High-voltage interlock circuits, systems, and high-voltage interlock testing methods

Abstract

This invention discloses a high-voltage interlock circuit, system, and high-voltage interlock detection method. A triangular wave conversion module connects its first detection input to the input of the interlock circuit and its second detection input to the output of the interlock circuit. The triangular wave conversion module converts the signals input from the first and second detection inputs into a triangular wave signal based on a first PWM signal received by a PWM signal receiver. The PWM wave conversion module then generates a second PWM signal from the triangular wave signal and a set voltage threshold, which is output to a diagnostic module. The diagnostic module can determine the fault type of the interlock circuit based on the duty cycle of the second PWM signal. This invention allows the diagnostic module to diagnose the fault type of the interlock circuit with only one sampling input port, making fault diagnosis of the interlock circuit easier and reducing the number of ports in the diagnostic module, thus saving resources.

Description

Technical Field

[0001] The present invention relates to the field of electronic circuit control technology, and in particular to a high-voltage interlock circuit, system and high-voltage interlock detection method. Background Technology

[0002] With the rapid development of new energy vehicles, their safety has become a major concern. Among these concerns, the high-voltage interlock circuit plays a crucial role in high-voltage circuit monitoring systems.

[0003] Existing high-voltage interlock circuits typically include a high-voltage interlock circuit. This circuit detects the connection status of high-voltage connectors within the high-voltage circuit, thereby identifying faults such as connector disconnection or accidental disconnection. Current high-voltage interlock circuits generally employ a PWM control scheme. When the high-voltage interlock is normally closed, the battery management system inputs a PWM signal to the high-voltage interlock circuit and then samples the PWM signal back to determine if the high-voltage interlock function is working properly.

[0004] However, the duty cycle of the PWM signal output by the existing high-voltage interlock circuit is almost equal for different faults. This means that when making specific fault judgments for high-voltage interlock, an additional analog signal sampling function is required. As a result, the microcontroller used for sampling in the battery management system needs to be equipped with multiple sampling ports, making the implementation of fault diagnosis more complicated. Summary of the Invention

[0005] This invention provides a high-voltage interlock circuit, system, and high-voltage interlock detection method, so that the high-voltage interlock circuit can output duty cycles that are not completely the same when the fault type of the interlock circuit is different, making it easier to determine the fault type of the interlock circuit and reducing the number of ports in the diagnostic module.

[0006] In a first aspect, embodiments of the present invention provide a high-voltage interlock circuit, comprising: a triangular wave conversion module, a PWM wave conversion module, and an interlock circuit;

[0007] The triangular wave conversion module includes a first detection input terminal, a second detection input terminal, a PWM signal receiving terminal, and a triangular wave output terminal. The first detection input terminal is connected to the input terminal of the interlocking circuit, and the second detection input terminal is connected to the output terminal of the interlocking circuit. The triangular wave conversion module is used to convert the first PWM signal received by the PWM signal receiving terminal into a triangular wave signal based on the signals input to the first and second detection input terminals. The slope of the triangular wave signal is related to the signals input to the first and second detection input terminals.

[0008] The input terminal of the PWM wave conversion module is electrically connected to the output terminal of the triangular wave. The output terminal of the PWM wave conversion module serves as the output terminal of the high-voltage interlock circuit. The PWM wave conversion module is used to generate a second PWM signal based on the triangular wave signal and the set voltage and output it to the diagnostic module so that the diagnostic module can determine the fault type of the interlock circuit based on the duty cycle of the second PWM signal.

[0009] Optionally, the triangular wave conversion module includes an integrating circuit;

[0010] The integrator circuit includes an operational amplifier and an RC circuit. The RC circuit is electrically connected to the non-inverting input terminal and the output terminal of the operational amplifier. The inverting input terminal of the operational amplifier is connected to the PWM signal receiving terminal. The output terminal of the operational amplifier serves as the output terminal of the integrator circuit, and the output terminal of the integrator circuit serves as the triangular wave output terminal.

[0011] The RC circuit is electrically connected to the first detection input terminal and the second detection input terminal.

[0012] Optionally, the RC circuit includes a first voltage divider circuit and a capacitor feedback branch. The voltage divider output terminal of the first voltage divider branch is electrically connected to the non-inverting input terminal of the operational amplifier. The first terminal of the capacitor feedback branch is connected to the output terminal of the operational amplifier, and the second terminal of the capacitor feedback branch is connected to the inverting input terminal of the operational amplifier.

[0013] The capacitor feedback branch includes n capacitors connected in series at the first and second ends of the capacitor feedback branch. The first node in the capacitor feedback branch serves as the first detection input terminal, and the second node in the capacitor feedback branch serves as the second detection input terminal. i capacitors are connected in series between the first node and the second node, where 1≤i≤n-1 and i is an integer, and n is an integer greater than or equal to 2.

