High voltage interlock detection circuit

Abstract

The application relates to a high-voltage interlocking detection circuit. The high-voltage interlocking detection circuit comprises a constant current source, a first voltage detection module and a resistance module. The first end of the first voltage detection module is connected to the output end of the constant current source; the first ends of the resistance module are respectively connected to the second end of the first voltage detection module and the first end of a high-voltage interlocking module, and the second end of the resistance module is connected to the second end of the high-voltage interlocking module; wherein the third end of the first voltage detection module is used for outputting a first voltage signal, and the first voltage signal is used for representing the on-off state of the high-voltage interlocking module. The circuit can realize the detection of the on-off state of the high-voltage interlocking module and the resistance of the high-voltage interlocking module, and significantly reduces the complexity and design cost of the high-voltage interlocking detection circuit.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electronic circuits, and in particular to a high-voltage interlock detection circuit. BACKGROUND

[0002] In a new energy vehicle, a high-voltage interlock (HVIL) circuit is used to ensure the safe connection of high-voltage system components. In the related art, many HVIL circuits use a pulse width modulation (PWM) signal to detect the circuit state. However, the above-mentioned technology not only increases the system cost and design complexity, but also has limited detection functions.

[0003] Therefore, it is an urgent need in the industry to develop a simpler, lower-cost HVIL circuit that can provide more comprehensive fault detection capabilities. SUMMARY

[0004] Therefore, it is necessary to provide a high-voltage interlock detection circuit.

[0005] In a first aspect, the present application provides a high-voltage interlock detection circuit, which comprises:

[0006] a constant current source;

[0007] a first voltage detection module, a first end of the first voltage detection module being connected to an output end of the constant current source;

[0008] a resistance module, first ends of the resistance module being respectively connected to a second end of the first voltage detection module and a first end of a high-voltage interlock module, and a second end of the resistance module being connected to a second end of the high-voltage interlock module;

[0009] wherein a third end of the first voltage detection module is configured to output a first voltage signal, and the first voltage signal is configured to represent an on-off state of the high-voltage interlock module.

[0010] In one embodiment, the first voltage detection module comprises:

[0011] a first voltage dividing unit, a first end of the first voltage dividing unit being connected to the output end of the constant current source, and second ends of the first voltage dividing unit being respectively connected to the first ends of the resistance module and the high-voltage interlock module;

[0012] a first sampling unit, a first end of the first sampling unit being connected to the first end of the first voltage dividing unit, and a second end of the first sampling unit being configured to output the first voltage signal.

[0013] In one embodiment, the first sampling unit comprises:

[0014] a first sampling resistor, a first end of the first sampling resistor being connected to the first end of the resistance module;

[0015] A second sampling resistor, a first end of the second sampling resistor is connected to a second end of the first sampling resistor, and the first end of the second sampling resistor is configured to output the first voltage signal.

[0016] In one of the embodiments, the high-voltage interlock detection circuit further comprises:

[0017] A second voltage detection module, a first end of the second voltage detection module is connected to the second end of the resistance module and the second end of the high-voltage interlock module respectively, and a second end of the second voltage detection module is configured to output a second voltage signal, the second voltage signal is configured to represent a working state of the high-voltage interlock detection circuit.

[0018] In one of the embodiments, the second voltage detection module comprises:

[0019] A second voltage dividing unit, a first end of the second voltage dividing unit is connected to the second end of the resistance module and the second end of the high-voltage interlock module respectively;

[0020] A second sampling unit, a first end of the second sampling unit is connected to the first end of the second voltage dividing unit, and a second end of the second sampling unit is configured to output the second voltage signal.

[0021] In one of the embodiments, the second voltage dividing unit comprises:

[0022] A plurality of voltage dividing resistors, the voltage dividing resistors are connected to the second end of the resistance module and the second end of the high-voltage interlock module, and the first end of the second sampling unit respectively.

[0023] In one of the embodiments, the plurality of voltage dividing resistors have equal resistance values, and the high-voltage interlock detection circuit further comprises:

[0024] A switching unit, a first end of the switching unit is configured to access a control signal, and a second end of the switching unit is connected to a second end of the second voltage dividing unit;

[0025] A replacement resistor, a first end of the replacement resistor is connected to a third end of the switching unit, a second end of the replacement resistor is connected to the second end of the resistance module and the first end of the second sampling unit respectively, and the replacement resistor has equal resistance values with the voltage dividing resistors.

[0026] In one of the embodiments, the high-voltage interlock detection circuit further comprises:

[0027] A control module, the control module is connected to the third end of the first voltage detection module, and the control module is configured to determine a conduction state of the high-voltage interlock module according to the first voltage signal.

[0028] And / or,

[0029] The control module is configured to determine a resistance value of the high-voltage interlock module according to the first voltage signal in the conduction state when it is determined that the high-voltage interlock module is in the conduction state.

[0030] In one of the embodiments, the high-voltage interlock detection circuit further comprises:

[0031] a control module, the control module being connected with the third end of the first voltage detection module and the second end of the second voltage detection module respectively, and the control module being configured to determine the fault condition of the first voltage detection module and the second voltage detection module according to the first voltage signal and the second voltage signal when the high-voltage interlock module is in the on state.

[0032] In one of the embodiments, the high-voltage interlock detection circuit further comprises:

[0033] a control module, the control module being configured to determine that the first end of the second voltage detection module is faulty when the first voltage signal when the switch unit is connected with the control signal is equal to the first reference signal and the second voltage signal when the switch unit is connected with the control signal is equal to the second reference signal when the high-voltage interlock module is in the on state.

