High-Voltage Interlock Circuit and Detection Method for Connectors in Vehicle High-Voltage Circuits

Abstract

An embodiment of the present invention discloses a high-voltage interlock circuit and a detection method for a connector in a vehicle high-voltage circuit. The high-voltage interlock circuit includes: a switch circuit, a voltage-dividing circuit, and at least one detection branch; the detection branch includes a first input terminal, a second input terminal, a third input terminal, and a first detection terminal; the first input terminal of the detection branch is connected to a first power supply V1, the second input terminal of the detection branch 30 is grounded, and the third input terminal of the detection branch is connected to a connector in the vehicle high-voltage circuit; the first end of the switch circuit is connected to the third input terminal of the detection branch through the voltage-dividing circuit, the second end of the switch circuit 20 is grounded, and the control end of the switch circuit is connected to a PWM signal; the switch circuit is turned on or off according to the PWM signal. Through the technical solution of this embodiment, the stability of the detection signal output by the high-voltage interlock circuit is improved, and the accuracy of the high-voltage interlock circuit for detecting the connection state of the connector is improved.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of new energy electric vehicles, and in particular, to a high-voltage interlock circuit and a method for detecting a connector in a vehicle high-voltage circuit loop. Background Art

[0002] In new energy electric vehicles, a high-voltage interlock (HVIL) circuit is used to detect the connection state of high-voltage connectors in the vehicle high-voltage circuit loop and identify faults such as unconnected or accidentally disconnected high-voltage connectors.

[0003] During the operation of the high-voltage interlock circuit, the vehicle battery management system provides a PWM signal to the high-voltage interlock circuit through the pins of its own control board. However, when the power supply voltage for providing the PWM signal is low, the received PWM signal by the high-voltage interlock circuit is not obvious and difficult to identify, resulting in an unclear detection signal output by the high-voltage interlock circuit and inaccurate detection results for the connection state of the connector; when the power supply voltage for providing the PWM signal is high, it is easy to burn out the pins of the control board of the vehicle battery management system; when the power supply voltage for providing the PWM signal jitters or fluctuates, it will also affect the PWM signal fluctuation, and similarly, the detection results of the high-voltage interlock circuit for the connection state of the connector are inaccurate. Summary of the Invention

[0004] The embodiments of the present invention provide a high-voltage interlock circuit and a method for detecting a connector in a vehicle high-voltage circuit loop, which improve the stability of the detection signal output by the high-voltage interlock circuit and the accuracy of detecting the connection state of the connector by the high-voltage interlock circuit.

[0005] In a first aspect, the embodiments of the present invention provide a high-voltage interlock circuit, which includes: a switch circuit, a voltage-dividing circuit, and at least one detection branch;

[0006] The detection branch includes a first input terminal, a second input terminal, a third input terminal, and a first detection terminal; the first input terminal of the detection branch is connected to a first power supply, the second input terminal of the detection branch is grounded, and the third input terminal of the detection branch is connected to a connector in the vehicle high-voltage circuit loop;

[0007] The first end of the switch circuit is connected to the third input terminal of the detection branch through the voltage-dividing circuit, the second end of the switch circuit is grounded, and the control end of the switch circuit is connected to a PWM signal; the switch circuit conducts or turns off according to the PWM signal.

[0008] Optionally, the high-voltage interlock circuit includes a first detection branch, a second detection branch, and a third detection branch;

[0009] The first input terminal of the first detection branch, the first input terminal of the second detection branch, and the first input terminal of the third detection branch are all connected to the first power supply;

[0010] The second input terminal of the first detection branch, the second input terminal of the second detection branch, and the second input terminal of the third detection branch are all grounded;

[0011] The third input terminal of the first detection branch is connected to the first connector branch, the third input terminal of the second detection branch is connected to the second connector branch, and the third input terminal of the third detection branch is connected to the third connector branch;

[0012] The third input terminals of the first detection branch, the second detection branch, and the third detection branch are all connected to the first end of the switch circuit through the voltage dividing circuit, and the voltage dividing circuit changes the voltage division of the first detection branch, the second detection branch, and the third detection branch according to the conduction or cutoff of the switch circuit.

[0013] Optionally, the voltage dividing circuit includes a first impedance unit;

[0014] The first end of the first impedance unit is connected to the first end of the switch circuit, and the second end of the first impedance unit is connected to the third input terminal of the detection branch.

[0015] Optionally, the switch circuit includes a triode;

[0016] The first pole of the triode serves as the first end of the switch circuit, the second pole of the triode serves as the second end of the switch circuit, and the control end of the triode serves as the control end of the switch circuit.

[0017] Optionally, the detection branch includes a second impedance unit, a third impedance unit, and a fourth impedance unit;

[0018] The first end of the second impedance unit serves as the first input terminal of the detection branch, and the second end of the second impedance unit serves as the third input terminal of the detection branch;

[0019] The first end of the third impedance unit is connected to the second end of the second impedance unit, and the second end of the third impedance unit serves as the first detection end of the detection circuit;

[0020] The first end of the fourth impedance unit is connected to the second end of the third impedance unit, and the second end of the fourth impedance unit serves as the second input terminal of the detection circuit.

[0021] Optionally, the voltage dividing circuit includes a first impedance unit, the first impedance unit includes a first resistor, the second impedance unit includes a second resistor, the third impedance unit includes a third resistor, and the fourth impedance unit includes a fourth resistor; wherein, the resistance value of the first resistor is less than the resistance value of any one of the second resistor, the third resistor, and the fourth resistor.

[0022] Optionally, a total detection branch is further included;

[0023] The total detection branch includes a first input end, a second input end, a second detection end, a fifth impedance unit, and a sixth impedance unit;

[0024] The first input end of the total detection branch is connected to the third input end of each detection branch, and the second input end of the total detection branch is grounded;

[0025] The first end of the fifth impedance unit serves as the first input end of the total detection branch, and the second end of the fifth impedance unit serves as the second detection end of the total detection branch;

[0026] The first end of the sixth impedance unit is connected to the second end of the fifth impedance unit, and the second end of the sixth impedance unit serves as the second input end of the total detection branch.