[0014] Optionally, the capacitor feedback branch includes a first capacitor and a second capacitor connected in series. The first terminal of the first capacitor serves as the first terminal of the capacitor feedback branch, and the second terminal of the first capacitor is electrically connected to the first terminal of the second capacitor. The second terminal of the second capacitor serves as the second terminal of the capacitor feedback branch.

[0015] The second terminal of the first capacitor serves as the first node, and the second terminal of the second capacitor serves as the second node.

[0016] Optionally, the first voltage divider circuit includes a first resistor and a second resistor, which are connected in series between the power input terminal and the ground terminal, and the common terminal of the first resistor and the second resistor is connected to the voltage divider output terminal.

[0017] Optionally, the PWM wave conversion module includes a comparator and a second voltage divider circuit. The non-inverting input of the comparator serves as the input of the PWM wave conversion module, and the inverting input of the comparator is electrically connected to the output of the second voltage divider circuit. The output of the comparator serves as the output of the PWM wave conversion module. The second voltage divider circuit is used to generate a set voltage.

[0018] Optionally, the interlock circuit includes multiple high-voltage electrical components, each connected in series between the input and output terminals of the interlock circuit.

[0019] In a second aspect, embodiments of the present invention also provide a high-voltage interlock system, including the high-voltage interlock circuit of the first aspect, and further including a diagnostic module;

[0020] The PWM signal output terminal of the diagnostic module is electrically connected to the PWM signal receiving terminal of the high-voltage interlock circuit, and the sampling input terminal of the diagnostic module is electrically connected to the output terminal of the high-voltage interlock circuit. The diagnostic module is used to output a first PWM signal to the PWM signal receiving terminal through the PWM signal output terminal, and to receive a second PWM signal output by the high-voltage interlock circuit through the sampling input terminal, and to determine the fault type of the interlock circuit based on the duty cycle of the second PWM signal.

[0021] Thirdly, embodiments of the present invention also provide a high-voltage interlock detection method, including:

[0022] The first PWM signal is sent from the PWM signal output terminal to the PWM signal receiving terminal of the high-voltage interlock circuit, so that the triangular wave conversion module of the high-voltage interlock circuit converts the first PWM signal received by the PWM signal receiving terminal into a triangular wave signal according to the signals input to the first detection input terminal and the second detection input terminal; wherein the slope of the triangular wave signal is related to the signals input to the first detection input terminal and the second detection input terminal, and the PWM wave conversion module of the high-voltage interlock circuit generates a second PWM signal according to the triangular wave signal and the set voltage and outputs it.

[0023] The fault type of the interlock circuit of the high-voltage interlock circuit is determined based on the duty cycle of the second PWM signal received at the sampling input terminal.

[0024] Optionally, the fault type of the interlock circuit in the high-voltage interlock circuit can be determined based on the duty cycle of the second PWM signal received at the sampling input terminal, including:

[0025] When the duty cycle of the second PWM signal is equal to the first duty cycle, it is determined that there is a disconnection fault in the interlock circuit;

[0026] When the duty cycle of the second PWM signal is equal to the second duty cycle, it is determined that there is a short-to-ground fault at the input of the interlock circuit;

[0027] When the duty cycle of the second PWM signal is equal to the duty cycle of the third PWM signal, it is determined that there is a short power supply fault at the input of the interlock circuit.

[0028] When the duty cycle of the second PWM signal is equal to the fourth duty cycle, it is determined that there is a short-ground or short-power supply fault at the output of the interlock circuit.

[0029] The first duty cycle, the second duty cycle, the third duty cycle, and the fourth duty cycle are all unequal.

[0030] The high-voltage interlock circuit, system, and high-voltage interlock detection method of this invention connect the first detection input terminal of the triangular wave conversion module to the input terminal of the interlock circuit, and the second detection input terminal to the output terminal of the interlock circuit. The triangular wave conversion module converts the first PWM signal received by the PWM signal receiver into a triangular wave signal according to the signals input from the first and second detection input terminals. The PWM wave conversion module generates a second PWM signal based on the triangular wave signal and a set voltage threshold and outputs it to the diagnostic module. Because the slope of the triangular wave signal is related to the signals at the first and second detection input terminals, and these signals are related to the fault type of the interlocking circuit, the signals at the first and second detection input terminals will differ under different fault types. This results in different slopes of the triangular waves converted by the triangular wave conversion module, leading to different duty cycles of the second PWM signal output by the PWM wave conversion module. Consequently, the diagnostic module can determine the fault type of the interlocking circuit based on the duty cycle of the second PWM signal. Therefore, the diagnostic module only needs to set one sampling input port to diagnose the fault type, making fault diagnosis of the interlocking circuit easier and reducing the number of ports in the diagnostic module, thus saving resources. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of a high-voltage interlock circuit provided in an embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of the first PWM signal input to the high-voltage interlock circuit provided in the embodiment of the present invention, which is converted into a triangular wave signal by a triangular wave conversion module and then converted into a second PWM signal by a PWM wave conversion module.