[0034] The first reference signal is the first voltage signal when the high-voltage interlock detection circuit is not faulty and the high-voltage interlock module is in the on state, and the second reference signal is the second voltage signal when the high-voltage interlock detection circuit is not faulty and the high-voltage interlock module is in the on state.

[0035] The high-voltage interlock detection circuit has at least the following beneficial effects:

[0036] By using the constant current source, the first voltage detection module and the resistance module, the complexity of the high-voltage interlock detection circuit is significantly reduced. The circuit does not use an operational amplifier and an integrated IC for generating a PWM signal, only a small amount of MCU port resources are occupied, the circuit design is simplified, and the design cost is greatly reduced. More importantly, the circuit can not only accurately determine the on-off state of the high-voltage interlock module, but also identify the resistance value of the external total resistance by detecting the voltage value of the first voltage signal combined with the known resistance value, so as to detect whether the high-voltage interlock module has a poor contact or an increased contact resistance, find potential problems in advance, and prevent the high-voltage interlock from failing. BRIEF DESCRIPTION OF DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort.

[0038] Figure 1 is one of the structural schematic diagrams of the high-voltage interlock detection circuit in one of the embodiments;

[0039] Figure 2 Fig. 2 is a schematic diagram of a high-voltage interlock detection circuit according to an embodiment of the present application;

[0040] Figure 3 Fig. 3 is a schematic diagram of a high-voltage interlock detection circuit according to an embodiment of the present application;

[0041] Figure 4 Fig. 4 is a schematic diagram of a high-voltage interlock detection circuit according to an embodiment of the present application;

[0042] Figure 5 Fig. 5 is a schematic diagram of a high-voltage interlock detection circuit according to an embodiment of the present application;

[0043] Figure 6 Fig. 6 is a schematic diagram of a high-voltage interlock detection circuit according to an embodiment of the present application. DETAILED DESCRIPTION

[0044] In order to facilitate the understanding of the present application, the present application will be described in more detail below with reference to the relevant drawings. The drawings show embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terminology used in the specification of the present application is only for the purpose of describing specific embodiments and is not intended to limit the present application.

[0046] It can be understood that the terms "first", "second", and the like used in the present application can be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish the first element from another element. For example, without departing from the scope of the present application, the first resistor can be referred to as the second resistor, and similarly, the second resistor can be referred to as the first resistor. The first resistor and the second resistor are both resistors, but they are not the same resistor.

[0047] It can be understood that "connection" in the following embodiments, if the circuits, modules, modules, etc. connected to each other have the transmission of electrical signals or data, should be understood as "electrically connected", "communicatively connected", etc.

[0048] It can be understood that "at least one" means one or more, and "multiple" means two or more. "At least part of the element" means part or all of the element.

[0049] As used herein, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. It will be further understood that the terms "comprises", "comprising", "includes" and / or "including", or the like, when used in this specification, specify the presence of stated features, integers, steps, operations, modules, parts or the like, but do not preclude the presence or addition of one or more other features, integers, steps, operations, modules, parts or the like. Also, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0050] With the rapid development of new energy vehicle technology, the safety of high-voltage electrical system has become one of the key factors in vehicle design. As an important mechanism to ensure the safe operation of high-voltage system, the reliability of high-voltage interlock (HVIL) directly affects the safety performance of the whole vehicle. In the existing high-voltage interlock detection circuit, using pulse width modulation (PWM) waveform signal for state monitoring is a relatively common method. However, this method has the following limitations: First, the design of PWM generator usually depends on dedicated integrated IC chip, which not only increases the cost of the circuit, but also increases the design complexity. Second, in order to realize effective monitoring of the PWM signal, it is necessary to set up amplitude sampling and frequency sampling circuits at the output and input ends of the HVIL, which undoubtedly increases the hardware requirements of the system and also occupies more microcontroller unit (MCU) resources. In addition, due to the relatively complex PWM signal detection logic, high-frequency sampling of the input and output PWM signals and comparison of level changes are required, which not only increases the operation burden of the MCU, but also may lead to misjudgment due to insufficient sampling accuracy. More importantly, the existing PWM signal detection method can only determine whether the HVIL is in the on or off state, and cannot timely discover the possible contact failure and increased contact resistance of external connecting parts, thus it is difficult to prevent possible system failure problems in advance.

[0051] Based on the above reasons, in one exemplary embodiment, as Figure 1As shown, the application provides a high-voltage interlock detection circuit, which comprises a constant current source 2, a first voltage detection module 4 and a resistance module 6. The first end of the first voltage detection module 4 is connected to the output end of the constant current source 2; the first end of the resistance module 6 is connected to the second end of the first voltage detection module 4 and the first end of the high-voltage interlock module 700 respectively, and the second end of the resistance module 6 is connected to the second end of the high-voltage interlock module 700; wherein the third end of the first voltage detection module 4 is used to output a first voltage signal, and the first voltage signal is used to represent the on-off state of the high-voltage interlock module 700.