[0027] In a second aspect, an embodiment of the present invention further provides a method for detecting a connector in a vehicle high-voltage circuit. The method is executed by the high-voltage interlock circuit described in the first aspect above. The method includes:

[0028] Providing a PWM signal to the control end of the switch circuit;

[0029] Receiving a detection signal from the first detection end of the detection branch;

[0030] If the detection signal is a PWM signal, it is determined that the connection state of the connector in the vehicle high-voltage circuit is normal; if the detection signal is a constant level signal, it is determined that the connection state of the connector in the vehicle high-voltage circuit is faulty.

[0031] Optionally, the high-voltage interlock circuit includes a first detection branch, a second detection branch, and a third detection branch;

[0032] If the detection signal received from the first detection end of the first detection branch is a PWM signal, it is determined that the connection state of the first connector branch is normal; if the detection signal received from the first detection end of the first detection branch is a constant level signal, it is determined that the connection state of the first connector branch is faulty;

[0033] If the detection signal received from the first detection end of the second detection branch is a PWM signal, it is determined that the connection state of the first connector branch is normal; if the detection signal received from the first detection end of the second detection branch is a constant level signal, it is determined that the connection state of the second connector branch is faulty.

[0034] Optionally, the high-voltage interlock circuit further includes a detection main branch, and the detection main branch includes a second detection end:

[0035] The method further includes receiving a detection signal from the second detection end;

[0036] If the detection signals received from the first detection end are all high-level signals and the detection signal received from the second detection end is a PWM signal, it is determined that the connection states of the first connector branch, the second connector branch, and the third connector branch are all open circuits;

[0037] If the detection signals received from the first detection end and the detection signals received from the second detection end are all low-level signals, it is determined that the connection states of the first connector branch, the second connector branch, and the third connector branch are all short-circuited to ground;

[0038] If the detection signals received from the first detection end and the detection signals received from the second detection end are all high-level signals, it is determined that the connection states of the first connector branch, the second connector branch, and the third connector branch are all short-circuited to the power supply;

[0039] If the detection signals received from the first detection end are all high-level signals and the detection signal received from the second detection end is a low-level signal, it is determined that the connection states of the first connector branch, the second connector branch, and the third connection branch are all open circuits, and the detection main branch is short-circuited to ground.

[0040] The high-voltage interlock circuit provided by the embodiment of the present invention, wherein the third input end of the detection branch is connected to a connector in the vehicle high-voltage circuit. By setting a switching circuit and a voltage-dividing circuit, when the switching circuit conducts or turns off according to the PWM signal received at the self-control end, the voltage-dividing circuit changes the voltage division of the detection branch. For example, when the switching circuit conducts according to the PWM signal, the voltage-dividing circuit divides the voltage of the detection branch, and when the switching circuit turns off according to the PWM signal, the voltage-dividing circuit does not divide the voltage of the detection branch. Thus, a PWM signal with an obvious level signal can be detected at the first detection end of the detection branch, that is, the PWM signal detected from the first detection end is more obvious than the PWM signal received by the switching circuit, and the difference between the high and low levels of the PWM signal detected from the first detection end is larger than the difference between the high and low levels of the PWM signal received by the switching circuit. It can also be understood that the PWM signal received by the switching circuit is enhanced at the first detection end through the switching circuit and the voltage-dividing circuit. In this way, the connection state of the connector in the high-voltage circuit can be judged according to the obvious or enhanced PWM signal received from the first detection end. The obvious PWM signal is easy to identify, which improves the accuracy of the high-voltage interlock circuit in detecting the connection state of the connector, and avoids the problem that when the power supply voltage of the provided PWM signal is low, the PWM signal received by the high-voltage interlock circuit is not obvious and not easy to identify, resulting in an inaccurate detection result due to the unobvious detection signal received from the first detection end. At the same time, the stability of the enhanced PWM signal is better, which improves the stability of the detection signal output from the first detection end and avoids the problem that the accuracy of the detection result is easily affected when the power supply voltage of the provided PWM signal jitters or fluctuates. In addition, it also avoids burning out the pins of the vehicle battery management system control board by providing a high power supply voltage to provide an obvious PWM signal to the high-voltage interlock circuit, ensuring the safety of the vehicle battery management system. Description of the Drawings

[0041] Figure 1 is a schematic structural diagram of a high-voltage interlock circuit provided by an embodiment of the present invention;

[0042] Figure 2 is a schematic diagram of the connection relationship of multiple connectors in a vehicle high-voltage circuit provided by an embodiment of the present invention;

[0043] Figure 3 is a schematic structural diagram of another high-voltage interlock circuit provided by an embodiment of the present invention;

[0044] Figure 4 is a schematic structural diagram of another high-voltage interlock circuit provided by an embodiment of the present invention;

[0045] Figure 5 is a schematic structural diagram of another high-voltage interlock circuit provided by an embodiment of the present invention;

[0046] Figure 6 It is a schematic structural diagram of another high-voltage interlock circuit provided by an embodiment of the present invention;

[0047] Figure 7 It is a schematic structural diagram of another high-voltage interlock circuit provided by an embodiment of the present invention;

[0048] Figure 8 It is a schematic flow diagram of a method for detecting a connector in a vehicle high-voltage circuit provided by an embodiment of the present invention. Detailed implementation manners

[0049] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present invention, rather than limiting the present invention. In addition, it should be noted that for the sake of description, only parts related to the present invention rather than all structures are shown in the drawings.

[0050] Figure 1 It is a schematic structural diagram of a high-voltage interlock circuit provided by an embodiment of the present invention. Refer to Figure 1 , the high-voltage interlock circuit includes: a switch circuit 20, a voltage-dividing circuit 10, and at least one detection branch 30; the detection branch 30 includes a first input end, a second input end, a third input end, and a first detection end A; the first input end of the detection branch 30 is connected to a first power supply V1, the second input end of the detection branch 30 is grounded, and the third input end of the detection branch 30 is connected to a connector in the vehicle high-voltage circuit; the first end of the switch circuit 20 is connected to the third input end of the detection branch 30 through the voltage-dividing circuit 10, the second end of the switch circuit 20 is grounded, and the control end of the switch circuit 20 is connected to a PWM signal; the switch circuit 20 is turned on or off according to the PWM signal.

