Detection system of high-voltage direct-current bus and vehicle

Abstract

The invention provides a detection system of a high-voltage direct-current bus and a vehicle, and relates to the technical field of voltage detection, and the system comprises a sampling circuit, a pulse signal generation circuit, an isolation transmission circuit and a control circuit. The sampling circuit is connected with the positive electrode and the negative electrode of the high-voltage direct-current bus and outputs sampling voltage. The first end of the pulse signal generation circuit is connected with the third end of the sampling circuit, and the pulse signal generation circuit generates a pulse signal based on the sampling voltage; the input side of the isolation transmission circuit is connected with the second end of the pulse signal generation circuit, and the isolation transmission circuit receives the pulse signal; the control circuit is connected with the output side of the isolation transmission circuit, and the control circuit determines the bus voltage of the high-voltage direct-current bus based on the pulse signal. According to the system, the sampling voltage in an analog form is converted into the pulse signal through the pulse signal generation circuit, and the pulse signal is output to the control circuit through the isolation transmission circuit, so that the anti-interference capability is relatively high, and the overall use safety of the system is relatively high.

Description

Technical Field

[0001] This application relates to the field of voltage detection technology, and more specifically, to a DC bus detection system and vehicle. Background Technology

[0002] The energy source for electric vehicles is a high-voltage battery, which transmits direct current (DC) to various electrical devices in the vehicle via a high-voltage direct current bus (HV). To ensure power supply reliability, the voltage of the HV bus needs to be monitored.

[0003] In related technologies, non-isolated detection methods are commonly used to detect the voltage of high-voltage DC buses. However, with non-isolated detection, the high-voltage side circuit and the low-voltage side circuit are directly electrically connected, and the voltage of the high-voltage DC bus is directly applied to the low-voltage side circuit, which may damage the low-voltage circuit and pose certain safety hazards. Furthermore, the detection method has weak anti-interference capabilities and low measurement accuracy. Summary of the Invention

[0004] This application provides a detection system and vehicle for high-voltage DC bus, aiming to solve the problems of certain safety hazards, low anti-interference ability and low measurement accuracy when using non-isolated detection in related technologies.

[0005] In a first aspect, a detection system for a high-voltage direct current (HVDC) bus is provided. The detection system includes a sampling circuit, a pulse signal generating circuit, an isolation transmission circuit, and a control circuit. The first terminal of the sampling circuit is connected to the positive terminal of the HVDC bus, and the second terminal of the sampling circuit is connected to the negative terminal of the HVDC bus. The sampling circuit is used to output a sampling voltage. The first terminal of the pulse signal generating circuit is connected to the third terminal of the sampling circuit. The pulse signal generating circuit receives the sampling voltage and generates a pulse signal based on the sampling voltage. The input side of the isolation transmission circuit is connected to the second terminal of the pulse signal generating circuit. The isolation transmission circuit receives the pulse signal output from the isolation transmission circuit and determines the bus voltage of the HVDC bus based on the pulse signal.

[0006] In the detection system provided in this application embodiment, the sampling circuit simultaneously measures the positive and negative terminals of the high-voltage DC bus and calculates the voltage difference between them to output a sampling voltage with high sampling accuracy. Furthermore, when the sampling circuit simultaneously measures the positive and negative terminals of the high-voltage DC bus, common-mode noise is suppressed, resulting in strong anti-interference capability and enabling the output of a stable sampling voltage to the pulse signal generation circuit. Next, the pulse signal generation circuit converts the analog sampling voltage into a pulse signal and transmits this pulse signal to the control circuit through an isolation transmission circuit. Compared to the direct transmission of easily interfered analog voltage signals in traditional technologies, pulse signals have stronger noise immunity, maintaining signal integrity in complex electromagnetic environments and improving the overall reliability and detection accuracy of the system. Furthermore, by introducing an isolation transmission circuit, electrical isolation between the high-voltage side circuit (including the sampling circuit and the pulse signal generation circuit) and the low-voltage side circuit (i.e., the control circuit) is achieved. This design effectively prevents the high voltage of the high-voltage DC bus from being directly conducted to the low-voltage side, thus preventing the risk of damage to low-voltage devices due to overvoltage and ensuring the safe operation of the system. It also meets the insulation requirements between high-voltage and low-voltage circuits, improving the safety and reliability of the entire detection system.

[0007] In conjunction with the first aspect, in some possible implementations, the pulse signal generating circuit includes a voltage divider module, an energy storage module, and a timer; the first terminal of the voltage divider module is connected to a first power supply voltage; the first terminal of the energy storage module is connected to the second terminal of the voltage divider module, and the second terminal of the energy storage module is grounded; the voltage input pin of the timer serves as the first terminal of the pulse signal generating circuit and is connected to the third terminal of the sampling circuit; the output pin of the timer serves as the second terminal of the pulse signal generating circuit and is connected to the input side of the isolation transmission circuit; the discharge pin of the timer is connected to the third terminal of the voltage divider module; and the trigger pin and threshold pin of the timer are connected to the first terminal of the energy storage module and the second terminal of the voltage divider module.

[0008] In the above technical solution, on the one hand, by using a timer, voltage divider module, and energy storage module to construct an oscillation circuit, the analog sampled voltage can be directly converted into a digital pulse signal, improving the signal's anti-interference capability during transmission. On the other hand, by adjusting the internal control reference voltage of the timer through the sampled voltage, precise modulation of the pulse signal frequency or duty cycle is achieved, enhancing the linearity and stability of signal transmission. Furthermore, this circuit has a simple structure, low cost, and is easy to integrate, making it suitable for this high-voltage detection system.

[0009] Combining the first aspect and the above implementation methods, in some possible implementations, the timer includes a first comparator, a first resistor, a second comparator, a second resistor, and a signal processing module; the non-inverting input of the first comparator serves as the threshold pin of the timer, connected to the first terminal of the energy storage module and the second terminal of the voltage divider module; the inverting input of the first comparator serves as the voltage input pin of the timer, connected to the third terminal of the sampling circuit; one end of the first resistor is connected to the inverting input of the first comparator; the inverting input of the second comparator serves as the trigger pin of the timer, connected to the first terminal of the energy storage module and the second terminal of the voltage divider module; the non-inverting input of the second comparator is connected to the other end of the first resistor; one end of the second resistor is connected to the non-inverting input of the second comparator and the other end of the first resistor, and the other end of the second resistor is grounded; the first input of the signal processing module is connected to the output of the first comparator; the second input of the signal processing module is connected to the output of the second comparator; the output of the signal processing module serves as the output pin of the timer, connected to the input side of the isolation transmission circuit.

[0010] In the above technical solution, a dual comparator structure is used, with two independent comparison nodes—the threshold pin and the trigger pin—allowing for flexible adjustment of start and stop conditions, thus improving the flexibility and adaptability of timing control. Secondly, an internal reference voltage is generated through a voltage divider network composed of the first and second resistors, enabling multi-stage voltage comparison without additional external components, simplifying peripheral circuit design and reducing overall cost. This structure allows the timer to output high-precision, high-stability pulse signals based on the sampled voltage.