[0052] Wherein, the constant current source 2 can refer to a power supply device capable of outputting a fixed current, no matter how the load changes, the constant current source 2 can maintain the stability of the output current. The function of the constant current source 2 is to provide a stable current reference for the high-voltage interlock detection circuit, so that when the state of the high-voltage interlock module 700 changes (i.e. from on to off or from off to on), the voltage change generated by the resistance module 6 can be accurately captured by the first voltage detection module 4, so as to realize accurate monitoring of the state of the high-voltage interlock module 700. In the automotive electronic system, a line that is always live (such as KL30) can be connected to the positive electrode of the small battery of the vehicle, so that the system basis chip (SBC) in the electronic control unit (ECU) can also provide stable power supply in the vehicle sleep or wake-up state. The SBC can convert the power received from the KL30 into stable voltages required by each part inside the ECU, such as 12V, 5V, etc. Among them, the 5V power supply can be used to power the constant current source 2, so that the constant current source 2 outputs a constant current (such as 10mA). The high-voltage interlock module 700 includes various types of high-voltage connectors, such as BMS high-voltage connectors, electric drive high-voltage connectors, OBC high-voltage connectors, DC-DC high-voltage connectors, air conditioning high-voltage connectors, etc. Each high-voltage connector includes a connector female head, a connector male head and an intermediate interlock terminal in the connector female head and the connector male head, and by connecting the intermediate interlock terminals in each high-voltage connector in series, the above-mentioned high-voltage interlock module 700 is formed.

[0053] Exemplarily, the constant current output by the constant current source 2, when passing through the first voltage detection module 4 and the resistance module 6, will generate different voltage drops at the first end of the first voltage detection module 4 and the first end of the resistance module 6 respectively based on the resistance of the first voltage detection module 4 and the resistance module 6 themselves. Since the middle interlocking terminals of each high-voltage connector in the high-voltage interlocking module 700 have very small resistance, the middle interlocking terminals can be regarded as wires when they are connected in series. Based on this, when the high-voltage interlocking module 700 is in the on state, the resistance module 6 is equivalent to being short-circuited by a wire, and the voltage drop at the first end of the first voltage detection module 4 is the product of the resistance of the first voltage detection module 4 itself and the constant current, at which time the voltage value of the first voltage signal output is lower; when the high-voltage interlocking module 700 is in the off state, the resistance module 6 is not short-circuited by a wire, and the voltage drop at the first end of the first voltage detection module 4 is the product of the resistance of the first voltage detection module 4 and the resistance module 6 themselves and the constant current, at which time the voltage value of the first voltage signal output is higher. Therefore, the control module such as MCU can obtain the voltage drop at the first end of the first voltage detection module 4 based on the first voltage signal output by the first voltage detection module 4, so as to determine the on state of the high-voltage interlocking module 700. In addition, during the selection and design of the circuit, the resistance value of the resistance module 6 and the resistance value of the first voltage detection module 4 are usually determined, and therefore, the control module such as MCU can also determine the resistance of the high-voltage interlocking module 700 based on the first voltage signal in the case that the high-voltage interlocking module 700 is in the on state, in combination with the resistance value of the resistance module 6 and the resistance value of the first voltage detection module 4, through Ohm's law, so as to detect whether the high-voltage interlocking module 700 has contact failure or increased contact resistance, etc., to find potential problems in advance, thereby preventing the high-voltage interlocking from failing.

[0054] In this embodiment, by using the constant current source 2, the first voltage detection module 4 and the resistance module 6, the complexity of the high-voltage interlocking detection circuit is significantly reduced. The circuit does not use an integrated IC for generating a PWM signal and an operational amplifier, only a small amount of MCU port resources are occupied, the circuit design is simplified, and the design cost is greatly reduced. More importantly, the circuit not only can accurately determine the on-off state of the high-voltage interlocking module 700, but also can identify the resistance value of the external total resistance by detecting the voltage value of the first voltage signal in combination with the known resistance value, so as to detect whether the high-voltage interlocking module 700 has contact failure or increased contact resistance, find potential problems in advance, and prevent the high-voltage interlocking from failing.

[0055] In an exemplary embodiment, the high-voltage interlock detection circuit further comprises a control module. The control module is connected to the third end of the first voltage detection module 4, and is configured to determine the on-off state of the high-voltage interlock module 700 according to the first voltage signal; and / or, the control module is configured to determine the resistance value of the high-voltage interlock module 700 according to the first voltage signal in the on state when it is determined that the high-voltage interlock module 700 is in the on state.

[0056] Exemplarily, the high-voltage interlock detection circuit can further comprise an integrated control module. As described in the above embodiment, the control module can determine the on-off state of the high-voltage interlock module 700 based on the first voltage signal, and can also determine the resistance value of the high-voltage interlock module 700 according to the first voltage signal in the on state when it is determined that the high-voltage interlock module 700 is in the on state. The specific determination process can refer to the description in the above embodiment, which will not be described here again.

[0057] In this embodiment, by introducing the control module, not only can the on-off state of the high-voltage interlock module 700 be accurately determined according to the first voltage signal, but also the resistance value of the high-voltage interlock module 700 can be determined by analyzing the first voltage signal when the high-voltage interlock module 700 is in the on state, so as to detect whether there is a poor contact or an increased contact resistance. The circuit structure is simplified, the design cost and complexity are reduced, and the monitoring capability and fault prediction capability of the system are improved, thereby ensuring the stability and safety of the high-voltage interlock system.