[0051] In this embodiment, the high-voltage interlock circuit can be connected in a vehicle battery management system (Battery Management System, BMS). It can be the BMS that provides the first power supply V1 and the PWM signal to the high-voltage interlock circuit, that is, the first input end of the detection branch 30 and the control end of the switch circuit 20 are respectively connected to different pins of the BMS control board. The voltage magnitude of the first power supply V1 can be +12 volts. The switch circuit 20 can be a circuit including one or more transistors. The BMS can also provide a second power supply V2 to the high-voltage interlock circuit through a resistor R7. The voltage magnitude of the second power supply V2 can be +12 volts to improve the reliability of the high-voltage interlock circuit.

[0052] The third input terminal of the detection branch 30 is connected to a connector in the vehicle high-voltage circuit to establish a connection with the connector in the vehicle high-voltage circuit. One or more connectors in the vehicle high-voltage circuit may be connected in series in each detection branch 30. The voltage-dividing circuit 10 may be a circuit including one or more impedance elements. When the voltage-dividing circuit 10 is connected to the detection branch 30 (that is, when the voltage-dividing circuit 10 establishes an electrical connection relationship with the detection branch 30), the voltage-dividing circuit 10 can divide the voltage of the detection branch 30. When the voltage-dividing circuit 10 is not connected to the detection branch 30 (that is, when the voltage-dividing circuit 10 disconnects the electrical connection relationship with the detection branch 30), the voltage-dividing circuit 10 does not divide the voltage of the detection branch 30. The first detection terminal A of the detection branch 30 is the port for the high-voltage interlock circuit to output the detection signal. It can be that the BMS analyzes and judges the connection state of the connector according to the detection signal. Therefore, the first detection terminal A can be connected to the pin of the BMS control board so that the BMS can obtain the detection signal from the first detection terminal A.

[0053] Based on this, referring to Figure 1 , Figure 1 only one detection branch 30 is schematically shown exemplarily. The high-voltage interlock circuit provided in this embodiment may also include multiple detection branches 30. The working principle of the high-voltage interlock circuit provided in this embodiment may be: The PWM signal includes high and low level signals. When the PWM signal is input to the control terminal of the switch circuit 20, the switch circuit 20 conducts or turns off in response to the high and low level signals of the PWM signal. For example, the switch circuit 20 conducts in response to the high level signal of the PWM signal and turns off in response to the low level signal of the PWM signal. As Figure 1 can be seen, when the switch circuit 20 conducts, the voltage-dividing circuit 10 establishes an electrical connection relationship with the detection branch 30, so that the voltage-dividing circuit 10 divides the voltage of the detection branch 30; when the switch circuit 20 turns off, the voltage-dividing circuit 10 disconnects the connection relationship with the detection branch 30, so that the voltage-dividing circuit 10 does not divide the voltage of the detection branch 30.

[0054] In this way, the switching circuit 20 continuously conducts, turns off, conducts, turns off... according to the PWM signal, causing the voltage dividing circuit 10 to change the voltage division of the detection branch 30, that is, continuously dividing the voltage of the detection branch 30, not dividing the voltage, dividing the voltage, not dividing the voltage... As a result, a distinct PWM signal can be received at the first detection end A of the detection branch 30. That is, compared with the prior art where the PWM signal is simply directly input into the HVIL circuit to output a detection signal for characterizing the connection state of the connector, in the high-voltage interlock circuit provided in this embodiment, by setting the switching circuit 20 and the voltage dividing circuit 10, the PWM signal detected from the first detection end A is more distinct than the PWM signal received by the switching circuit 20, that is, more distinct than the PWM signal directly input into the high-voltage interlock circuit. In other words, the difference between the high and low levels of the PWM signal detected from the first detection end A is greater than the difference between the high and low levels of the PWM signal received by the switching circuit 20. It can also be understood that the PWM signal received by the switching circuit 20 is enhanced at the first detection end A through the switching circuit 20 and the voltage dividing circuit 10.

[0055] Accordingly, the connection state of the connector in the high-voltage circuit can be determined based on the distinct or enhanced PWM signal received from the first detection end A. The distinct PWM signal is easy to identify, improving the accuracy of the high-voltage interlock circuit in detecting the connection state of the connector, and avoiding the problem that when the power supply voltage providing the PWM signal is low, the PWM signal received by the high-voltage interlock circuit is not distinct and difficult to identify, resulting in an indistinct detection signal received from the first detection end A and inaccurate detection results. At the same time, the enhanced PWM signal has better stability, improving the stability of the detection signal output from the first detection end A and avoiding the problem that the accuracy of the detection result is easily affected when the power supply voltage providing the PWM signal jitters or fluctuates. In addition, it also avoids burning out the pins of the vehicle battery management system control board by providing a high power supply voltage to provide a distinct PWM signal to the high-voltage interlock circuit, ensuring the safety of the vehicle battery management system.

[0056] Exemplarily, the BMS can determine that the connection state of the connector corresponding to the detection branch 30 is normal based on the PWM wave received from the first detection end A, and determine that the connection state of the connector corresponding to the detection branch 30 is faulty based on the constant level signal received from the first detection end A; for example, if the first detection end A always outputs a PWM wave within a certain detection time, it is determined that the connection state of the connector corresponding to the detection branch 30 is normal, and at this time, the high voltage on the vehicle can be controlled to enter the operating state. If the first detection end A always outputs a high-level signal or a low-level signal within a certain detection time, it is determined that the connection state of the connector corresponding to the detection branch 30 is faulty, and at this time, the vehicle can be controlled not to go on high voltage and the connector can be repaired and then go on high voltage.