[0011] Combining the first aspect and the above implementation methods, in some possible implementation methods, the signal processing module includes a flip-flop, a first switch, and an inverter; the reset terminal of the flip-flop serves as the first input terminal of the signal processing module and is connected to the output terminal of the first comparator; the set terminal of the flip-flop serves as the second input terminal of the signal processing module and is connected to the output terminal of the second comparator; the controlled terminal of the first switch is connected to the inverted output terminal of the flip-flop; the first terminal of the first switch serves as the discharge pin of the timer; and the second terminal of the first switch is grounded; the input terminal of the inverter is connected to the inverted output terminal of the flip-flop; and the output terminal of the inverter serves as the output terminal of the signal processing module and is connected to the input side of the isolation transmission circuit.

[0012] In the above technical solution, this solution achieves bistable logic control by introducing a flip-flop, effectively avoiding the false triggering problem caused by comparator output jitter in traditional timers. Simultaneously, by using the first switch directly driven by the output state of the flip-flop, controllability of the discharge path and low power consumption are achieved. The inverter not only improves the stability of the flip-flop's output signal but also enhances its driving capability for external loads. Furthermore, integrating the above logic units into the signal processing module simplifies the overall circuit structure, reduces cost, and improves the overall anti-interference capability and operational reliability of the system.

[0013] In combination with the first aspect and the above implementation methods, in some possible implementation methods, the isolation transmission circuit includes an isolator and a second switch; the input side of the isolator serves as the input side of the isolation transmission circuit and is connected to the second terminal of the pulse signal generating circuit; the controlled terminal of the second switch is connected to the output side of the isolator, the first terminal of the second switch serves as the output side of the isolation transmission circuit, is connected to the control circuit, and is connected to the second power supply voltage, and the second terminal of the second switch is grounded.

[0014] In the above technical solution, the working principle of the isolation transmission circuit is based on signal isolation and pulse replication mechanisms to achieve safe signal transmission from the high-voltage side to the low-voltage control side. On the one hand, the isolator achieves electrical isolation between the input and output, effectively avoiding electrical crosstalk between the high-voltage side and the low-voltage control side, and improving the overall reliability and safety of the system. On the other hand, the second switch is used to accurately reproduce the pulse signal, ensuring the accurate transmission of timing information, enabling the control circuit to accurately obtain the voltage status information of the high-voltage DC bus, thereby realizing closed-loop control or protection functions. In addition, this structure is relatively simple and has high stability.

[0015] In combination with the first aspect and the above implementation methods, in some possible implementation methods, the isolator is an optocoupler isolator, which includes a light-emitting diode and a transistor; the light-emitting diode serves as the input side of the isolator, is connected to the input side of the isolation transmission circuit, and is connected to a first power supply voltage; the transistor serves as the output side of the isolator, is connected to the controlled terminal of the second switch, and is connected to a second power supply voltage.

[0016] In the above technical solution, the switching on and off of the transistor can be controlled by changing the current of the LED. That is, the high and low levels in the pulse signal change the LED's emission state, correspondingly controlling the transistor's on / off state and outputting the corresponding high and low levels to the subsequent circuit (e.g., the control circuit). Optocouplers offer high adjustment flexibility and fast response speed. Furthermore, the LED requires only a small current to drive its emission, resulting in low power consumption. Secondly, in the optocoupler composed of the LED and the transistor, the LED circuit and the transistor circuit are electrically isolated. That is, there is no direct electrical connection between the LED's control circuit and the transistor's load circuit. This effectively prevents damage from the high-voltage side or large current to the subsequent low-voltage side circuit, achieving electrical isolation and improving the lifespan and reliability of the detection system.

[0017] In conjunction with the first aspect and the above implementation methods, in some possible implementation methods, the isolation transmission circuit further includes a third resistor, a fourth resistor, a fifth resistor, and a sixth resistor; one end of the third resistor is connected to the first power supply voltage, and the other end of the third resistor is connected to the positive terminal of the light-emitting diode; one end of the fourth resistor and one end of the fifth resistor are connected to the second power supply voltage; the other end of the fourth resistor is connected to the collector of the transistor; one end of the sixth resistor is connected to the emitter of the transistor and the controlled terminal of the second switch; the other end of the sixth resistor is grounded; and the other end of the fifth resistor is connected to the first terminal of the second switch and the control circuit.

[0018] In the above technical solution, the third, fourth, and sixth resistors are current-limiting resistors. These resistors limit the current to the LEDs and transistors in the isolator, improving their operational reliability. The fifth resistor is a pull-up resistor for the second switch, preventing the control circuit's connection point from being in an uncertain state (e.g., high impedance or floating state), which could lead to false detections in the control circuit. This improves the detection system's anti-interference capability and reduces the impact of external noise on the detection system.

[0019] In combination with the first aspect and the above implementation methods, in some possible implementation methods, the detection system further includes a seventh resistor and a first capacitor; one end of the seventh resistor is connected to the first end of the second switch, and the other end of the seventh resistor is connected to the control circuit; the first plate of the first capacitor is connected to the other end of the seventh resistor and the control circuit, and the second plate of the first capacitor is grounded.

[0020] In the above technical solution, the RC filter formed by the seventh resistor and the first capacitor can filter out high-frequency noise, reduce interference components in the signal output from the first terminal of the second switch, and improve the signal-to-noise ratio by removing noise through the seventh resistor and the first capacitor, reducing electromagnetic interference and making the detection signal easier for the control circuit to receive. Secondly, the seventh resistor and the first capacitor can also smooth the signal input to the control circuit, reducing signal fluctuations and jitter, making the detection signal received by the control circuit more stable. Thus, by placing the seventh resistor and the first capacitor between the first terminal of the second switch and the control circuit, high-frequency noise in the signal can be filtered out, the detection signal stabilized, the signal-to-noise ratio improved, and electromagnetic interference reduced, thereby ensuring the reliability of the signal received by the control circuit, and consequently ensuring the reliability of the bus voltage detection based on this signal.

[0021] In conjunction with the first aspect and the above implementation methods, in some possible implementations, the sampling circuit includes a first sampling module, a second sampling module, an operational amplifier, an eighth resistor, and a ninth resistor; one end of the first sampling module serves as the first terminal of the sampling circuit and is connected to the positive terminal of the high-voltage DC bus; one end of the second sampling module serves as the second terminal of the sampling circuit and is connected to the negative terminal of the high-voltage DC bus; the non-inverting input terminal of the operational amplifier is connected to the other end of the first sampling module, the inverting input terminal of the operational amplifier is connected to the other end of the second sampling module, and the output terminal of the operational amplifier serves as the third terminal of the sampling circuit and is connected to the first terminal of the pulse signal generation circuit; one end of the eighth resistor is connected to the non-inverting input terminal of the operational amplifier and the other end of the first sampling module, and the other end of the eighth resistor is grounded; one end of the ninth resistor is connected to the inverting input terminal of the operational amplifier and the other end of the second sampling module, and the other end of the ninth resistor is grounded.