[0058] In an exemplary embodiment, as shown in Figure 2 The first voltage detection module 4 comprises a first voltage dividing unit 42 and a first sampling unit 44. The first end of the first voltage dividing unit 42 is connected to the output end of the constant current source 2, and the second end of the first voltage dividing unit 42 is respectively connected to the first end of the resistance module 6 and the first end of the high-voltage interlock module 700. The first end of the first sampling unit 44 is connected to the first end of the first voltage dividing unit 42, and the second end of the first sampling unit 44 is configured to output the first voltage signal.

[0059] Exemplarily, the high-voltage interlock detection circuit provides a constant current through the constant current source 2, which passes through the first voltage dividing unit 42 and the resistance module 6. The resistance values of the first voltage dividing unit 42 and the resistance module 6 determine the voltage drop under different high-voltage interlock states. The first sampling unit 44 detects the voltage at the first end of the first voltage dividing unit 42 and outputs the first voltage signal. When the high-voltage interlock module 700 is on, the resistance module 6 is short-circuited, and the first voltage signal has a lower voltage value; when the high-voltage interlock module 700 is off, the current passes through the resistance module 6, and the first voltage signal has a higher voltage value. By detecting the change of the voltage value of the first voltage signal, the on-off state of the high-voltage interlock module 700 can be accurately determined, thereby achieving simple, low-cost and efficient monitoring of the high-voltage interlock detection circuit.

[0060] In the embodiment, the design of the high-voltage interlock detection circuit is significantly simplified by using the constant current source 2, the first voltage dividing unit 42, and the first sampling unit 44. The design does not rely on complex PWM signal generation and processing circuits, avoids the use of expensive integrated ICs, and thus reduces the cost and design complexity. At the same time, the circuit only needs to occupy a small amount of MCU port resources, further simplifying the system design. By detecting the change of the first voltage signal, the on-off state of the high-voltage interlock module 700 can be accurately judged, realizing simple, low-cost and efficient monitoring of the high-voltage interlock detection circuit, and improving the reliability and economy of the system.

[0061] In an exemplary embodiment, the first sampling unit 44 includes a first sampling resistor and a second sampling resistor. The first end of the first sampling resistor is connected to the first end of the resistance module 6; the first end of the second sampling resistor is connected to the second end of the first sampling resistor, and the first end of the second sampling resistor is used to output the first voltage signal.

[0062] Exemplarily, the common end between the first sampling resistor and the second sampling resistor is used as the output end of the first voltage signal, and the voltage signal is accurately measured through the voltage dividing network. The combination of the first sampling resistor and the second sampling resistor can divide the voltage signal generated by the constant current source 2 through the resistance module 6, so as to output a voltage signal suitable for the input range of the ADC port of the MCU at the first end of the second sampling resistor.

[0063] In the embodiment, by using the sampling unit composed of the first sampling resistor and the second sampling resistor, the design of the high-voltage interlock detection circuit is further simplified, not only reducing the dependence on external complex circuits, reducing the cost and design complexity, but also realizing accurate detection of the on-off state of the high-voltage interlock module 700 through a simple resistance voltage dividing network. The output of the first voltage signal can be completed by only two sampling resistors, occupying very few MCU port resources, improving the reliability and economy of the system, and at the same time ensuring the accuracy and response speed of the detection.

[0064] In an exemplary embodiment, as shown in Figure 3 the high-voltage interlock detection circuit further includes a second voltage detection module 8. The first end of the second voltage detection module 8 is connected to the second end of the resistance module 6 and the second end of the high-voltage interlock module 700, respectively, and the second end of the second voltage detection module 8 is used to output a second voltage signal, which is used to represent the working state of the high-voltage interlock detection circuit.

[0065] Exemplarily, in the case that it is determined that the high-voltage interlock module 700 is in the on state, based on the high-voltage interlock detection circuit described above, a second voltage detection module 8 can also be added to detect the voltage drop of the second end of the resistance module 6 and output in the form of a second voltage signal to a control module such as an MCU, so that the control module such as the MCU can complete the self-checking of the high-voltage interlock detection circuit based on the first voltage signal in combination with the second voltage signal. For example, in the case that an open circuit occurs between the first end and the second end of the first voltage detection module 4, since the constant current output by the constant current source 2 cannot flow to the resistance module 6 and the second voltage detection module 8, the voltage value of the second voltage signal will be zero, while the voltage value of the first voltage signal is proportional to the voltage value of the supply voltage of the constant current source 2. Therefore, when the voltage value of the output first voltage signal is proportional to the voltage value of the supply voltage of the constant current source 2, and the voltage value of the output second voltage signal is zero, the two voltage signals output at this time can represent that an open circuit occurs between the first end and the second end of the first voltage detection module 4 in the high-voltage interlock detection circuit. For another example, in the case that an open circuit occurs between the first end and the third end of the first voltage detection module 4, since the constant current of the constant current source 2 cannot flow to the third end of the first voltage detection module 4, but can normally flow through the resistance module 6 and the first voltage module between the first end and the second end of the first voltage detection module 4, the voltage value of the first voltage signal will be zero, while the voltage value of the second voltage signal is the product of the self-resistance of the second voltage module and the constant current. Therefore, when the voltage value of the output first voltage signal is zero, and the voltage value of the output second voltage signal is the product of the self-resistance of the second voltage module and the constant current, the two voltage signals output at this time can represent that an open circuit occurs between the first end and the third end of the first voltage detection module 4 in the high-voltage interlock detection circuit. For another example, in the case that the second end of the first voltage detection module 4 or the first end of the second voltage detection module 8 is short-circuited to the ground, the voltage value of the first voltage signal is the product of the self-resistance of the first voltage detection module 4 and the constant current, and the voltage value of the second voltage signal is zero. Therefore, when the voltage value of the output first voltage signal is the product of the self-resistance of the first voltage detection module 4 and the constant current, and the voltage value of the output second voltage signal is zero, the two voltage signals output at this time can represent that the second end of the first voltage detection module 4 or the first end of the second voltage detection module 8 is short-circuited to the ground in the high-voltage interlock detection circuit. Through the second voltage signal of the second voltage detection module 8 in combination with the first voltage signal, in addition to the fault diagnosis of the first voltage detection module 4 as described above, other fault diagnoses of the high-voltage interlock detection circuit (such as short-circuit of the first voltage detection module 4 or the second voltage detection module 8 to the power supply) can also be realized, and the specific diagnosis process is not discussed here, and those skilled in the art can know it based on the structure of the high-voltage interlock detection circuit.