[0057] Figure 2 It is a schematic diagram of the connection relationship of multiple connectors in the high-voltage circuit of a vehicle provided by an embodiment of the present invention. Figure 3 It is a schematic diagram of the structure of another high-voltage interlock circuit provided by the present invention. In combination with Figure 2 and Figure 3 , optionally, the high-voltage interlock circuit includes a first detection branch 301, a second detection branch 302, and a third detection branch 303;

[0058] The first input end of the first detection branch 301, the first input end of the second detection branch 302, and the first input end of the third detection branch 303 are all connected to a first power supply V1;

[0059] The second input end of the first detection branch 301, the second input end of the second detection branch 302, and the second input end of the third detection branch 303 are all grounded;

[0060] The third input end of the first detection branch 301 is connected to a first connector branch, the third input end of the second detection branch 302 is connected to a second connector branch, and the third input end of the third detection branch 303 is connected to a third connector branch;

[0061] The third input end of the first detection branch 301, the third input end of the second detection branch 302, and the third input end of the third detection branch 303 are all connected to the first end of the switch circuit 20 through the voltage dividing circuit 10, and the voltage dividing circuit 10 changes the voltage division for the first detection branch 301, the second detection branch 302, and the third detection branch 303 according to the conduction or cutoff of the switch circuit 20.

[0062] Specifically, referring to Figure 2 , the connectors in the high-voltage circuit of the vehicle include but are not limited to a DC / DC module 3110, a fast charging connector 3111, a slow charging connector 3112, a PACK connector 3220, a high-voltage box connector 3221, a relay 3222, an electrode drive connector 3330, an air conditioner connector 3331, etc. Among them, multiple connectors are connected in series to form a branch, and specifically which connectors are connected in series to form a branch can be determined by the actual circuit layout. In addition, as Figure 2 shown schematically in, each connector is connected to the BMS 50, and the BMS supplies power to each connector. Figure 2 The first detection end A is shown on the BMS in

[0063] to indicate that the high-voltage interlock circuit provided in this embodiment can be integrated on the BMS control board. Figure 2 In combination with Figure 3, in this embodiment, three connector branches (i.e., 311, 322, 333) are correspondingly provided with three detection branches 30 (i.e., 301, 302, 303) in the high-voltage interlock circuit. Each connector branch is correspondingly connected to the corresponding detection branch 30 (for example, connector branch 311 is connected to detection branch 301 through the third input terminal of detection branch 301, connector branch 322 is connected to detection branch 302 through the third input terminal of detection branch 302, and connector branch 333 is connected to detection branch 303 through the third input terminal of detection branch 303), that is, each detection branch 30 correspondingly detects the connection state of the connector branch connected thereto.

[0064] Exemplarily, the detection signal output by the first detection end A of the first detection branch 301 can be used to judge the connection state of the first connector branch, the detection signal output by the first detection end A of the second detection branch 302 can be used to judge the connection state of the second connector branch, and the detection signal output by the first detection end A of the third detection branch 303 can be used to judge the connection state of the third connector branch. For example, for the first detection branch 301, if the first detection end A of the first detection branch 301 always outputs a PWM wave within a certain detection time, it is determined that the connection state with the first connector branch is normal, and if the first detection end A of the first detection branch 301 always outputs a high-level signal or a low-level signal within a certain detection time, it is determined that the connection state with the first connector branch is faulty.

[0065] In this embodiment, multiple connectors in the vehicle high-voltage circuit are connected in series to form a branch, and correspondingly, a corresponding detection branch is provided in the high-voltage interlock circuit, that is, all the connectors in the vehicle high-voltage circuit are divided into several connector branches, and then multiple detection branches are correspondingly provided to respectively detect the connection state of each connector branch. This avoids the technical problems of too large a range of fault detection caused by using a single detection branch to detect all the connectors in the vehicle high-voltage circuit and inaccurate fault location of the connectors in the vehicle high-voltage circuit resulting in a large amount of maintenance work.

[0066] Figure 4 is a schematic structural diagram of another high-voltage interlock circuit provided by an embodiment of the present invention. Refer to Figure 4 , optionally, the voltage-dividing circuit 10 includes a first impedance unit L1; the first end of the first impedance unit L1 is connected to the first end of the switch circuit 20, and the second end of the first impedance unit L1 is connected to the third input terminal of the detection branch 30.

[0067] Specifically, the main function of the voltage dividing circuit 10 is to divide the voltage of the detection branch 30 when the detection branch 30 is connected. The first impedance unit L1 may include one or more impedance elements, such as resistor elements, etc. The one or more impedance elements may be in series and / or in parallel, which is not limited herein. The impedance of the first impedance unit L1 is preferably much smaller than the impedance of the detection branch 30. The smaller the impedance of the first impedance unit L1 is compared with the impedance of the detection branch 30, the more obvious the contrast between the detection branch 30 being voltage-divided by the voltage dividing circuit 10 and not being voltage-divided is. Thus, the high and low level signals detected by the first detection end A are more obvious. Furthermore, the higher the accuracy of the high-voltage interlock circuit for detecting the connection state of the connector is, and the stronger the stability of the high and low level signals detected by the first detection end A is.

[0068] Continue to refer to Figure 4 , optionally, the switch circuit 20 includes a triode Q; the first pole of the triode Q serves as the first end of the switch circuit 20, the second pole of the triode Q serves as the second end of the switch circuit 20, and the control end of the triode Q serves as the control end of the switch circuit 20.

[0069] Specifically, Figure 4 exemplarily shows that the triode is an NPN type triode. The triode in the switch circuit 20 may also be a PNP type triode or other switching transistors, which is not limited herein. As Figure 4 shown, the triode Q conducts in response to the high level signal of the PWM signal (the triode Q is in the amplification state). Correspondingly, when the connection state of the connector (or the connector branch) is normal, the first detection end A of the detection branch 30 can detect a high level signal; the triode Q turns off in response to the low level signal of the PWM signal (the triode Q is in the cut-off state). Correspondingly, when the connection state of the connector (or the connector branch) is normal, the first detection end A of the detection branch 30 can detect a low level signal; and when the connection state of the connector (or the connector branch) fails, even if the triode keeps conducting and turning off within a certain detection time, the first detection end A always outputs a high level signal or a low level signal.

