. If it is diagnosed that the external circuit is in one of the four fault states other than normal closed, the diagnosis is ended; otherwise, the next round of diagnosis is continued.

4. The high-voltage interlock signal detection system according to claim 1, wherein The voltage division unit includes a voltage division resistor R2 and a voltage division resistor R3. The voltage division resistor R3 is arranged between the voltage division resistor R2 and the second ground terminal, and the voltage sampling point V1 is arranged between the voltage division resistor R2 and the voltage division resistor R3.

5. The high-voltage interlock signal detection system according to claim 4, wherein The resistance value of the voltage division resistor R3 is more than 100 times that of the voltage division resistor R2.

6. The high-voltage interlock signal detection system according to claim 5, wherein The resistance value of the voltage division resistor R3 is greater than 10 KΩ.

7. A high-voltage interlock signal detection method for applying the high-voltage interlock signal detection system as described in claim 1, characterized in that, Comprising: Turn on the reference power supply; Detect the voltage value of the voltage sampling point V1; Diagnose the circuit connection state of the external circuit according to the voltage value of the voltage sampling point V1 and the calculated voltage value range.

8. The high-voltage interlock signal detection method according to claim 7, wherein The circuit connection states of the external circuit include five states: normal closed, open circuit fault, short to ground fault, short to power supply fault, and other faults. The diagnosis unit calculates voltage value ranges corresponding one by one to the five states according to the circuit connection relationship of the detection system. When the voltage value of the detected voltage sampling point V1 falls within one of the voltage value ranges, it is diagnosed that the external circuit is in the circuit connection state corresponding to this voltage value range; Among them, the other fault refers to a circuit fault that occurs in the external circuit other than the open circuit fault, short to ground fault, and short to power supply fault.

9. The high-voltage interlock signal detection method according to claim 8, wherein The diagnosis unit diagnoses in sequence according to the five states of normal closed, open circuit fault, short to ground fault, short to power supply fault, and other faults. If it is diagnosed that the external circuit is in one of the four fault states other than normal closed, the diagnosis ends; otherwise, the next round of diagnosis continues.

10. The high-voltage interlock signal detection method according to claim 9, wherein The voltage dividing unit includes a voltage dividing resistor R2 and a voltage dividing resistor R3. One end of the voltage dividing resistor R3 is grounded, and the other end is connected to the voltage dividing resistor R2. The input end of the diagnosis unit is connected to the voltage sampling point V1 provided between the voltage dividing resistor R2 and the voltage dividing resistor R3.

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