[0066] In this embodiment, by introducing the second voltage detection module 8, the self-checking ability and fault diagnosis ability of the high-voltage interlock detection circuit are significantly enhanced. The module can detect and output a second voltage signal reflecting the working state of the high-voltage interlock detection circuit, and in combination with the first voltage signal, it can accurately judge the possible fault types in the circuit, such as open circuit, short circuit, etc., thereby greatly improving the reliability and safety of the system.

[0067] In an exemplary embodiment, the high-voltage interlock detection circuit further comprises a control module. The control module is connected to the third end of the first voltage detection module 4 and the second end of the second voltage detection module 8, respectively. The control module is used to determine the fault condition of the first voltage detection module 4 and the second voltage detection module 8 according to the first voltage signal and the second voltage signal when the high-voltage interlock module 700 is in the on state.

[0068] Exemplarily, the high-voltage interlock detection circuit can also include an integrated control module. As described in the above embodiment, the control module can determine the fault condition of the first voltage detection module 4 and the second voltage detection module 8 based on the first voltage signal and the second voltage signal. The specific determination process can refer to the description in the above embodiment, which will not be repeated here.

[0069] In this embodiment, by integrating the control module, the automatic detection and diagnosis of the fault condition of the first voltage detection module 4 and the second voltage detection module 8 in the high-voltage interlock detection circuit are realized. The control module can accurately determine the working state and fault type of each part of the circuit based on the analysis of the first voltage signal and the second voltage signal, effectively improving the self-monitoring ability and fault response speed of the system, enhancing the reliability and safety of the system, and simplifying the fault troubleshooting process and reducing the maintenance cost.

[0070] In an exemplary embodiment, as shown in Figure 4 The second voltage detection module 8 includes a second voltage dividing unit 82 and a second sampling unit 84. The first end of the second voltage dividing unit 82 is connected to the second end of the resistance module 6 and the second end of the high-voltage interlock module 700, respectively. The first end of the second sampling unit 84 is connected to the first end of the second voltage dividing unit 82, and the second end of the second sampling unit 84 is used to output the second voltage signal.

[0071] In this embodiment, by the design of the second voltage dividing unit 82 and the second sampling unit 84 in the second voltage detection module 8, the voltage of a specific node in the circuit can be accurately detected, and the second voltage signal can be output through the second sampling unit 84 to realize real-time monitoring of the circuit state. This not only improves the accuracy and reliability of voltage detection, but also simplifies the circuit structure, reduces the system cost, and enhances the safety and stability of the system, especially suitable for application occasions requiring high-precision voltage monitoring, such as high-voltage system monitoring of electric vehicles.

[0072] In an exemplary embodiment, the second voltage dividing unit 82 comprises a plurality of voltage dividing resistors. The voltage dividing resistors are respectively connected to the second ends of the resistance modules 6 and the second end of the high voltage interlock module 700, and the first end of the second sampling unit 84.

[0073] Exemplarily, by connecting a plurality of voltage dividing resistors in parallel, the redundancy of the circuit can be increased. Even if one or several resistors fail, the other resistors can still continue to work, ensuring the normal operation of the basic function of the high voltage interlock detection circuit for detecting the on-off state of the high voltage interlock module 700. Secondly, by selecting resistors with different resistance values, the total resistance value can be fine-tuned, so that the required voltage dividing ratio can be more accurately achieved.

[0074] In an exemplary embodiment, as shown in Figure 5 the resistance values of the plurality of voltage dividing resistors are equal, and the high voltage interlock detection circuit further comprises a switching unit 10 and a replacement resistor 12. The first end of the switching unit 10 is used to input a control signal, the second end of the switching unit 10 is connected to the second end of the second voltage dividing unit 82; the first end of the replacement resistor 12 is connected to the third end of the switching unit 10, the second end of the replacement resistor 12 is respectively connected to the second end of the resistance module 6 and the first end of the second sampling unit 84, and the resistance value of the replacement resistor 12 is equal to that of the voltage dividing resistors.