[0070] Figure 5 is a schematic structural diagram of another high-voltage interlock circuit provided by an embodiment of the present invention. Refer to Figure 5 , optionally, the detection branch 30 includes a second impedance unit L2, a third impedance unit L3, and a fourth impedance unit L4;

[0071] The first end of the second impedance unit L2 serves as the first input end of the detection branch 30, and the second end of the second impedance unit L2 serves as the third input end of the detection branch 30;

[0072] The first end of the third impedance unit L3 is connected to the second end of the second impedance unit L2, and the second end of the third impedance unit L3 serves as the first detection end A of the detection circuit;

[0073] The first end of the fourth impedance unit L4 is connected to the second end of the third impedance unit L3, and the second end of the fourth impedance unit L4 serves as the second input end of the detection circuit.

[0074] Specifically, the second impedance unit L2, the third impedance unit L3, and the fourth impedance unit L4 may each include one or more impedance elements, such as resistance elements, etc. The one or more impedance elements may be in series and / or in parallel, which is not limited herein.

[0075] Reference Figure 5 , the working principle of the high-voltage interlock circuit provided in this embodiment is further described: The second impedance unit L2 plays a protective role in the high-voltage interlock circuit to ensure the reliability of the high-voltage interlock circuit. When the PWM signal is input to the base of the triode, the triode conducts or cuts off in response to the high and low level signals of the PWM signal. For example, it conducts in response to the high-level signal of the PWM signal and cuts off in response to the low-level signal of the PWM signal.

[0076] When the triode is cut off, the first impedance unit L1 is not connected in parallel to the third impedance unit L3 and the fourth impedance unit L4. The total resistance of the detection branch 30 is the total resistance of the second impedance unit L2, the third impedance unit L3, and the fourth impedance unit L4, and the voltage dividing circuit 10 does not divide the voltage of the detection branch 30; when the triode is conducting, the first impedance unit L1 is connected in parallel to the third impedance unit L3 and the fourth impedance unit L4. The total resistance of the detection branch 30 is the total resistance of the first impedance unit L1, the second impedance unit L2, the third impedance unit L3, and the fourth impedance unit L4. That is, due to the incorporation of the first impedance unit L1, the total resistance of the detection branch 30 is reduced, and the voltage dividing circuit 10 realizes the voltage division of the detection branch 30. In this way, since the triode conducts or cuts off in response to the PWM signal, correspondingly, the voltage dividing circuit 10 realizes the voltage division or non-voltage division of the detection branch 30, that is, the first impedance unit L1 is connected in parallel or not connected in parallel to the second impedance unit L2, the third impedance unit L3, and the fourth impedance unit L4, so that the resistance of the detection branch 30 is larger or smaller, and thus an obvious level signal (i.e., the detection signal) can be detected at the first detection end A, and then the connection state of the connector (or the connector branch) can be accurately judged according to the obvious detection signal.

[0077] Figure 6 is a schematic structural diagram of another high-voltage interlock circuit provided by an embodiment of the present invention. Reference Figure 6, optionally, the first impedance unit L1 includes a first resistor R1, the second impedance unit L2 includes a second resistor R2, the third impedance unit L3 includes a third resistor R3, and the fourth impedance unit L4 includes a fourth resistor R4; wherein, the resistance value of the first resistor R1 is less than the resistance value of any one of the second resistor R2, the third resistor R3, and the fourth resistor R4.

[0078] Specifically, the seventh resistor R7 can protect the high-voltage interlock circuit. The resistance value of the seventh resistor R7, the resistance value of the second resistor R2, and the resistance value of the fourth resistor R4 can be set to be equal for easy calculation. At the same time, the resistance value of the third resistor R3 can be set to twice the resistance value of the fourth resistor R4, and the resistance value of the first resistor R1 is much less than the resistance value of the fourth resistor R4; for example, the resistance value of the fourth resistor R4 is 10 kΩ and the resistance value of the first resistor R1 is a few hundred ohms. The smaller the resistance value of the first resistor R1 is compared to the fourth resistor R4, the more obvious the contrast between the divided voltage and the non-divided voltage of the detection branch 30 by the voltage dividing circuit 10, so that the high and low level signals detected by the first detection end A are more obvious. Furthermore, the higher the accuracy of the high-voltage interlock circuit in detecting the connection state of the connector, and the stronger the stability of the high and low level signals detected by the first detection end A.

[0079] Figure 7 is a schematic structural diagram of another high-voltage interlock circuit provided by an embodiment of the present invention. Refer to Figure 7 , the high-voltage interlock circuit provided in this embodiment further includes a detection main branch 40; the detection main branch 40 includes a first input end, a second input end, a second detection end B, a fifth impedance unit L5, and a sixth impedance unit L6; the first input end of the detection main branch 40 is connected to the third input ends of the respective detection branches 30, and the second input end of the detection main branch 40 is grounded; the first end of the fifth impedance unit L5 serves as the first input end of the detection main branch 40, and the second end of the fifth impedance unit L5 serves as the second detection end B of the detection main branch 40; the first end of the sixth impedance unit L6 is connected to the second end of the fifth impedance unit L5, and the second end of the sixth impedance unit L6 serves as the second input end of the detection main branch 40.

[0080] Specifically, both the fifth impedance unit L5 and the sixth impedance unit L6 can include one or more impedance elements, such as resistor elements, etc. The one or more impedance elements can be in series and / or in parallel, which is not limited herein. Optionally, the fifth impedance unit L5 can include a fifth resistor R5, and the sixth impedance unit L6 can include a sixth resistor R6. The resistance values of the fifth resistor R5 and the sixth resistor R6 can both be equal to or close to the resistance value of the second resistor R2.