[0033] Figure 3 This is a schematic diagram of another high-voltage interlock circuit provided in an embodiment of the present invention;

[0034] Figure 4 This is a schematic diagram of another high-voltage interlock circuit provided in an embodiment of the present invention;

[0035] Figure 5This is a schematic diagram of another high-voltage interlock circuit provided in an embodiment of the present invention;

[0036] Figure 6 This is a schematic diagram of the structure of a high-voltage interlocking system provided in an embodiment of the present invention;

[0037] Figure 7 This is a flowchart of a high-voltage interlock detection method provided in an embodiment of the present invention;

[0038] Figure 8 This is a flowchart of another high-voltage interlock detection method provided in an embodiment of the present invention. Detailed Implementation

[0039] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0040] Figure 1 This is a schematic diagram of a high-voltage interlock circuit provided in an embodiment of the present invention. Figure 2 This is a schematic diagram illustrating the first PWM signal input to the high-voltage interlock circuit provided in this embodiment of the invention, which is converted into a triangular wave signal by a triangular wave conversion module, and then converted into a second PWM signal by a PWM wave conversion module. (Reference) Figure 1 and Figure 2 The high-voltage interlock circuit 100 includes: a triangular wave conversion module 110, a PWM wave conversion module 120, and an interlock circuit 130;

[0041] The triangular wave conversion module 110 includes a first detection input terminal A1, a second detection input terminal A2, a PWM signal receiving terminal IN1, and a triangular wave output terminal OUT0. The first detection input terminal A1 is connected to the input terminal HVIL_IN of the interlocking loop, and the second detection input terminal A2 is connected to the output terminal HVIL_OUT of the interlocking loop. The triangular wave conversion module 110 is used to convert the first PWM signal received by the PWM signal receiving terminal IN1 into a triangular wave signal according to the signals input by the first detection input terminal A1 and the second detection input terminal A2. The slope of the triangular wave signal is related to the signals input by the first detection input terminal A1 and the second detection input terminal A2.

[0042] The input terminal of the PWM wave conversion module 120 is electrically connected to the triangular wave output terminal OUT0. The output terminal of the PWM wave conversion module 120 serves as the output terminal OUT1 of the high-voltage interlock circuit. The PWM wave conversion module 120 is used to generate a second PWM signal based on the triangular wave signal and the set voltage V0 and output it to the diagnostic module 200 so that the diagnostic module 200 can determine the fault type of the interlock circuit based on the duty cycle of the second PWM signal.

[0043] High Voltage Interlock (HVIL) is a safety design method that uses low-voltage signals to monitor the integrity and continuity of a high-voltage circuit. New energy vehicles include multiple high-voltage devices, and all high-voltage connector connections require a high-voltage interlock signal circuit. The implementation of a high-voltage interlock design requires the following components: a high-voltage interlock connector and high / low voltage conductors, a high-voltage interlock monitoring circuit and monitoring module (the monitoring module can be a battery management system or a vehicle controller), and a high-voltage relay controlled by the monitoring module based on the high-voltage interlock monitoring results. A high-voltage connector with high-voltage interlock functionality includes a housing, a high-voltage conductive component, and a low-voltage signal conductive component. Typically, a high-voltage interlock connector has a pair of high-voltage connectors and a pair of low-voltage connectors fixed to a pair of male and female terminals. When the high-voltage connector is disconnected, the low-voltage circuit is cut off; when the high-voltage connector is connected, the low-voltage circuit is also connected, forming a complete circuit. In this embodiment, the interlock circuit is the aforementioned low-voltage circuit.

[0044] in, Figure 2The central PWM wave is the first PWM signal, the triangular wave is the triangular wave signal converted by the triangular wave conversion module 110, and the converted PWM wave is the second PWM wave signal converted by the PWM wave conversion module 120. Specifically, the triangular wave conversion module 110 can be implemented by a circuit structure that can convert the PWM wave into a triangular wave. The high-voltage interlock circuit also includes an interlock loop 130, in which the first detection input terminal A1 of the triangular wave conversion module 110 is connected to the input terminal HVIL_IN of the interlock loop 130, and the second detection input terminal A2 of the triangular wave conversion module 110 is connected to the output terminal HVIL_OUT of the interlock loop 130. The interlock loop 130 includes multiple high-voltage electrical components, each of which is connected in series between the input terminal HVIL_IN and the output terminal HVIL_OUT of the interlock loop 130. When all high-voltage interlock connectors are normally connected and the interlock circuit 130 is normally closed, the signals at the input terminal HVIL_IN and the output terminal HVIL_OUT of the interlock circuit 130 are the same. Correspondingly, the signals at the first detection input terminal A1 and the second detection input terminal A2 of the triangular wave conversion module 110 are the same. When a high-voltage interlock connector is disconnected or a short-ground or short-power fault exists in the interlock circuit 130, the signals at the input and output terminals of the interlock circuit are different. Correspondingly, the signals at the first detection input terminal A1 and the second detection input terminal A2 of the triangular wave conversion module 110 are different. The signals at the first detection input terminal A1 and the second detection input terminal A2 affect the circuit parameters in the triangular wave conversion module 110. Based on the signals at the first detection input terminal A1 and the second detection input terminal, the triangular wave conversion module 110 converts the first PWM signal received at the PWM signal receiver IN1 into a triangular wave signal. The slope of this triangular wave signal is related to the signals at the first detection input terminal A1 and the second detection input terminal A2.