[0075] Exemplarily, by selecting a plurality of voltage dividing resistors with equal resistance values and a replacement resistor 12, when one of the plurality of voltage dividing resistors fails, the replacement resistor 12 can be connected in parallel with the other resistors except the failed voltage dividing resistor based on the on-off control of the switching unit 10, so that the voltage value of the second voltage signal output by the second sampling unit 84 returns to normal. For example, assuming there are two voltage dividing resistors, in the case where the switching unit 10 is not inputted with a control signal, the switching unit 10 remains in an open state, and the replacement resistor 12 is not connected in parallel with the voltage dividing resistors, at this time the voltage value of the second voltage signal output by the second sampling unit 84 is the product of the resistance value after the two voltage dividing resistors are connected in parallel and the constant current. In the case where the voltage value of the second voltage signal increases, the switching unit 10 can be closed based on the driving of the control signal, so that the replacement resistor 12 is connected in parallel with the voltage dividing resistors, at this time the voltage value of the second voltage signal just returns to the product of the resistance value after the two voltage dividing resistors are connected in parallel and the constant current, which indicates that one of the two voltage dividing resistors fails at this time, thereby confirming that the first end of the second voltage detection module 8 is sampled with a fault.

[0076] In the embodiment, by using multiple voltage division resistors with equal resistance and the replacement resistor 12, and combining the control of the switch unit 10, the first end sampling fault of the second voltage detection module 8 can be quickly detected and confirmed. When the voltage value of the second voltage signal is detected to be abnormally increased, the switch unit 10 is closed based on the control signal, and the replacement resistor 12 is connected in parallel to the circuit. If the voltage value of the second voltage signal returns to the normal level, it is immediately confirmed that one of the voltage division resistors is failed. Not only the quick detection and positioning of the fault are realized, but also the fault is automatically repaired without interrupting the circuit operation, which greatly improves the reliability and maintenance efficiency of the system.

[0077] In an exemplary embodiment, the high-voltage interlock detection circuit further comprises a control module. The control module is configured to determine that the first end sampling fault of the second voltage detection module 8 occurs when the first voltage signal when the switch unit 10 is connected to the control signal is equal to the first reference signal, and the second voltage signal when the switch unit 10 is connected to the control signal is equal to the second reference signal, in the case that the high-voltage interlock module 700 is in the on state. The first reference signal is the first voltage signal when the high-voltage interlock detection circuit is not faulty and the high-voltage interlock module 700 is in the on state. The second reference signal is the second voltage signal when the high-voltage interlock detection circuit is not faulty and the high-voltage interlock module 700 is in the on state.

[0078] Exemplarily, the high-voltage interlock detection circuit can also integrate the control module. By comparing the first voltage signal and the second voltage signal with the first reference signal and the second reference signal through the control module in the on state of the high-voltage interlock module 700, and combining the control signal of the switch unit 10, the first end sampling fault of the second voltage detection module 8 can be quickly and accurately detected and determined. Not only the accuracy and speed of fault detection are improved, but also the automatic fault diagnosis is realized, the need for manual intervention is reduced, and the reliability and maintenance efficiency of the system are enhanced.

[0079] In an embodiment, in order to more specifically describe the technical solutions of the present application, the following will be described in combination with the accompanying drawings. Figure 6

[0080] As Figure 6 ​As shown, the high-voltage interlock detection circuit of the present application specifically comprises a constant current source A1, a first voltage detection module 4, a resistance module 6 and a second voltage detection module 8. Among them, in the automotive electronic system, the power supply voltage of the constant current source A1 can be the 12V voltage input by the automotive electronic control unit (ECU) in the anti-reverse, filtering, voltage boosting, voltage reducing conditioning circuit, and the 5V voltage output by the system basis chip (SBC) on the board after the system basis chip (SBC), and the 12V voltage output by the SBC also includes a 5V voltage, which is used to power other elements of the automotive electronic system. The constant current source A1 outputs a constant current of 10mA under the action of the 5V power supply voltage. The first voltage detection module 4 specifically comprises a first voltage dividing unit 42 composed of a resistor R1, a first sampling unit 44 composed of a first sampling resistor R9 and a second sampling resistor R11, and the HVIL_OUT_AI port is used to output a first voltage signal V HVIL_OUT_AI . The resistance module 6 mainly comprises a resistor R2, and the two ends of the resistor R2 are used to be connected in parallel to the high-voltage interlock module 700 composed of the BMS high-voltage connector, the electric drive high-voltage connector, the OBC high-voltage connector, the DC-DC high-voltage connector and the air conditioner high-voltage connector in series. The second voltage detection module 8 specifically comprises a second voltage dividing unit 82 composed of a first voltage dividing resistor R3 and a second voltage dividing resistor R4 connected in parallel, and a second sampling unit 84 composed of a resistor R6. On this basis, the high-voltage interlock detection circuit of the present application further comprises a replacement resistor 12 composed of a resistor R5 and a switching unit 10 composed of a MOS tube Q12, wherein the first end of the switching unit 10, i.e. the gate of the MOS tube, is also connected to the HVIL_DIG port through the resistor R7 and the resistor R8 to receive the control signal, and the HVIL_IN_AI port is used to output a second voltage signal V HVIL_IN_A . Among them, the resistance values of each resistor can be directly obtained by those skilled in the art from the figure.