[0081] When there are multiple detection branches 30 in the high-voltage interlock circuit, setting a detection main branch 40 can detect the connection state of a large loop 3 formed by the multiple detection branches 30, and the connection state of the loop 3 can be determined according to the detection signal received by the second detection end B. Exemplarily, during the process that the switch circuit 20 continuously conducts and turns off according to the PWM signal received by its control end:

[0082] If it is detected that all the detection signals output by the first detection end A are high-level signals within the detection time, and the detection signal output by the second detection end B is a PWM wave, then the BMS determines that the loop 3 is open; if it is detected that all the detection signals output by the first detection end A and the detection signal output by the second detection end B are low-level signals within the detection time, then the BMS determines that the loop 3 is short-circuited to the ground; if it is detected that all the detection signals output by the first detection end A and the detection signal output by the second detection end B are high-level signals within the detection time, then the BMS determines that the loop 3 is short-circuited to the power supply; if it is detected that all the detection signals output by the first detection end A are high-level signals, and the detection signal output by the second detection end B is a low-level signal within the detection time, then the BMS determines that the loop 3 is open and the first input end C point of the total detection branch 30 is short-circuited to the ground.

[0083] The embodiment of the present invention also provides a method for detecting a connector in a vehicle high-voltage loop, and the method is executed by the high-voltage interlock circuit described in any of the above technical solutions. Figure 8 It is a schematic flowchart of a method for detecting a connector in a vehicle high-voltage loop provided by an embodiment of the present invention. As Figure 8 shown and combined with Figure 2 and Figure 6 , the method for detecting a connector in a vehicle high-voltage loop includes:

[0084] S10, providing a PWM signal to the control end of the switch circuit. Specifically, the BMS 50 can provide a PWM signal to the control end of the switch circuit 20.

[0085] S20, receiving a detection signal from the first detection end of the detection branch. Specifically, the pin of the BMS 50 can be connected to the first detection end A, so as to receive the detection signal from the first detection end A, and the detection signal includes a PWM wave or a constant level signal.

[0086] S30. If the detected signal is a PWM signal, it is determined that the connection state of the connector in the vehicle high-voltage circuit is normal; if the detected signal is a constant level signal, it is determined that the connection state of the connector in the vehicle high-voltage circuit is faulty. Specifically, if the BMS 50 determines that the detected signal output from the first detection terminal A within the detection time is a PWM wave, it is determined that the connection state of the connector (or connector branch) in the vehicle high-voltage circuit connected to the current detection branch 30 is normal; if the BMS 50 determines that the detected signal output from the first detection terminal A within the detection time is a constant level signal, for example, a constant high-level signal, it is determined that the connection state of the connector (or connector branch) in the vehicle high-voltage circuit connected to the current detection branch 30 is faulty.

[0087] The detection method of the connector in the vehicle high-voltage circuit provided in this embodiment and the high-voltage interlock circuit described in any of the above technical solutions belong to the same inventive concept and can achieve the same technical effects. The repeated content will not be elaborated here.

[0088] Optionally, in combination with Figure 2 and Figure 6 , the high-voltage interlock circuit includes a first detection branch 301, a second detection branch 302, and a third detection branch 303; the connector branch 311 is connected to the detection branch 301 through the third input terminal of the detection branch 301, the connector branch 322 is connected to the detection branch 302 through the third input terminal of the detection branch 302, and the connector branch 333 is connected to the detection branch 303 through the third input terminal of the detection branch 303; step S30 includes:

[0089] If the detected signal received from the first detection terminal A of the first detection branch 301 is a PWM signal, it is determined that the connection state of the first connector branch 311 is normal; if the detected signal received from the first detection terminal A of the first detection branch 301 is a constant level signal, it is determined that the connection state of the first connector branch 311 is faulty;

[0090] If the detected signal received from the first detection terminal A of the second detection branch 302 is a PWM signal, it is determined that the connection state of the first connector branch 311 is normal; if the detected signal received from the first detection terminal A of the second detection branch 302 is a constant level signal, it is determined that the connection state of the second connector branch 322 is faulty.

[0091] Specifically, when simultaneously detecting the first connector branch 311, the second connector branch 322, and the third connector branch 333, within the detection time:

[0092] If the detection signals received at the first detection end A of the first detection branch 301, the first detection end A of the second detection branch 302, and the first detection end A of the third detection branch 303 are all PWM waves, it is determined that there is no fault in the connector in the vehicle high-voltage circuit, and based on this, the vehicle can be controlled to enter the high-voltage operating state;

[0093] If the detection signal received at the first detection end A of the first detection branch 301 is a constant high-level signal, and the detection signals received at the first detection end A of the second detection branch 302 and the first detection end A of the third detection branch 303 are both PWM waves, it is determined that the fault location of the connector in the vehicle high-voltage circuit is in the first connector branch 311;

[0094] If the detection signal received at the first detection end A of the first detection branch 301 is a PWM wave, the detection signal received at the first detection end A of the second detection branch 302 is a constant high-level signal, and the detection signal received at the first detection end A of the third detection branch 303 is a PWM wave, it is determined that the fault location of the connector in the vehicle high-voltage circuit is in the second connector branch 322;

[0095] If the detection signal received at the first detection end A of the first detection branch 301 is a PWM wave, the detection signal received at the first detection end A of the second detection branch 302 is a PWM wave, and the detection signal received at the first detection end A of the third detection branch 303 is a constant high-level signal, it is determined that the fault location of the connector in the vehicle high-voltage circuit is in the third connector branch 333;

[0096] If the detection signals received at the first detection end A of the first detection branch 301 and the first detection end A of the second detection branch 302 are both constant high-level signals, and the detection signal received at the first detection end A of the third detection branch 303 is a PWM wave, it is determined that the fault location of the connector in the vehicle high-voltage circuit is in the first connector branch 311 and the second connector branch 322;

[0097] If the detection signal received at the first detection end A of the first detection branch 301 is a PWM wave, the detection signal received at the first detection end A of the second detection branch 302 is a constant high-level signal, and the detection signal received at the first detection end A of the third detection branch 303 is a constant high-level signal, it is determined that the fault location of the connector in the vehicle high-voltage circuit is in the second connector branch 322 and the third connector branch 333;

[0098] If the detection signal received at the first detection end A of the first detection branch 301 is a constant high-level signal, the detection signal received at the first detection end A of the second detection branch 302 is a PWM wave, and the detection signal received at the first detection end A of the third detection branch 303 is a constant high-level signal, it is determined that the fault location of the connector in the vehicle high-voltage circuit is located in the first connector branch 311 and the third connector branch 333.