[0045] The input terminal of the PWM wave conversion module 120 is connected to the triangular wave output terminal OUT0 of the triangular wave conversion module 110. The PWM wave conversion module 120 generates a second PWM signal based on the triangular wave signal received at its input terminal and the set voltage V0. Optionally, the PWM wave conversion module 120 can compare the triangular wave signal with the set voltage threshold to obtain the second PWM signal. Since the slope of the triangular wave signal is related to the signal at the first detection input terminal A1 and the signal at the second detection input terminal A2, and the signals at the first detection input terminal A1 and the second detection input terminal A2 are related to the fault type of the interlocking circuit 130, the signal at the first detection input terminal A1 and / or the signal at the second detection input terminal A2 will differ under different fault types. This results in different slopes of the triangular wave converted by the triangular wave conversion module 110, causing different duty cycles of the second PWM signal output by the PWM wave conversion module 120. Therefore, the diagnostic module 200 can determine the specific fault type of the interlocking circuit based on the duty cycle of the second PWM signal. The diagnostic module 200 can be a battery management system or a vehicle controller in the vehicle. The diagnostic module 200 includes a microcontroller, and the sampling input port of the microcontroller is connected to the output terminal OUT1 of the high-voltage interlock circuit. Therefore, the microcontroller only needs to be configured with one sampling input port to realize the diagnosis of the fault type of the interlock circuit, which makes the fault diagnosis of the interlock circuit 130 easy to realize, and reduces the number of microcontroller ports, saving resources.

[0046] In this embodiment, the high-voltage interlock circuit connects the first detection input terminal of the triangular wave conversion module to the input terminal of the interlock circuit, and the second detection input terminal is connected to the output terminal of the interlock circuit. The triangular wave conversion module converts the first PWM signal received by the PWM signal receiver into a triangular wave signal based on the signals input from the first and second detection input terminals. The PWM wave conversion module then generates a second PWM signal from the triangular wave signal and the set voltage and outputs it to the diagnostic module. Because the slope of the triangular wave signal is related to the signals at the first and second detection input terminals, and these signals are related to the fault type of the interlocking circuit, the signals at the first and second detection input terminals will differ under different fault types. This results in different slopes of the triangular wave converted by the triangular wave conversion module, leading to different duty cycles of the second PWM signal output by the PWM wave conversion module. Consequently, the diagnostic module can determine the fault type of the interlocking circuit based on the duty cycle of the second PWM signal. Therefore, when the diagnostic module includes a microcontroller, the microcontroller only needs to set one sampling input port to diagnose the fault type of the interlocking circuit, making fault diagnosis of the interlocking circuit easier and reducing the number of microcontroller ports, thus saving resources.

[0047] Figure 3This is a schematic diagram of another high-voltage interlock circuit provided in an embodiment of the present invention, for reference. Figure 3 Optionally, the triangular wave conversion module 110 includes an integrating circuit 112; the integrating circuit 112 includes an operational amplifier 111 and an RC circuit 112, the RC circuit 112 is electrically connected to the non-inverting input terminal and the output terminal of the operational amplifier 111, the inverting input terminal of the operational amplifier 111 is connected to the PWM signal receiving terminal IN1; the output terminal of the operational amplifier 111 serves as the output terminal of the integrating circuit; the output terminal of the integrating circuit 112 serves as the triangular wave output terminal OUT0; the RC circuit 112 is electrically connected to the first detection input terminal A1 and the second detection input terminal A2.

[0048] Specifically, the non-inverting input and output of operational amplifier 111 are connected to RC circuit 112. RC circuit 112 is electrically connected to the first detection input A1 and the second detection input A2, respectively. When the interlock circuit is in different states, the signals of the first detection input A1 and / or the second detection input A2 will be different. Correspondingly, the circuit parameters of RC circuit 112 will be different, causing the slope of the triangular wave output by operational amplifier 111 to change. This causes the duty cycle of the second PWM signal output by PWM wave conversion module 120 to change when the triangular wave signal is input to PWM wave conversion module 120.