[0081] In the case that the high-voltage interlock module 700 is in the off state, at this time the MOS tube is in the off state, at this time the first voltage signal V HVIL_OUT_AII output by the HVIL_OUT_AI port is (R1+R2+R3 / / R4)×10mA = (33+200+150)×10=3830mV, and the second voltage signal V HVIL_IN_A output by the HVIL_IN_AI port is (R3 / / R4)×10mA = 150×10=1500mV; in the case that the high-voltage interlock module 700 is in the on state, at this time the MOS tube is still in the off state, at this time the first voltage signal V HVIL_OUT_AII= (R1+R3 / / R4) x 10 mA = (33+150) x 10 = 1830 mV, the second voltage signal V HVIL_IN_A = (R3 / / R4) x 10 mA = 150 x 10 = 1500 mV. The first voltage signal V HVIL_OUT_AII = 0 V, the second voltage signal V HVIL_OUT_AI = 3830 mV can be determined as completely disconnected, when V HVIL_OUT_AI = 1830 mV can be determined as completely connected, and the high-voltage interlock resistance is zero. However, in fact, the high-voltage interlock resistance is generally not zero, so when the first voltage signal V HVIL_OUT_AI is between 1830 mV and 3830 mV, the resistance of the high-voltage interlock module 700 can be determined based on Ohm's law, assuming that the resistance of the high-voltage interlock module 700 is Rx, and V HVIL_OUT_AI = (R1+R2 / / Rx+R3 / / R4) x 10 mA, which is simplified to get the expression of the resistance Rx of the high-voltage interlock module 700: Rx = (20000 V HVIL_OUT_AI - 37000) / (385-100 V HVIL_OUT_AI ), where V HVIL_OUT_AI is in volts V, so in the case of detecting the voltage value of the first voltage signal, the resistance of the high-voltage interlock module 700 can be obtained based on the above expression of the resistance Rx of the high-voltage interlock module 700.

[0082] In addition, when the high-voltage interlock module 700 is in the on state, the self-check of the high-voltage interlock detection circuit can also be completed based on the first voltage signal and the second voltage signal.

[0083] In the case of open circuit of the resistance R1 of the first voltage sampling module, the constant current output by the constant current source A1 forms a loop through the first sampling resistor R9 and the second sampling resistor R11 to ground, but since the resistance of the first sampling resistor R9 and the second sampling resistor R11 is 10 kΩ, the voltage drop based on the voltage division on the resistor R11 is theoretically 10 kΩ x 10 mA = 100 V, but in fact, since the output voltage of the constant current source A1 cannot be greater than the supply voltage 5 V, the first voltage signal V HVIL_OUT_AI = 2.5 V, and the second voltage signal V HVIL_IN_AI = 0 V; therefore, based on the above conditions, it can be determined that the resistance R1 is open circuit fault.

[0084] When the resistance R9 of the first voltage sampling module is in open circuit, the constant current output by the constant current source A1 forms a loop through the resistance R1, the high-voltage interlock module 700, the resistance R3 and the resistance R4 to ground, so the first voltage signal V HVIL_OUT_AI = 0 V, and the second voltage signal V HVIL_IN_AI= (R3 / / R4) x 10 mA = 150 x 10 = 1500 mV, thus, based on the above conditions, it can be determined that the open circuit fault of the resistance R9.

[0085] In the case that the resistance R3 or the resistance R4 is in open circuit, and the level of the gate of the MOS tube is set to low, at this time, the MOS tube is in the off state, at this time, the first voltage signal V HVIL_OUT_AI = (33 + 300) x 10 mA = 3330 mV, the second voltage signal V HVIL_IN_AI = 300 x 10 mA = 3000 mV; the control signal is input to the HVIL_DIG port, that is, the level of the gate of the MOS tube is set to high, and the resistance 12R5 is replaced with the resistance R3 or the resistance R4 in parallel, at this time, the first voltage signal V HVIL_OUT_AI = (33 + 150) x 10 mA = 1830 mV, the second voltage signal V HVIL_IN_AI = (150) x 10 mA = 1500 mV, by comparing and analyzing the above first voltage signal and the second voltage signal, it can be determined whether the first end sampling of the first voltage detection module 4 has a fault.

[0086] In the case that one end of the resistance R2 is short-circuited to the 12V power supply output by the SBC, the first voltage signal V HVIL_OUT_AI = 12V, the second voltage signal V HVIL_IN_AI = 12V, thus, based on the above conditions, it can be determined that the high-voltage interlock detection circuit has a short power supply fault; similarly, in the case that one end of the resistance R2 is short-circuited to the ground, the first voltage signal V HVIL_OUT_AI = R1 x 10 mA ≈ 330 mV, the second voltage signal V HVIL_IN_AI = 10V, thus, based on the above conditions, it can be determined that the high-voltage interlock detection circuit has a short ground fault.

[0087] In the embodiment, the selection of the above electronic components can be selected according to the actual design needs, the specific values of the above electronic components, and the on-off state judgment process of the high-voltage interlock module, the resistance determination process of the high-voltage interlock module, and the self-diagnosis process of the high-voltage interlock detection circuit based on the above specific values are only for illustration and are not limited herein. In the above embodiment, by replacing the complex PWM signal with a common voltage signal, the use of MCU port resources is significantly reduced, and the use of the PWM generator is abandoned, thereby reducing the development cost and the complexity of circuit design. Only using common resistors and NMOS tubes can realize the design of the high-voltage interlock detection circuit, which not only simplifies the circuit structure, but also has the ability to collect external resistance values. More importantly, the circuit design has a powerful self-diagnosis function, which can quickly and accurately detect and locate various faults, and the self-contained safety mechanism meets the functional safety level ASIL B requirement, thereby greatly improving the reliability and safety of the system.

[0088] In one exemplary embodiment, the application also provides a vehicle comprising a high-voltage interlock module and a high-voltage interlock detection circuit as in the above embodiments.