[0099] Here, for the above detection results, if the setting of the total detection branch 40 is considered, in each detection result, a PWM wave is output at the second detection end B of the total detection branch 40.

[0100] Optionally, in combination with Figure 2 and Figure 6 , the high-voltage interlock circuit further includes a total detection branch 40, and the total detection branch 40 includes a second detection end B; the first input end of the total detection branch 40 is connected to the third input ends of the respective detection branches 30, and the second input end of the total detection branch 40 is grounded; the detection method for the connector in the vehicle high-voltage circuit further includes step S40 of receiving a detection signal from the second detection end B; step 30 includes:

[0101] If the detection signals received from the first detection end A are all high-level signals, and the detection signal received from the second detection end B is a PWM signal, it is determined that the connection states of the first connector branch 311, the second connector branch 322, and the third connector branch 333 are all open circuits;

[0102] If the detection signals received from the first detection end A and the detection signal received from the second detection end B are both low-level signals, it is determined that the connection states of the first connector branch 311, the second connector branch 322, and the third connector branch 333 are all short-circuited to the ground;

[0103] If the detection signals received from the first detection end A and the detection signal received from the second detection end B are both high-level signals, it is determined that the connection states of the first connector branch 311, the second connector branch 322, and the third connector branch 333 are all short-circuited to the power supply;

[0104] If the detection signals received from the first detection end A are all high-level signals, and the detection signal received from the second detection end B is a low-level signal, it is determined that the connection states of the first connector branch 311, the second connector branch 322, and the third connection branch are all open circuits, and the total detection branch 40 is short-circuited to the ground.

[0105] Specifically, when the total detection branch 40, the first connector branch 311, the second connector branch 322, and the third connector branch 333 are detected simultaneously, within the detection time:

[0106] If the detection signal received at the second detection end B of the self-detection main branch 40 is a PWM wave, and the detection signals received at the first detection end A of the first detection branch 301, the first detection end A of the second detection branch 302, and the first detection end A of the third detection branch 303 are all constant high-level signals, it is determined that the faults of the connectors in the vehicle high-voltage circuit are that the first connector branch 311, the second connector branch 322, and the third connector branch 333 are all open circuits, that is, circuit 3 is open;

[0107] If the detection signal received at the second detection end B of the self-detection main branch 40 is a constant low-level signal, and the detection signals received at the first detection end A of the first detection branch 301, the first detection end A of the second detection branch 302, and the first detection end A of the third detection branch 303 are all constant low-level signals, it is determined that the faults of the connectors in the vehicle high-voltage circuit are that the first connector branch 311, the second connector branch 322, and the third connector branch 333 are all short-circuited to the ground, that is, circuit 3 is short-circuited to the ground;

[0108] If the detection signal received at the second detection end B of the self-detection main branch 40 is a constant high-level signal, and the detection signals received at the first detection end A of the first detection branch 301, the first detection end A of the second detection branch 302, and the first detection end A of the third detection branch 303 are all constant high-level signals, it is determined that the faults of the connectors in the vehicle high-voltage circuit are that the first connector branch 311, the second connector branch 322, and the third connector branch 333 are all short-circuited to the power supply, that is, circuit 3 is short-circuited to the power supply;

[0109] If the detection signal received at the second detection end B of the self-detection main branch 40 is a constant low-level signal, and the detection signals received at the first detection end A of the first detection branch 301, the first detection end A of the second detection branch 302, and the first detection end A of the third detection branch 303 are all constant high-level signals, it is determined that the faults of the connectors in the vehicle high-voltage circuit are that the first connector branch 311, the second connector branch 322, and the third connector branch 333 are all open circuits, that is, circuit 3 is open, and the first input end C point of the self-detection main branch 40 is short-circuited to the ground.

[0110] In summary, the detection method of the connector in the vehicle high-voltage circuit provided in this embodiment and the high-voltage interlock circuit described in any of the above technical solutions can not only improve the accuracy of the high-voltage interlock circuit in detecting the connection state of the connector, and avoid the problem that when the power supply voltage of the PWM signal is low, the PWM signal received by the high-voltage interlock circuit is not obvious and difficult to identify, so that the detection signal received from the first detection end is not obvious and the detection result is inaccurate. At the same time, it improves the stability of the detection signal output by the first detection end and avoids the problem that the accuracy of the detection result is easily affected when the power supply voltage of the PWM signal jitters or fluctuates. In addition, it also avoids burning out the pins of the vehicle battery management system control board by providing a high power supply voltage to provide an obvious PWM signal to the high-voltage interlock circuit, ensuring the safety of the vehicle battery management system. Besides the beneficial effects, it can also judge the fault types of the connectors in the vehicle high-voltage circuit, for example, judge which connector branches are faulty, and judge the open circuit, short circuit to ground and short circuit to power supply of the connector branches.