[0049] Continue to refer to Figure 3 Optionally, the RC circuit 112 includes a first voltage divider circuit 1121 and a capacitor feedback branch 1122. The voltage divider output terminal of the first voltage divider circuit 1121 is electrically connected to the non-inverting input terminal of the operational amplifier 111. The first terminal of the capacitor feedback branch 1122 is connected to the output terminal of the operational amplifier 111, and the second terminal of the capacitor feedback branch 1122 is connected to the inverting input terminal of the operational amplifier 111. The capacitor feedback branch 1122 includes n capacitors C connected in series at the first and second terminals of the capacitor feedback branch 1122. The first node in the capacitor feedback branch 1122 serves as the first detection input terminal A1, and the second node in the capacitor feedback branch 1122 serves as the second detection input terminal A2. i capacitors C are connected in series between the first and second nodes, where 1≤i≤n-1 and i is an integer, and n is an integer greater than or equal to 2.

[0050] The first voltage divider circuit 1121 can output the required voltage to the non-inverting input of the operational amplifier 111 through its voltage divider output terminal. Optionally, the first voltage divider circuit 1121 includes a first resistor R1 and a second resistor R2, which are connected in series between the power input terminal VDD and the ground terminal. The common terminal of the first resistor R1 and the second resistor R2 is connected to the voltage divider output terminal. Specifically, the first resistor R1 and the second resistor R2 can be selected with appropriate resistance values ​​based on the voltage required by the non-inverting input of the operational amplifier 111 in the integrating circuit and the input voltage of the power input terminal VDD.

[0051] The capacitor feedback branch 1122 includes n capacitors C connected in series at its first and second ends. A first detection input terminal A1 is connected to the first node in the capacitor feedback branch 1122, and a second detection input terminal A2 is connected to the second node in the same branch. i capacitors C are connected in series between the first and second nodes, where i is a positive integer less than n. When the signals input to the integrator circuit at the first detection input terminal A1 and / or the second detection input terminal A2 change, the total capacitance C in the capacitor feedback branch 1122 changes, causing a change in the slope of the triangular wave output by the triangular wave conversion module 110. This, in turn, changes the duty cycle of the second PWM signal output by the PWM wave conversion module 120 when the triangular wave signal is input to the PWM wave conversion module 120.

[0052] In this embodiment, both the input terminal HVIL_IN and the output terminal HVIL_OUT of the interlock circuit 130 are connected to the capacitor feedback branch 1122. Because capacitor C has high voltage withstand capability, even if the interlock circuit 130 experiences a short-to-ground or short-supply fault, the microcontroller of the diagnostic module 200 will not be damaged. The high-voltage interlock circuit of this embodiment can withstand a large short-supply voltage, thus being compatible with higher voltage power supply platforms and providing protection for the microcontroller of the diagnostic module 200.

[0053] Figure 4 This is a schematic diagram of another high-voltage interlock circuit provided in an embodiment of the present invention, for reference. Figure 4 Optionally, the PWM wave conversion module 120 includes a comparator 121 and a second voltage divider circuit 122. The non-inverting input terminal of the comparator 121 serves as the input terminal of the PWM wave conversion module 120, and the inverting input terminal of the comparator 121 is electrically connected to the output terminal of the second voltage divider circuit 122. The output terminal of the comparator 121 serves as the output terminal of the PWM wave conversion module 120. The second voltage divider circuit 122 is used to generate a set voltage.

[0054] The second voltage divider circuit 122 can output a set threshold voltage to the non-inverting input of the comparator 121 through its own output terminal. Optionally, the second voltage divider circuit 122 includes a third resistor R3 and a fourth resistor R4, which are connected in series between the power input terminal VDD and the ground terminal. The common terminal of the third resistor R3 and the fourth resistor R4 is connected to the non-inverting input of the comparator 121. Specifically, the third resistor R3 and the fourth resistor R4 can be selected with appropriate resistance values ​​based on the set threshold voltage in the integrating circuit and the input voltage of the power input terminal VDD.

[0055] Comparator 121 generates a second PWM signal based on the set voltage input to its non-inverting input terminal and the triangular wave signal input to its inverting input terminal. Under the same set voltage, when the slope of the triangular wave signal input to comparator 121 is different, the duty cycle of the generated second PWM signal is different, so that the diagnostic module 200 can determine the fault type of the interlock circuit based on the duty cycle of the received second PWM signal.

[0056] Figure 5 This is a schematic diagram of another high-voltage interlock circuit provided in an embodiment of the present invention, for reference. Figure 5 In this high-voltage interlock circuit, the triangular wave conversion module 110 includes an integrating circuit; the integrating circuit includes an operational amplifier 111 and an RC circuit 112. The RC circuit 112 is electrically connected to the non-inverting input terminal and the output terminal of the operational amplifier 111. The inverting input terminal of the operational amplifier 111 is connected to the PWM signal receiving terminal IN1. The output terminal of the operational amplifier 111 is connected to the output terminal of the integrating circuit. The RC circuit 112 is electrically connected to the first detection input terminal A1 and the second detection input terminal A2. The RC circuit 112 includes a first voltage divider circuit 1121 and a capacitor feedback branch 1122. The voltage divider output terminal of the first voltage divider circuit is electrically connected to the non-inverting input terminal of the operational amplifier 111. The first voltage divider circuit 1121 includes a first resistor R1 and a second resistor R2. The first resistor R1 and the second resistor R2 are connected in series between the power input terminal VDD and the ground terminal. The common terminal of the first resistor R1 and the second resistor R2 is connected to the voltage divider output terminal. The capacitor feedback branch 1122 includes a first capacitor C1 and a second capacitor C2 connected in series. The first end of the first capacitor C1 serves as the first end of the capacitor feedback branch 1122. The second end of the first capacitor C1 is electrically connected to the first end of the second capacitor C2. The second end of the second capacitor C2 serves as the second end of the capacitor feedback branch 1122. The second end of the first capacitor C1 serves as the first node, and the second end of the second capacitor C2 serves as the second node.