[0022] In the above technical solution, the first sampling module is used to measure the positive voltage of the high-voltage DC bus, and the second sampling module is used to measure the negative voltage of the high-voltage DC bus. Simultaneously, the first and second sampling modules form a voltage divider network, which divides the voltage between the positive and negative terminals of the high-voltage DC bus, providing a stable intermediate potential, i.e., voltage difference. Compared to acquiring single-ended voltage, acquiring dual-ended voltage through the voltage divider network formed by the first and second sampling modules has higher sampling reliability. Secondly, the high-voltage DC bus is a high-voltage system. The voltage divider resistor network formed by the first and second sampling modules can proportionally attenuate the high voltage to a range that the operational amplifier can handle. This avoids the problem of damage to the operational amplifier caused by directly connecting the high voltage to the operational amplifier, which would affect the accuracy of subsequent measurements. In other words, setting up the first and second sampling modules improves measurement reliability.

[0023] Secondly, this application also provides a vehicle including the detection system described in any of the alternative embodiments of the first aspect, wherein the detection system is connected to a high-voltage DC bus. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of a detection system provided in an embodiment of this application; Figure 2 This is a schematic diagram of the circuit structure of a detection system provided in an embodiment of this application; Figure 3 This is a schematic diagram of the circuit structure of a pulse signal generating circuit provided in an embodiment of this application; Figure 4 This is a schematic diagram of the circuit structure of another detection system provided in an embodiment of this application; Figure 5 This is a schematic diagram of the circuit structure of another detection system provided in the embodiments of this application.

[0025] In the attached figures, the following labels are used: 1. Detection system; 11. Sampling circuit; 111. First sampling module; 112. Second sampling module; 12. Pulse signal generation circuit; 121. Voltage divider module; 122. Energy storage module; 123. Timer; 1231. Signal processing module; 13. Isolation transmission circuit; 14. Control circuit; HV, High Voltage DC Bus; COMP1, First Comparator; COMP2, Second Comparator; R1, First Resistor; R2, Second Resistor; R3, Third Resistor; R4, Fourth Resistor; R5, Fifth Resistor; R6, Sixth Resistor; R7, Seventh Resistor; R8, Eighth Resistor; R9, Ninth Resistor; R10, Tenth Resistor; R11, Eleventh Resistor; R12, Twelfth Resistor; R13, Thirteenth Resistor; RS, Flip-flop; Q1, First Switch; Q2, Second Switch; INV, Inverter; U1, Isolator; U2, Operational Amplifier; C1, First Capacitor; C2, Second Capacitor; C3, Third Capacitor; Vin, Sampling Voltage; CTL, Voltage Input Pin; TH, Threshold Pin; OUT, Output Pin; DIS, Discharge Pin; TR, Trigger Pin; R, Reset Pin; S, Set Pin; Output terminal. Detailed Implementation

[0026] The technical solutions in this application will be clearly and thoroughly described below with reference to the accompanying drawings. In the description of the embodiments of this application, unless otherwise stated, " / " means "or," for example, A / B can mean A or B. "And / or" in the text is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Furthermore, in the description of the embodiments of this application, "multiple" refers to two or more than two.

[0027] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as implying or suggesting relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

[0028] Electric vehicles are increasingly favored by consumers due to their intelligence, low noise, and superior power performance, and are widely used in various fields, replacing traditional gasoline vehicles. Unlike gasoline vehicles, electric vehicles are powered by high-voltage batteries. These batteries transmit DC power to various electrical devices in the vehicle via a high-voltage DC bus, such as the motor drive, air conditioning, and positive temperature coefficient (PTC) heaters. To ensure reliable power supply and prevent damage to electrical equipment caused by excessively high or low voltage on the high-voltage DC bus, it is necessary to monitor the voltage of the high-voltage DC bus.

[0029] Currently, there are two types of high-voltage DC bus voltage detection methods: isolated and non-isolated. Most isolated detection methods in related technologies employ dedicated isolation amplifier chips to electrically isolate the detection circuit and the circuit under test, effectively preventing electrical connection between the high-voltage DC bus and the low-voltage detection circuit. However, isolation amplifiers are relatively expensive, resulting in a high cost for isolated detection solutions, making them unsuitable for cost-sensitive vehicle models, such as low-end vehicles or auxiliary systems.

[0030] In related technologies, non-isolated detection methods for measuring the voltage of high-voltage DC buses do not require expensive isolation amplifier chips, resulting in a simpler circuit structure and lower cost, making them suitable for cost-sensitive vehicle models. However, with non-isolated detection, the high-voltage and low-voltage circuits are directly electrically connected, and the voltage from the high-voltage DC bus is directly applied to the low-voltage circuit, potentially damaging it and posing a safety hazard. Furthermore, the detection process suffers from weak interference resistance and lower measurement accuracy.

[0031] Therefore, this application provides a detection system and vehicle for a high-voltage DC bus. The system converts the analog sampling voltage into a pulse signal through a pulse signal generation circuit and outputs it to the control circuit through an isolation transmission circuit. It has strong anti-interference ability and the overall system has high safety.

[0032] The detection system and vehicle for the high-voltage DC bus provided in this application are described below with reference to the accompanying drawings.

[0033] This application provides a vehicle comprising a high-voltage electrical system and a low-voltage electrical system. The high-voltage electrical system includes a high-voltage battery (e.g., a power battery) to supply power to high-power electrical equipment (e.g., motors, inverters, and other high-voltage components) in the vehicle, enabling it to operate normally. The low-voltage electrical system includes a low-voltage battery (e.g., a 12V battery) and a DC-DC converter (DCDC). The DC-DC converter converts the high-voltage electricity from the high-voltage battery to low-voltage electricity to meet the signal transmission / control requirements of the vehicle; further details are omitted here.

[0034] High-voltage batteries typically supply power to high-power electrical equipment via a high-voltage DC bus. When the voltage of the high-voltage DC bus is too high or too low, it can damage the connected high-power equipment, posing a safety hazard. Therefore, the vehicle provided in this application is also equipped with a differential detection system. This system can accurately detect the voltage of the high-voltage DC bus to determine whether the voltage is normal, thereby ensuring the reliability of the power supply to the electrical equipment.