[0089] In this embodiment, by integrating the high-voltage interlock module and the improved high-voltage interlock detection circuit in the vehicle, the safety and reliability of the vehicle electrical system are significantly improved. The detection circuit can quickly and accurately detect the on-off state of the high-voltage interlock module and circuit faults, especially open circuit, short circuit and other faults commonly found in high-voltage systems, so that timely measures can be taken to prevent potential safety hazards. Not only does this enhance the vehicle's self-monitoring and fault diagnosis capabilities, but it also simplifies maintenance procedures, reduces maintenance costs, and ensures long-term stable operation of the vehicle.

[0090] In the description of the present specification, the description referring to the terms "some embodiments", "other embodiments", and the like means that the specific features, structures, materials or characteristics described in connection with the embodiments or examples are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example.

[0091] The technical features of the above-described embodiments can be combined in any manner. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described, however, as long as the combinations of the technical features do not contradict each other, they should be considered within the scope of the present application.

[0092] The above-described embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the scope of the present application. It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A high voltage interlock detection circuit, characterized by, The high-voltage interlock detection circuit comprises: a constant current source; a first voltage detection module, a first end of the first voltage detection module being connected to an output end of the constant current source; a resistance module, first ends of the resistance module being respectively connected to second ends of the first voltage detection module and a first end of a high-voltage interlock module, and a second end of the resistance module being connected to a second end of the high-voltage interlock module; wherein a third end of the first voltage detection module is used to output a first voltage signal, and the first voltage signal is used to represent an on-off state of the high-voltage interlock module; wherein a resistance value of the resistance module and a resistance value of the first voltage detection module are known; The high-voltage interlock detection circuit further comprises: a control module, the control module being connected to the third end of the first voltage detection module, and the control module being used to determine the on-off state of the high-voltage interlock module according to the first voltage signal; the control module being used to determine a resistance value of the high-voltage interlock module according to the first voltage signal in the on state when it is determined that the high-voltage interlock module is in the on state, and the resistance value of the high-voltage interlock module being used to determine whether the high-voltage interlock module has a poor contact or an increased contact resistance.

2. The high voltage interlock detection circuit of claim 1, wherein, The first voltage detection module comprises: a first voltage dividing unit, a first end of the first voltage dividing unit being connected to the output end of the constant current source, and second ends of the first voltage dividing unit being respectively connected to the first ends of the resistance module and the first end of the high-voltage interlock module; a first sampling unit, a first end of the first sampling unit being connected to the first end of the first voltage dividing unit, and a second end of the first sampling unit being used to output the first voltage signal.

3. The high voltage interlock detection circuit of claim 2, wherein, The first sampling unit comprises: a first sampling resistor, a first end of the first sampling resistor being connected to the first end of the resistance module; a second sampling resistor, a first end of the second sampling resistor being connected to a second end of the first sampling resistor, and a first end of the second sampling resistor being used to output the first voltage signal.

4. The high-voltage interlock detection circuit of any one of claims 1-3, wherein, The high-voltage interlock detection circuit further comprises: a second voltage detection module, first ends of the second voltage detection module being respectively connected to the second end of the resistance module and the second end of the high-voltage interlock module, and a second end of the second voltage detection module being used to output a second voltage signal, the second voltage signal being used to represent a working state of the high-voltage interlock detection circuit.

5. The high voltage interlock detection circuit of claim 4, wherein, The second voltage detection module comprises: a second voltage dividing unit, first ends of the second voltage dividing unit being respectively connected to the second end of the resistance module and the second end of the high-voltage interlock module; a second sampling unit, a first end of the second sampling unit being connected to the first end of the second voltage dividing unit, and a second end of the second sampling unit being used to output the second voltage signal.

6. The high voltage interlock detection circuit of claim 5, wherein, The second voltage dividing unit comprises: a plurality of voltage dividing resistors, the voltage dividing resistors being respectively connected to the second end of the resistance module and the second end of the high-voltage interlock module, and the first end of the second sampling unit.

7. The high voltage interlock detection circuit of claim 6, wherein, The resistance values of the plurality of voltage dividing resistors are equal, and the high-voltage interlock detection circuit further comprises: A switch unit, a first end of the switch unit is used for accessing a control signal, a second end of the switch unit is connected with a second end of the second voltage dividing unit; A replacement resistor, a first end of the replacement resistor is connected with a third end of the switch unit, a second end of the replacement resistor is connected with a second end of the resistance module and a first end of the second sampling unit respectively, the replacement resistor and the voltage dividing resistor have equal resistance.

8. The high voltage interlock detection circuit of claim 4, wherein, The high-voltage interlock detection circuit further comprises: A control module, the control module is connected with a third end of the first voltage detection module and a second end of the second voltage detection module respectively, the control module is used for determining a fault condition of the first voltage detection module and the second voltage detection module according to the first voltage signal and the second voltage signal when the high-voltage interlock module is in a conducting state.

9. The high voltage interlock detection circuit of claim 7, wherein, The high-voltage interlock detection circuit further comprises: A control module, the control module is used for determining that a first end of the second voltage detection module is faulty when it is detected that the first voltage signal when the switch unit accesses the control signal is equal to a first reference signal and the second voltage signal when the switch unit accesses the control signal is equal to a second reference signal when the high-voltage interlock module is in a conducting state. The first reference signal is the first voltage signal when the high-voltage interlock detection circuit is not faulty and the high-voltage interlock module is in a conducting state, and the second reference signal is the second voltage signal when the high-voltage interlock detection circuit is not faulty and the high-voltage interlock module is in a conducting state.

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