[0057] The PWM wave conversion module 120 includes a comparator 121 and a second voltage divider circuit 122. The non-inverting input of the comparator 121 is electrically connected to the input of the PWM wave conversion module 120, the inverting input of the comparator 121 is electrically connected to the output of the second voltage divider circuit 122, and the output of the comparator 121 is electrically connected to the output of the PWM wave conversion module 120. The second voltage divider circuit 122 is used to generate a set voltage. The second voltage divider circuit 122 includes a third resistor R3 and a fourth resistor R4, which are connected in series between the power input VDD and the ground terminal. The common terminal of the third resistor R3 and the fourth resistor R4 is connected to the non-inverting input of the comparator 121. A fifth resistor R5 is connected between the inverting input of the operational amplifier 111 and the PWM signal receiving terminal IN1.

[0058] The first detection input terminal A1 and the second detection input terminal A2 are connected to the interlocking circuit 130. The following describes the interlocking circuit 130 under different operating states.

[0059] When a break occurs in the interlock circuit 130, both the first capacitor C1 and the second capacitor C2 are connected to the capacitor feedback branch 1122. At this time, the total capacitance of the capacitor feedback branch 1122 is small, and the slope of the triangular wave signal converted by the integrator circuit from the first PWM signal is small. When the triangular wave signal is input to the comparator 121, the duty cycle of the second PWM wave output by the comparator 121 is small. At this time, the duty cycle of the second PWM wave is the first duty cycle, for example, the first duty cycle is 20%.

[0060] When the interlock circuit 130 is normally closed, the signals of the first detection input terminal A1 and the second detection input terminal A2 are the same, which is equivalent to the first capacitor C1 being short-circuited. At this time, the total capacitance C of the capacitor feedback branch 1122 is equal to the second capacitor C2, which increases the total capacitance C of the capacitor feedback branch 1122. The integrator circuit converts the first PWM signal into a triangular wave signal with a larger slope. When the triangular wave signal is input to the comparator 121, the duty cycle of the second PWM wave output by the comparator 121 is larger. At this time, the duty cycle of the second PWM wave is the second duty cycle. For example, the second duty cycle is 40%.

[0061] When the input terminal HVIL_IN of the interlock circuit 130 is shorted to ground, the voltage of the input terminal HVIL_IN of the interlock circuit 130 is 0, the voltage of the first detection input terminal A1 is 0, and correspondingly, the voltage of the output terminal of the integrator circuit is 0. Then the potential of the non-inverting input terminal of the comparator 121 is 0. At this time, the duty cycle of the second PWM wave is the third duty cycle, and the third duty cycle is 0%.

[0062] When a short power supply occurs at the input terminal HVIL_IN of the interlock circuit 130, the voltage at the input terminal HVIL_IN of the interlock circuit 130 is the power supply voltage, the voltage at the first detection input terminal A1 is the power supply voltage, and correspondingly, the voltage at the output terminal of the integrator circuit is the power supply voltage. Then, the potential input to the non-inverting input terminal of the comparator 121 is the power supply voltage. At this time, the duty cycle of the second PWM wave is the third duty cycle, and the third duty cycle is 100%.

[0063] When the output terminal HVIL_OUT of the interlock circuit 130 is shorted to ground or shorted to power, the integrator circuit does not function. At this time, the duty cycle of the second PWM signal is equal to the duty cycle of the first PWM signal.

[0064] This embodiment also provides a high-voltage interlock system. Figure 6 This is a schematic diagram of a high-voltage interlocking system provided in an embodiment of the present invention, for reference. Figure 6 The high-voltage interlock system includes the high-voltage interlock circuit 100 of any of the above embodiments of the present invention, and also includes a diagnostic module 200; the PWM signal output terminal D1 of the diagnostic module 200 is electrically connected to the PWM signal receiving terminal IN1 of the high-voltage interlock circuit, and the sampling input terminal D2 of the diagnostic module 200 is electrically connected to the output terminal OUT1 of the high-voltage interlock circuit; the diagnostic module 200 is used to output a first PWM signal to the PWM signal receiving terminal IN1 through the PWM signal output terminal D1, and to receive a second PWM signal output by the high-voltage interlock circuit through the sampling input terminal D2, and to determine the fault type of the interlock circuit according to the duty cycle of the second PWM signal.