[0035] In order for the detection system 1 provided in this application to detect the voltage of the high-voltage DC bus HV, in one example, such as Figure 1 As shown, the detection system 1 includes a sampling circuit 11, a pulse signal generation circuit 12, an isolation transmission circuit 13, and a control circuit 14. The first terminal of the sampling circuit 11 is connected to the positive terminal HV+ of the high-voltage DC bus HV, and the second terminal of the sampling circuit 11 is connected to the negative terminal HV- of the high-voltage DC bus HV. The first terminal of the pulse signal generation circuit 12 is connected to the third terminal of the sampling circuit 11. The input side of the isolation transmission circuit 13 is connected to the second terminal of the pulse signal generation circuit 12, and the control circuit 14 is connected to the output side of the isolation transmission circuit 13.

[0036] The sampling circuit 11 is used to output a sampling voltage Vin. Specifically, the first and second terminals of the sampling circuit 11 are connected to the positive terminal HV+ and negative terminal HV- of the high-voltage DC bus HV, respectively, resulting in a voltage difference ΔV between the first and second terminals. The sampling circuit 11 can output a sampling voltage Vin based on this voltage difference ΔV. This sampling voltage Vin is the voltage corresponding to the high-voltage DC bus HV sampled by the sampling circuit 11.

[0037] The pulse signal generating circuit 12 receives the sampled voltage Vin, generates a corresponding pulse signal based on Vin, and then outputs the pulse signal to the isolation transmission circuit 13. The isolation transmission circuit 13 receives the pulse signal and outputs it to the control circuit 14. It can be understood that the preceding circuit of the isolation transmission circuit 13 (i.e., the sampling circuit 11 and the pulse signal generating circuit 12) is the high-voltage side circuit, and the following circuit of the isolation transmission circuit 13 (i.e., the control circuit 14) is the low-voltage side circuit. The isolation transmission circuit 13 electrically isolates the high-voltage side circuit from the low-voltage side circuit, preventing the voltage of the high-voltage DC bus HV from being directly applied to the low-voltage side circuit and causing damage. This ensures the normal operation of the low-voltage side circuit and improves the safety of the detection system 1.

[0038] The control circuit 14 receives the pulse signal output from the isolation transmission circuit 13 and determines the bus voltage of the high voltage DC bus HV based on the pulse signal, thereby realizing the accurate detection of the bus voltage of the high voltage DC bus HV.

[0039] Thus, in the detection system 1 provided in this application embodiment, the sampling circuit 11 simultaneously measures the positive terminal HV+ and the negative terminal HV- of the high-voltage DC bus HV, and calculates the voltage difference ΔV between them to output a sampling voltage Vin with high sampling accuracy, resulting in high measurement precision. Furthermore, when the sampling circuit 11 simultaneously measures the positive terminal HV+ and the negative terminal HV- of the high-voltage DC bus HV, common-mode noise can be suppressed, exhibiting strong anti-interference capability, enabling it to output a stable sampling voltage Vin to the pulse signal generation circuit 12. Next, the pulse signal generation circuit 12 converts the analog sampling voltage Vin into a pulse signal and transmits this pulse signal to the control circuit 14 through the isolation transmission circuit 13. Compared to the direct transmission of easily interfered analog voltage signals in traditional technologies, the pulse signal has stronger anti-noise capability, can maintain signal integrity in complex electromagnetic environments, and improves the overall reliability and detection accuracy of the system. Furthermore, by introducing the isolation transmission circuit 13, electrical isolation is achieved between the high-voltage side circuit (including the sampling circuit 11 and the pulse signal generation circuit 12) and the low-voltage side circuit (i.e., the control circuit 14). This design effectively avoids the direct conduction of high voltage from the high-voltage DC bus HV to the low-voltage side, preventing the risk of damage to low-voltage devices due to overvoltage, ensuring the safe operation of the system, and also meeting the insulation requirements between the high-voltage and low-voltage circuits, thus improving the safety and reliability of the entire detection system 1.

[0040] In order for the pulse signal generating circuit 12 to generate a corresponding pulse signal based on the sampled voltage Vin, in one example, such as Figure 2As shown, the pulse signal generating circuit 12 includes a voltage divider module 121, an energy storage module 122, and a timer 123. The first terminal of the voltage divider module 121 is connected to a first power supply voltage VCC1. The first terminal of the energy storage module 122 is connected to the second terminal of the voltage divider module 121, and the second terminal of the energy storage module 122 is grounded. The voltage input pin of the timer 123 (e.g., ...) Figure 2 The CTL shown is used as the first terminal of the pulse signal generation circuit 12 and connected to the third terminal of the sampling circuit 11. The output pin of the timer 123 (as shown) is... Figure 2 As shown, OUT) serves as the second terminal of the pulse signal generating circuit 12, connected to the input side of the isolation transmission circuit 13, and the discharge pin of timer 123 (as shown) Figure 2 The DIS shown is connected to the third terminal of the voltage divider module 121, and the trigger pin of the timer 123 (as shown) is connected to the third terminal of the voltage divider module 121. Figure 2 As shown in TR) and threshold pins (such as Figure 2 The TH shown is connected to the first end of the energy storage module 122 and the second end of the voltage divider module 121.

[0041] It is worth noting that Timer 123 has a corresponding comparator. The sampled voltage Vin is applied to the reference terminal of the internal comparator of Timer 123 through the voltage input pin CTL, changing its internal threshold level. Specifically, the voltage input pin CTL is CONTROL VOLTAGE, the trigger pin TR is TRIGGER, the discharge pin DIS is DISCHARGE, the threshold pin TH is THRESHOLD, and the output pin OUT is OUTPUT. Timer 123 also has a power supply pin Vcc, a ground pin GND, and a reset input pin RESET.

[0042] In this example, the voltage input pin CTL of timer 123 receives the sampled voltage Vin. Assume that before the first power supply voltage VCC1 is applied, the voltage of the energy storage module 122 (i.e., the voltages of the trigger pin TR and the threshold pin TH) is zero. When the circuit is powered on by the first power supply voltage VCC1, since the voltage of the energy storage module 122 cannot change abruptly, the output pin OUT of timer 123 outputs a high level. At this time, the discharge pin DIS remains in a high-impedance state, and the energy storage module 122 begins charging through the voltage divider module 121. After the voltage of the energy storage module 122 is charged to 1 / 2 of the sampled voltage Vin, timer 123 enters its normal operating cycle. When the voltage of the energy storage module 122 is between 1 / 2 of the sampled voltage Vin and the sampled voltage Vin, the output pin OUT of timer 123 remains high, and the discharge pin DIS remains in a high-impedance state. When the energy storage module 122 continues to charge until its voltage reaches the sampling voltage Vin, and this voltage exceeds the threshold of the threshold pin TH, the output pin OUT goes low, and the discharge pin DIS goes low. At this point, the energy storage module 122 cannot continue charging and instead discharges through the voltage divider module 121 and the discharge pin DIS until its voltage reaches half the sampling voltage Vin.

[0043] It is worth noting that this process is repeated periodically to form a continuous square wave pulse signal, the frequency or duty cycle of which changes linearly or nonlinearly with the magnitude of the sampled voltage Vin, thereby realizing time-domain encoding of analog voltage into pulse signal.