[0111] Note that the above is only the preferred embodiment of the present invention and the technical principles applied. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described here. Various obvious changes, re-adjustments and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments only. Without departing from the concept of the present invention, it can also include more other equivalent embodiments, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A high-voltage interlock circuit, characterized in that, Including: A switching circuit, a voltage dividing circuit, and at least one detection branch; The detection branch includes a first input terminal, a second input terminal, a third input terminal, and a first detection terminal; the first input terminal of the detection branch is connected to a first power supply, the second input terminal of the detection branch is grounded, and the third input terminal of the detection branch is connected to a connector in the vehicle high-voltage circuit; The first end of the switching circuit is connected to the third input terminal of the detection branch through the voltage dividing circuit, the second end of the switching circuit is grounded, and the control end of the switching circuit is connected to a PWM signal; the switching circuit is turned on or off according to the PWM signal; wherein, the switching circuit includes a triode; The high-voltage interlock circuit further includes a detection main branch; The detection main branch includes a first input terminal, a second input terminal, a second detection terminal, a fifth impedance unit, and a sixth impedance unit; The first input terminal of the detection main branch is connected to the third input terminal of each detection branch, and the second input terminal of the detection main branch is grounded; The first end of the fifth impedance unit serves as the first input terminal of the detection main branch, and the second end of the fifth impedance unit serves as the second detection terminal of the detection main branch; The first end of the sixth impedance unit is connected to the second end of the fifth impedance unit, and the second end of the sixth impedance unit serves as the second input terminal of the detection main branch; Wherein, during the process of the switching circuit being turned on and off according to the PWM signal received by the control end: if it is detected that all the detection signals output by the first detection terminals are high-level signals within the detection time, and the detection signal output by the second detection terminal is a PWM wave, it is determined that the loop formed by multiple detection branches is open; if it is detected that all the detection signals output by the first detection terminals and the detection signals output by the second detection terminal are low-level signals within the detection time, it is determined that the loop formed by multiple detection branches is short-circuited to the ground; if it is detected that all the detection signals output by the first detection terminals and the detection signals output by the second detection terminal are high-level signals within the detection time, it is determined that the loop formed by multiple detection branches is short-circuited to the power supply; if it is detected that all the detection signals output by the first detection terminals are high-level signals, and the detection signal output by the second detection terminal is a low-level signal within the detection time, it is determined that the loop formed by multiple detection branches is open and the detection main branch is short-circuited to the ground; The detection branch includes a second impedance unit, a third impedance unit, and a fourth impedance unit; The first end of the second impedance unit serves as the first input terminal of the detection branch, and the second end of the second impedance unit serves as the third input terminal of the detection branch; The first end of the third impedance unit is connected to the second end of the second impedance unit, and the second end of the third impedance unit serves as the first detection terminal of the detection branch; The first end of the fourth impedance unit is connected to the second end of the third impedance unit, and the second end of the fourth impedance unit serves as the second input terminal of the detection branch; The voltage dividing circuit includes a first impedance unit, the first impedance unit includes a first resistor, the second impedance unit includes a second resistor, the third impedance unit includes a third resistor, and the fourth impedance unit includes a fourth resistor; wherein, the resistance value of the first resistor is less than the resistance value of any one of the second resistor, the third resistor, and the fourth resistor, so that the PWM signal received by the switch circuit is enhanced at the first detection end through the switch circuit and the voltage dividing circuit.

2. The high-voltage interlock circuit according to claim 1, wherein The high-voltage interlock circuit includes a first detection branch, a second detection branch, and a third detection branch; The first input ends of the first detection branch, the second detection branch, and the third detection branch are all connected to the first power supply; The second input ends of the first detection branch, the second detection branch, and the third detection branch are all grounded; The third input end of the first detection branch is connected to the first connector branch, the third input end of the second detection branch is connected to the second connector branch, and the third input end of the third detection branch is connected to the third connector branch; The third input ends of the first detection branch, the second detection branch, and the third detection branch are all connected to the first end of the switch circuit through the voltage dividing circuit, and the voltage dividing circuit changes the voltage division of the first detection branch, the second detection branch, and the third detection branch according to the conduction or cutoff of the switch circuit.

3. The high-voltage interlock circuit according to claim 1, wherein The voltage dividing circuit includes a first impedance unit; The first end of the first impedance unit is connected to the first end of the switch circuit, and the second end of the first impedance unit is connected to the third input end of the detection branch.

4. The high-voltage interlock circuit according to claim 1, wherein The first pole of the triode serves as the first end of the switch circuit, the second pole of the triode serves as the second end of the switch circuit, and the control end of the triode serves as the control end of the switch circuit.

5. A detection method for a connector in a vehicle high-voltage circuit, characterized in that, Performed by the high-voltage interlock circuit according to any one of claims 1-4, the method includes: Providing a PWM signal to the control end of the switch circuit; Receiving a detection signal from the first detection end of the detection branch; If the detection signal is a PWM signal, it is determined that the connection state of the connector in the vehicle high-voltage loop is normal; if the detection signal is a constant level signal, it is determined that the connection state of the connector in the vehicle high-voltage loop is faulty.

6. The detection method of a connector in a vehicle high-voltage circuit according to claim 5, wherein, The high-voltage interlock circuit includes a first detection branch, a second detection branch, and a third detection branch; If the detection signal received from the first detection end of the first detection branch is a PWM signal, it is determined that the connection state of the first connector branch is normal; If the detection signal received from the first detection end of the first detection branch is a constant level signal, it is determined that the connection state of the first connector branch is faulty; If the detection signal received from the first detection end of the second detection branch is a PWM signal, it is determined that the connection state of the second connector branch is normal; If the detection signal received from the first detection end of the second detection branch is a constant level signal, it is determined that there is a connection state failure in the second connector branch.

7. The detection method of a connector in a vehicle high-voltage circuit according to claim 6, characterized in that, The high-voltage interlock circuit further includes a detection main branch, and the detection main branch includes a second detection end: The method further includes receiving a detection signal from the second detection end; If the detection signals received from the first detection end are all high-level signals and the detection signal received from the second detection end is a PWM signal, it is determined that the connection states of the first connector branch, the second connector branch, and the third connector branch are all open circuits; If the detection signals received from the first detection end and the detection signal received from the second detection end are both low-level signals, it is determined that the connection states of the first connector branch, the second connector branch, and the third connector branch are all short-circuited to the ground; If the detection signals received from the first detection end and the detection signal received from the second detection end are both high-level signals, it is determined that the connection states of the first connector branch, the second connector branch, and the third connector branch are all short-circuited to the power supply; If the detection signals received from the first detection end are all high-level signals and the detection signal received from the second detection end is a low-level signal, it is determined that the connection states of the first connector branch, the second connector branch, and the third connector branch are all open circuits, and the detection main branch is short-circuited to the ground.

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