[0065] The diagnostic module 200 can be a battery management system or a vehicle controller in the vehicle. The diagnostic module 200 may include a microcontroller. The diagnostic module 200 can send a first PWM signal to the PWM signal receiving terminal IN1 of the high-voltage interlock circuit, and receive a second PWM signal output by the high-voltage interlock circuit 100 based on the first PWM signal, and determine the fault type of the interlock circuit based on the duty cycle of the second PWM signal.

[0066] The high-voltage interlock system of this embodiment has the beneficial effects of the high-voltage interlock circuit of any of the above embodiments of the present invention.

[0067] This embodiment also provides a high-voltage interlock detection method. Figure 7 This is a flowchart of a high-voltage interlock detection method provided in an embodiment of the present invention, referred to as [reference]. Figure 7 The high-voltage interlock detection method includes:

[0068] Step 210: Send a first PWM signal to the PWM signal receiving terminal of the high-voltage interlock circuit through the PWM signal output terminal, so that the triangular wave conversion module of the high-voltage interlock circuit converts the first PWM signal received by the PWM signal receiving terminal into a triangular wave signal according to the signals input by the first detection input terminal and the second detection input terminal; wherein the slope of the triangular wave signal is related to the signals input by the first detection input terminal and the second detection input terminal, and cause the PWM wave conversion module of the high-voltage interlock circuit to generate a second PWM signal according to the triangular wave signal and the set voltage and output it.

[0069] Step 220: Determine the fault type of the interlock circuit of the high-voltage interlock circuit based on the duty cycle of the second PWM signal received at the sampling input terminal.

[0070] The high-voltage interlock detection method of this embodiment can be applied to the high-voltage interlock detection system of any of the above embodiments of the present invention, and has the beneficial effects of the high-voltage interlock detection system of the above embodiments of the present invention.

[0071] Figure 8 This is a flowchart of another high-voltage interlock detection method provided in an embodiment of the present invention, see reference. Figure 8 The high-voltage interlock detection method includes:

[0072] Step 310: A first PWM signal is sent to the PWM signal receiving terminal of the high-voltage interlock circuit via the PWM signal output, so that the triangular wave conversion module of the high-voltage interlock circuit converts the first PWM signal received by the PWM signal receiving terminal into a triangular wave signal according to the signals input to the first detection input terminal and the second detection input terminal; wherein the slope of the triangular wave signal is related to the signals input to the first detection input terminal and the second detection input terminal, and the PWM wave conversion module of the high-voltage interlock circuit generates a second PWM signal according to the triangular wave signal and the set voltage and outputs it.

[0073] Step 320: When the duty cycle of the second PWM signal is equal to the first duty cycle, it is determined that there is a disconnection fault in the interlock circuit.

[0074] Step 330: When the duty cycle of the second PWM signal is equal to the second duty cycle, it is determined that there is a short-to-ground fault at the input of the interlock circuit.

[0075] Step 340: When the duty cycle of the second PWM signal is equal to the third duty cycle, it is determined that there is a short power supply fault at the input of the interlock circuit.

[0076] Step 350: When the duty cycle of the second PWM signal is equal to the fourth duty cycle, determine that there is a short ground or short power supply fault at the output of the interlock circuit.

[0077] The first duty cycle, the second duty cycle, the third duty cycle, and the fourth duty cycle are all unequal.

[0078] The high-voltage interlock detection method in this embodiment determines the fault type of the interlock circuit by detecting the duty cycle of the second PWM signal. Compared with the prior art, it does not require an additional port for analog sampling signals, making fault detection of the interlock circuit easier to achieve and reducing the number of microcontroller ports in the diagnostic module.

[0079] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A high-voltage interlock circuit, characterized in that, include: Triangle wave conversion module, PWM wave conversion module and interlocking circuit; The triangular wave conversion module includes a first detection input terminal, a second detection input terminal, a PWM signal receiving terminal, and a triangular wave output terminal. The first detection input terminal is connected to the input terminal of the interlocking circuit, and the second detection input terminal is connected to the output terminal of the interlocking circuit. The triangular wave conversion module is used to convert a first PWM signal received by the PWM signal receiving terminal into a triangular wave signal based on the signals input to the first detection input terminal and the second detection input terminal. The slope of the triangular wave signal is related to the signals input to the first detection input terminal and the second detection input terminal. The input terminal of the PWM wave conversion module is electrically connected to the output terminal of the triangular wave. The output terminal of the PWM wave conversion module serves as the output terminal of the high-voltage interlock circuit. The PWM wave conversion module is used to generate a second PWM signal based on the triangular wave signal and the set voltage and output it to the diagnostic module so that the diagnostic module can determine the fault type of the interlock circuit based on the duty cycle of the second PWM signal.