[0044] On the one hand, by using timer 123 and an external energy storage voltage divider network (i.e., voltage divider module 121 and energy storage module 122) to form an oscillation circuit, the analog sampled voltage Vin can be directly converted into a digital pulse signal, improving the anti-interference capability of the signal during transmission. On the other hand, by adjusting the internal control reference voltage of timer 124 through the sampled voltage Vin, precise modulation of the pulse signal frequency or duty cycle is achieved, enhancing the linearity and stability of signal transmission. Furthermore, this circuit has a simple structure, low cost, and is easy to integrate, making it suitable for this high-voltage detection system 1.

[0045] Optionally, the energy storage module 122 can be as follows: Figure 2 The second capacitor C2 shown can be divided by the voltage divider module 121, which may include the tenth resistor R10 and the eleventh resistor R11. Correspondingly, when the voltage of the second capacitor C2 is between 1 / 2 of the sampling voltage Vin and the sampling voltage Vin, the output pin OUT of the timer 123 remains high, and the discharge pin DIS remains high impedance. The second capacitor C2 continues to charge until the voltage reaches the sampling voltage Vin. At this time, the charging time constant can be obtained according to formula (1): τ1=(R10+R11)*C2(1) Where τ1 is the charging time constant, C2 is the capacitance of the second capacitor, R10 is the resistance of the tenth resistor R10, and R11 is the resistance of the eleventh resistor R11.

[0046] During this period, the time it takes for the voltage of the second capacitor C2 to charge from 1 / 2 sampling voltage Vin to the sampling voltage Vin can be obtained according to formula (2): (2) Where t1 is the time to charge from 1 / 2 sampling voltage Vin to sampling voltage Vin, VCC1 is the voltage of the first power supply voltage, and Vin is the voltage of the sampling voltage.

[0047] When the voltage of the second capacitor C2 reaches the sampling voltage Vin, it exceeds the threshold of the threshold pin TH. The output pin OUT then goes low, and the discharge pin DIS goes low. The second capacitor C2 can no longer charge and instead discharges through the eleventh resistor R11 and the discharge pin DIS until the voltage of C2 reaches half the sampling voltage Vin. At this point, the discharge time constant is τ2 = R11 * C2. The discharge time during this period can be obtained from formula (3): (3) Where t2 is the time from the sampling voltage Vin to 1 / 2 of the sampling voltage Vin, and 1 / 2Vin is the voltage division based on the sampling voltage.

[0048] In one example, such as Figure 3As shown, timer 123 includes a first comparator COMP1, a first resistor R1, a second comparator COMP2, a second resistor R2, and a signal processing module 1231. The non-inverting input of the first comparator COMP1 serves as the threshold pin TH of timer 123, connected to the first terminal of energy storage module 122 and the second terminal of voltage divider module 121. The inverting input of the first comparator COMP1 serves as the voltage input pin CTL of timer 123, connected to the third terminal of sampling circuit 11. One end of the first resistor R1 is connected to the inverting input of the first comparator COMP1. The inverting input of the second comparator COMP2 serves as the trigger pin TR of timer 123, connected to the first terminal of energy storage module 122 and the second terminal of voltage divider module 121. The non-inverting input of the second comparator COMP2 is connected to the other end of the first resistor R1. One end of the second resistor R2 is connected to the non-inverting input of the second comparator COMP2 and the other end of the first resistor R1, and the other end of the second resistor R2 is grounded. The first input terminal of the signal processing module 1231 is connected to the output terminal of the first comparator COMP1, the second input terminal of the signal processing module 1231 is connected to the output terminal of the second comparator COMP2, and the output terminal of the signal processing module 1231 serves as the output pin OUT of the timer 123 and is connected to the input side of the isolation transmission circuit 13.

[0049] In this design, the non-inverting input of the first comparator COMP1 serves as the threshold pin TH, used to receive the reference voltage, while its inverting input serves as the voltage input pin CTL, used to acquire the sampled voltage Vin. The first resistor R1 forms part of the voltage divider network and also serves for signal coupling and impedance matching. The inverting input of the second comparator COMP2 serves as the trigger pin TR, used to sense changes in the energy storage voltage of the energy storage module 122. The non-inverting input of the second comparator COMP2 is grounded through the second resistor R2, forming a pull-down path to ensure stable input potential in the absence of external excitation.

[0050] In this example, the timer 123 controls the output state by comparing the input voltage with a set threshold, thereby achieving precise timing control of the charging and discharging process of the energy storage module 122.

[0051] Specifically, when the energy storage module 122 begins charging, its voltage gradually increases. When this voltage reaches the threshold set by the threshold pin TH, the first comparator COMP1 detects a positive differential and outputs a high level. The first input of the signal processing module 1231 is set, and correspondingly, the signal processing module 1231 outputs a first level. Simultaneously, if the energy storage voltage of the energy storage module 122 has not yet reached the trigger threshold, the second comparator COMP2 maintains a low output, not affecting the latching state of the signal processing module 1231. As the energy storage voltage of the energy storage module 122 continues to rise and exceeds the trigger reference point formed by the voltage division of the first resistor R1 and the second resistor R2 (i.e., the voltage corresponding to the trigger pin TR), the output of the second comparator COMP2 flips to a high level, the second input of the signal processing module 1231 is set, and correspondingly, the signal processing module 1231 outputs a second level. The first and second levels are signals with opposite level states, thus completing one complete timing cycle output action. This cycle repeats continuously, forming a self-excited multivibrator, which enables the output of timer 123 to obtain a periodic rectangular pulse signal, achieving accurate and reliable conversion from voltage signal to frequency signal.

[0052] The entire process achieves precise edge detection and level transition control based on a dual comparator architecture, improving timing accuracy and timing stability.

[0053] Thus, by employing a dual comparator structure with two independent comparison nodes—the threshold pin TH and the trigger pin TR—the start and stop conditions can be flexibly adjusted, improving the flexibility and adaptability of timing control. Secondly, an internal reference voltage is generated through a voltage divider network composed of the first resistor R1 and the second resistor R2, enabling multi-stage voltage comparison without additional external components, simplifying peripheral circuit design and reducing overall cost. This structure allows Timer 123 to output a high-precision, high-stability pulse signal based on the sampled voltage Vin.

[0054] In one example, such as Figure 3 As shown, the signal processing module 1231 includes a flip-flop RS, a first switch Q1, and an inverter INV. The reset terminal R of the flip-flop RS serves as the first input terminal of the signal processing module 1231 and is connected to the output terminal of the first comparator COMP1. The set terminal S of the flip-flop RS serves as the second input terminal of the signal processing module 1231 and is connected to the output terminal of the second comparator COMP2. The controlled terminal of the first switch Q1 is connected to the inverted output terminal of the flip-flop RS. Connections. The first terminal of the first switch Q1 serves as the discharge pin DIS of the timer 123, and the second terminal of the first switch Q1 is grounded. The input terminal of the inverter INV is connected to the inverted output terminal of the flip-flop RS, and the output terminal of the inverter INV serves as the output terminal of the signal processing module 1231, and is connected to the input side of the isolation transmission circuit 13.

[0055] In this example, when the sampled voltage Vin received by the voltage input pin CTL rises above the threshold voltage of the threshold pin TH, the first comparator COMP1 outputs a high level, resetting the flip-flop RS, and its inverting output... The voltage level changes to low, thus turning off the first switch Q1. At this time, the discharge pin DIS is in a high-impedance state and no longer discharges to ground. Simultaneously, the inverting output terminal... After passing through the inverter INV, the output is high-level to the output pin OUT, which is then sent to the isolation transmission circuit 13 as the output signal of the signal processing module 1231 to achieve stable signal transmission and electrical isolation.

[0056] When the sampling voltage Vin received by the voltage input pin CTL drops below the trigger voltage of the trigger pin TR, the second comparator COMP2 outputs a high level, setting the flip-flop RS, and its inverting output... The voltage level changes to high, thus turning on the first switch Q1. At this time, the discharge pin DIS is pulled low to ground, enabling the energy storage module 122 to discharge rapidly, thus entering the next timing cycle. During this process, the inverter INV will invert the output terminal... The signal is inverted and output to the output pin OUT to ensure that the output signal is synchronized with the discharge action and has good driving capability.

[0057] Thus, this solution effectively avoids the false triggering problem caused by comparator output jitter in traditional timers by introducing a flip-flop RS to achieve bistable logic control. Simultaneously, by using the first switch Q1 directly driven by the output state of the flip-flop RS, controllability of the discharge path and low power consumption are achieved. The inverter INV not only improves the stability of the flip-flop RS output signal but also enhances its ability to drive external loads. Furthermore, integrating the above logic units into the signal processing module 1231 simplifies the overall circuit structure, reduces cost, and improves the overall anti-interference capability and operational reliability of the system.

[0058] Optionally, the first switch Q1 can be an N-type metal-oxide-semiconductor (NMOS) field-effect transistor, a P-type metal-oxide-semiconductor (PMOS) field-effect transistor, an insulated gate bipolar transistor (IGBT), a transistor, a relay circuit, or other devices or circuits capable of switching on and off. This application does not impose specific limitations on this.

[0059] In one example, such as Figure 4As shown, the isolation transmission circuit 13 includes an isolator U1 and a second switch Q2. The input side of the isolator U1 serves as the input side of the isolation transmission circuit 13 and is connected to the second terminal of the pulse signal generating circuit 12. The controlled terminal of the second switch Q2 is connected to the output side of the isolator U1, the first terminal of the second switch Q2 serves as the output side of the isolation transmission circuit 13, is connected to the control circuit 14, and is connected to the second power supply voltage VCC2. The second terminal of the second switch Q2 is grounded.

[0060] Understandably, the pulse signal output by the pulse signal generation circuit 12 is used to control the on / off state of the second switch Q2. That is, the first terminal of the second switch Q2 will "copy" the timing characteristics of the input pulse signal, for example, it will appear as a pulse waveform synchronized with the received pulse signal. This pulse waveform is transmitted to the control circuit 14, which detects parameters such as the frequency, period, or duty cycle of the pulse waveform, and then calculates the bus voltage value of the high voltage DC bus HV.

[0061] In this example, the isolation transmission circuit 13 operates based on a signal isolation and pulse replication mechanism to achieve safe signal transmission from the high-voltage side to the low-voltage control side. On one hand, the isolator U1 achieves electrical isolation between the input and output, effectively avoiding electrical crosstalk between the high-voltage side and the low-voltage control side, thus improving the overall reliability and safety of the system. On the other hand, the second switch Q2 accurately reproduces the pulse signal, ensuring accurate transmission of timing information, enabling the control circuit 14 to accurately acquire the voltage status information of the high-voltage DC bus HV, thereby achieving closed-loop control or protection functions. Furthermore, this structure is relatively simple and highly stable.

[0062] Optionally, the second switch Q2 can be an NMOS field-effect transistor, a PMOS field-effect transistor, an IGBT, a transistor, a relay circuit, or other devices or circuits capable of switching on and off. This application does not impose specific limitations on this.

[0063] In one example, such as Figure 4 As shown, isolator U1 is an optocoupler isolator, which includes a light-emitting diode (LED) and a transistor. The LED serves as the input side of isolator U1, connected to the input side of the isolation transmission circuit 13, and is connected to the first power supply voltage VCC1. The transistor serves as the output side of isolator U1, connected to the controlled terminal of the second switch Q2, and is connected to the second power supply voltage VCC2.

[0064] In this example, the switching on and off of the transistor can be controlled by changing the current of the LED. That is, the high and low levels in the pulse signal change the LED's emission state, correspondingly controlling the transistor's on / off state, and outputting the corresponding high and low levels to the subsequent circuit (e.g., control circuit 14). Optocouplers offer high adjustment flexibility and fast response speed. Furthermore, the LED requires only a small current to drive it, resulting in low power consumption. Secondly, in the optocoupler composed of an LED and a transistor, the LED circuit and the transistor circuit are electrically isolated. That is, there is no direct electrical connection between the LED's control circuit and the transistor's load circuit. This effectively prevents damage from high-voltage or high-current conditions to the subsequent low-voltage circuit, achieving electrical isolation and improving the lifespan and reliability of the detection system.

[0065] Alternatively, the isolator U1 may also be selected from other devices or circuits that can achieve the above functions, and this application does not impose specific restrictions on this.

[0066] In one example, please refer to Figure 4 and Figure 5 As shown, the isolation transmission circuit 13 also includes a third resistor R3, a fourth resistor R4, a fifth resistor R5, and a sixth resistor R6. One end of the third resistor R3 is connected to the first power supply voltage VCC1, and the other end of the third resistor R3 is connected to the positive terminal of the light-emitting diode. One end of the fourth resistor R4 and one end of the fifth resistor R5 are connected to the second power supply voltage VCC2. The other end of the fourth resistor R4 is connected to the collector of the transistor. One end of the sixth resistor R6 is connected to the emitter of the transistor and the controlled terminal of the second switch Q2, and the other end of the sixth resistor R6 is grounded. The other end of the fifth resistor R5 is connected to the first terminal of the second switch Q2 and the control circuit 14.

[0067] In this example, the third resistor R3, the fourth resistor R4, and the sixth resistor R6 are current-limiting resistors. These resistors limit the current to the LEDs and transistors in the isolator, improving their operational reliability. The fifth resistor R5 is the pull-up resistor for the second switch Q2. This prevents the connection point of the control circuit 14 from being in an uncertain state (e.g., a high-impedance state or a floating state), which could lead to false detections in the control circuit 14. This improves the anti-interference capability of the detection system 1 and reduces the impact of external noise on the detection system 1.