2. The high-voltage interlock circuit according to claim 1, characterized in that, The triangular wave conversion module includes an integrating circuit; The integrating circuit includes an operational amplifier and an RC circuit. The RC circuit is electrically connected to the non-inverting input terminal and the output terminal of the operational amplifier. The inverting input terminal of the operational amplifier is connected to the PWM signal receiving terminal. The output terminal of the operational amplifier serves as the output terminal of the integrating circuit, and the output terminal of the integrating circuit serves as the triangular wave output terminal. The RC circuit is electrically connected to the first detection input terminal and the second detection input terminal.

3. The high-voltage interlock circuit according to claim 2, characterized in that, The RC circuit includes a first voltage divider circuit and a capacitor feedback branch. The voltage divider output terminal of the first voltage divider branch is electrically connected to the non-inverting input terminal of the operational amplifier. The first terminal of the capacitor feedback branch is connected to the output terminal of the operational amplifier, and the second terminal of the capacitor feedback branch is connected to the inverting input terminal of the operational amplifier. The capacitor feedback branch includes n capacitors connected in series at the first and second ends of the capacitor feedback branch. The first node in the capacitor feedback branch serves as the first detection input terminal, and the second node in the capacitor feedback branch serves as the second detection input terminal. i capacitors are connected in series between the first node and the second node, where 1≤i≤n-1 and i is an integer, and n is an integer greater than or equal to 2.

4. The high-voltage interlock circuit according to claim 3, characterized in that, The capacitor feedback branch includes a first capacitor and a second capacitor connected in series. The first terminal of the first capacitor serves as the first terminal of the capacitor feedback branch. The second terminal of the first capacitor is electrically connected to the first terminal of the second capacitor. The second terminal of the second capacitor serves as the second terminal of the capacitor feedback branch. The second end of the first capacitor serves as the first node, and the second end of the second capacitor serves as the second node.

5. The high-voltage interlock circuit according to claim 3, characterized in that, The first voltage divider circuit includes a first resistor and a second resistor, which are connected in series between the power input terminal and the ground terminal, and the common terminal of the first resistor and the second resistor is connected to the voltage divider output terminal.

6. The high-voltage interlock circuit according to claim 1, characterized in that, The PWM wave conversion module includes a comparator and a second voltage divider circuit. The non-inverting input terminal of the comparator serves as the input terminal of the PWM wave conversion module, and the inverting input terminal of the comparator is electrically connected to the output terminal of the second voltage divider circuit. The output terminal of the comparator serves as the output terminal of the PWM wave conversion module. The second voltage divider circuit is used to generate the set voltage.

7. The high-voltage interlock circuit according to claim 1, characterized in that, The interlock circuit includes multiple high-voltage electrical components, each of which is connected in series between the input terminal and the output terminal of the interlock circuit.

8. A high-voltage interlocking system, characterized in that, The circuit includes the high-voltage interlock circuit according to any one of claims 1-7, and further includes a diagnostic module; The PWM signal output terminal of the diagnostic module is electrically connected to the PWM signal receiving terminal of the high-voltage interlock circuit, and the sampling input terminal of the diagnostic module is electrically connected to the output terminal of the high-voltage interlock circuit. The diagnostic module is used to output a first PWM signal to the PWM signal receiving terminal through the PWM signal output terminal, and to receive a second PWM signal output by the high-voltage interlock circuit through the sampling input terminal, and to determine the fault type of the interlock circuit according to the duty cycle of the second PWM signal.

9. A high-voltage interlock detection method, characterized in that, include: A first PWM signal is sent from the PWM signal output terminal to the PWM signal receiving terminal of the high-voltage interlock circuit, so that the triangular wave conversion module of the high-voltage interlock circuit converts the first PWM signal received by the PWM signal receiving terminal into a triangular wave signal according to the signals input from the first detection input terminal and the second detection input terminal; wherein the slope of the triangular wave signal is related to the signals input from the first detection input terminal and the second detection input terminal, and the PWM wave conversion module of the high-voltage interlock circuit generates a second PWM signal according to the triangular wave signal and the set voltage and outputs it. The fault type of the interlock circuit of the high-voltage interlock circuit is determined based on the duty cycle of the second PWM signal received at the sampling input terminal.

10. The high-voltage interlock detection method according to claim 9, characterized in that, The step of determining the fault type of the interlock circuit of the high-voltage interlock circuit based on the duty cycle of the second PWM signal received at the sampling input terminal includes: When the duty cycle of the second PWM signal is equal to the first duty cycle, it is determined that there is a disconnection fault in the interlock circuit; When the duty cycle of the second PWM signal is equal to the second duty cycle, it is determined that there is a short-to-ground fault at the input of the interlock circuit; When the duty cycle of the second PWM signal is equal to the third duty cycle, it is determined that there is a short power supply fault at the input of the interlock circuit; When the duty cycle of the second PWM signal is equal to the fourth duty cycle, it is determined that there is a short ground or short power supply fault at the output of the interlock circuit. The first duty cycle, the second duty cycle, the third duty cycle, and the fourth duty cycle are all unequal.

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