[0068] In one example, please refer to Figure 4 and Figure 5As shown, the detection system 1 also includes a seventh resistor R7 and a first capacitor C1; one end of the seventh resistor R7 is connected to the first end of the second switch Q2, and the other end of the seventh resistor R7 is connected to the control circuit 14; the first plate of the first capacitor C1 is connected to the other end of the seventh resistor R7 and the control circuit 14, and the second plate of the first capacitor C1 is grounded.

[0069] In this example, the RC filter formed by the seventh resistor R7 and the first capacitor C1 can filter out high-frequency noise, reduce interference components in the signal output from the first terminal of the second switch Q2, and improve the signal-to-noise ratio by removing noise through the seventh resistor R7 and the first capacitor C1, reducing electromagnetic interference and making the detection signal easier for the control circuit 14 to receive. Secondly, the seventh resistor R7 and the first capacitor C1 can also smooth the signal input to the control circuit 14, reducing signal fluctuations and jitter, making the detection signal received by the control circuit 14 more stable. Thus, by placing the seventh resistor R7 and the first capacitor C1 between the first terminal of the second switch Q2 and the control circuit 14, high-frequency noise in the signal can be filtered out, the detection signal stabilized, the signal-to-noise ratio improved, and electromagnetic interference reduced, thereby ensuring the reliability of the signal received by the control circuit 14, and consequently ensuring the reliability of the bus voltage detection based on this signal.

[0070] In order for the sampling circuit 11 provided in this application to simultaneously sample the positive terminal HV+ and the negative terminal HV- of the high-voltage DC bus HV, in one example, such as Figure 5 As shown, the sampling circuit 11 includes a first sampling module 111, a second sampling module 112, an operational amplifier U2, an eighth resistor R8, and a ninth resistor R9. One end of the first sampling module 111 serves as the first terminal of the sampling circuit 11 and is connected to the positive terminal of the high-voltage DC bus HV; one end of the second sampling module 112 serves as the second terminal of the sampling circuit 11 and is connected to the negative terminal of the high-voltage DC bus HV; the non-inverting input terminal of the operational amplifier U2 is connected to the other end of the first sampling module 111, the inverting input terminal of the operational amplifier U2 is connected to the other end of the second sampling module 112, and the output terminal of the operational amplifier U2 serves as the third terminal of the sampling circuit 11 and is connected to the first terminal of the pulse signal generation circuit 12; one end of the eighth resistor R8 is connected to the non-inverting input terminal of the operational amplifier U2 and the other end of the first sampling module 111, and the other end of the eighth resistor R8 is grounded; one end of the ninth resistor R9 is connected to the inverting input terminal of the operational amplifier U2 and the other end of the second sampling module 112, and the other end of the ninth resistor R9 is grounded.

[0071] In this example, the first sampling module 111 measures the positive terminal HV+ voltage of the high-voltage DC bus HV, and the second sampling module 112 measures the negative terminal HV- voltage of the high-voltage DC bus HV. Simultaneously, the first sampling module 111 and the second sampling module 112 form a voltage divider network, which divides the voltage between the positive terminal HV+ and the negative terminal HV- of the high-voltage DC bus HV, providing a stable intermediate potential, i.e., the voltage difference ΔV. Compared to acquiring single-ended voltage, acquiring dual-ended voltage through the voltage divider network formed by the first sampling module 111 and the second sampling module 112 has higher sampling reliability. Secondly, since the high-voltage DC bus HV is a high-voltage system, the voltage divider resistor network formed by the first sampling module 111 and the second sampling module 112 can proportionally attenuate the high voltage to a range that the operational amplifier U2 can handle. This avoids the problem of damage to the operational amplifier U2 when directly connected to high voltage, which would affect the accuracy of subsequent measurements. In other words, setting up the first sampling module 111 and the second sampling module 112 improves measurement reliability.

[0072] After the operational amplifier U2 is connected to the voltage difference ΔV between the first sampling module 111 and the second sampling module 112, it is amplified and converted into a single-ended voltage (i.e., the sampling voltage Vin), and then output to the pulse signal generation circuit 12 to improve the reliability of the signal connected to the pulse signal generation circuit 12.

[0073] Optional, such as Figure 5 As shown, the first sampling module 111 includes multiple twelfth resistors R12 connected in series. The end of the first twelfth resistor R12 not connected to any other resistor serves as one end of the first sampling module 111 and is connected to the positive terminal of the high-voltage DC bus HV. The end of the last twelfth resistor R12 not connected to any other resistor serves as the other end of the first sampling module 111, connected to the non-inverting input terminal of the operational amplifier U2 and one end of the first resistor R1. The multiple twelfth resistors R12 connected in series sample the positive terminal HV+ voltage of the high-voltage DC bus HV. By using these multiple twelfth resistors connected in series, the voltage of the high-voltage DC bus HV can be adjusted proportionally. Furthermore, the circuit structure of the first sampling module 111, composed of multiple twelfth resistors R12 connected in series, is simple, highly reliable, and easy to maintain and debug.

[0074] Optional, such as Figure 5As shown, the second sampling module 112 includes multiple thirteenth resistors R13 connected in series. The end of the first thirteenth resistor R13 not connected to any other resistor serves as one end of the second sampling module 112 and is connected to the negative terminal of the high-voltage DC bus HV. The end of the last thirteenth resistor R13 not connected to any other resistor serves as the other end of the second sampling module 112, connected to the inverting input terminal of operational amplifier U2 and one end of the second resistor R2. The multiple thirteenth resistors R13 connected in series sample the negative terminal HV- voltage of the high-voltage DC bus HV, allowing for precise adjustment of the high-voltage DC bus HV voltage. Furthermore, the circuit structure of the second sampling module 112, composed of multiple thirteenth resistors R13 connected in series, is simple, highly reliable, and easy to maintain and debug.

[0075] To ensure the sampling synchronization of the first sampling module 111 and the second sampling module 112, the twelfth resistor R12 and the thirteenth resistor R13 are set in the same number. For example, as shown below... Figure 5 As shown, the first sampling module 111 in this application is provided with three twelfth resistors R12, and the second sampling module 112 is provided with three thirteenth resistors R13. It should be noted that the first sampling module 111 and the second sampling module 112 may also include other numbers of twelfth resistors R12 and thirteenth resistors R13; this application does not impose specific limitations on this. This application only uses the example of sampling circuit 11 including three twelfth resistors R12 and three thirteenth resistors R13 connected in series for illustration.

[0076] When the sampling circuit 11 includes three twelfth resistors R12 and three thirteenth resistors R13 connected in series, such as Figure 5 As shown, the voltage difference ΔV is the voltage difference between nodes H and V. By setting the ninth resistor R9, the operational amplifier U2 has negative feedback. Utilizing the virtual short characteristic of the op-amp, it can be known that the voltages at the non-inverting and inverting input terminals of the operational amplifier U2 are equal. Combining this with the virtual open characteristic of the op-amp, the voltage difference ΔV can be obtained according to formula (4): ΔV=Vhv*(R12+R13) / (R12+R12+R12+R13+R13+R13)(4) Where Vhv is the voltage between the positive terminal HV+ and the negative terminal HV- of the high-voltage DC bus HV, R12 in (R12+R13) is the resistance value of the twelfth resistor connected to the non-inverting input terminal of operational amplifier U2, R13 is the resistance value of the thirteenth resistor connected to the inverting input terminal of operational amplifier U2, and R12 in (R12+R12+R12+R13+R13+R13) is the resistance value of each twelfth resistor connected in series, and R13 is the resistance value of each thirteenth resistor connected in series.

[0077] If the resistance value of the twelfth resistor R12 connected to the non-inverting input terminal of operational amplifier U2 is set to be equal to the resistance value of the thirteenth resistor R13 connected to the inverting input terminal of operational amplifier U2, then formula (5) can be obtained: Vin = ΔV (5) Wherein, Vin is the voltage of the sampled voltage.

[0078] Thus, the voltage difference ΔV at the input of operational amplifier U2 is equal to the sampling voltage Vin at the output of operational amplifier U2.

[0079] To improve the reliability of the sampling voltage Vin output from operational amplifier U2 to pulse signal generation circuit 12, in one example, such as Figure 5 As shown, the detection system 1 also includes a third capacitor C3. The first plate of the third capacitor C3 is connected to one end of the ninth resistor R9, the output terminal of the operational amplifier U2, and the first terminal of the pulse signal generation circuit 12. The second plate of the third capacitor C3 is connected to the operational amplifier U2 and the negative terminal HV- of the high-voltage DC bus HV, which are grounded together.

[0080] In this example, the third capacitor C3 can filter the sampling voltage Vin output by the operational amplifier U2 to filter out high-frequency spike pulses in the circuit, prevent the circuit from oscillating, and improve the integrity and accuracy of the sampling voltage Vin output to the pulse signal generation circuit 12, thereby improving the detection reliability of the subsequent circuits and the detection system 1.

[0081] In summary, in the detection system 1 provided in this application embodiment, the sampling circuit 11 simultaneously measures the positive terminal HV+ and the negative terminal HV- of the high-voltage DC bus HV, and calculates the voltage difference ΔV between them to output a sampling voltage Vin with high sampling accuracy, resulting in high measurement precision. Furthermore, when the sampling circuit 11 simultaneously measures the positive terminal HV+ and the negative terminal HV- of the high-voltage DC bus HV, it can suppress common-mode noise and has strong anti-interference capabilities, enabling it to output a stable sampling voltage Vin to the pulse signal generation circuit 12. Next, the pulse signal generation circuit 12 converts the analog sampling voltage Vin into a pulse signal and transmits this pulse signal to the control circuit 14 through the isolation transmission circuit 13. Compared to the direct transmission of easily interfered analog voltage signals in traditional technologies, the pulse signal has stronger anti-noise capabilities, can maintain signal integrity in complex electromagnetic environments, and improves the overall reliability and detection accuracy of the system. Furthermore, by introducing the isolation transmission circuit 13, electrical isolation is achieved between the high-voltage side circuit (including the sampling circuit 11 and the pulse signal generation circuit 12) and the low-voltage side circuit (i.e., the control circuit 14). This design effectively avoids the direct conduction of high voltage from the high-voltage DC bus HV to the low-voltage side, preventing the risk of damage to low-voltage devices due to overvoltage, ensuring the safe operation of the system, and also meeting the insulation requirements between the high-voltage and low-voltage circuits, thus improving the safety and reliability of the entire detection system 1.

[0082] Through the above description of the embodiments, those skilled in the art will understand that, for the sake of convenience and brevity, only the division of the above functional modules is used as an example. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0083] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another device, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0084] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A detection system for a high-voltage DC bus, characterized in that, The detection system includes: A sampling circuit, wherein the first terminal of the sampling circuit is connected to the positive terminal of the high-voltage DC bus, and the second terminal of the sampling circuit is connected to the negative terminal of the high-voltage DC bus, and the sampling circuit is used to output a sampling voltage; A pulse signal generating circuit, wherein a first terminal of the pulse signal generating circuit is connected to a third terminal of the sampling circuit, the pulse signal generating circuit receives the sampling voltage and generates a pulse signal based on the sampling voltage; An isolated transmission circuit, wherein the input side of the isolated transmission circuit is connected to the second terminal of the pulse signal generating circuit, and the isolated transmission circuit receives the pulse signal; and, A control circuit is connected to the output side of the isolation transmission circuit. The control circuit receives the pulse signal output from the isolation transmission circuit and determines the bus voltage of the high-voltage DC bus based on the pulse signal.

2. The detection system according to claim 1, characterized in that, The pulse signal generating circuit includes: A voltage divider module, wherein the first terminal of the voltage divider module is connected to a first power supply voltage; An energy storage module, wherein a first terminal of the energy storage module is connected to a second terminal of the voltage divider module, and the second terminal of the energy storage module is grounded; and, The timer has its voltage input pin as the first terminal of the pulse signal generation circuit and connected to the third terminal of the sampling circuit. The timer's output pin is the second terminal of the pulse signal generation circuit and connected to the input side of the isolation transmission circuit. The timer's discharge pin is connected to the third terminal of the voltage divider module. The timer's trigger pin and threshold pin are connected to the first terminal of the energy storage module and the second terminal of the voltage divider module.

3. The detection system according to claim 2, characterized in that, The timer includes: The first comparator has its non-inverting input serving as the threshold pin of the timer, connected to the first terminal of the energy storage module and the second terminal of the voltage divider module, and its inverting input serving as the voltage input pin of the timer, connected to the third terminal of the sampling circuit. A first resistor, one end of which is connected to the inverting input terminal of the first comparator; The second comparator has its inverting input terminal serving as the trigger pin of the timer, and is connected to the first terminal of the energy storage module and the second terminal of the voltage divider module. The non-inverting input terminal of the second comparator is connected to the other end of the first resistor. A second resistor, one end of which is connected to the non-inverting input of the second comparator and the other end of the first resistor, and the other end of the second resistor is grounded; and... The signal processing module has a first input terminal connected to the output terminal of the first comparator, a second input terminal connected to the output terminal of the second comparator, and an output terminal serving as the output pin of the timer, connected to the input side of the isolated transmission circuit.

4. The detection system according to claim 3, characterized in that, The signal processing module includes: The trigger has its reset terminal serving as the first input terminal of the signal processing module and connected to the output terminal of the first comparator, and its set terminal serving as the second input terminal of the signal processing module and connected to the output terminal of the second comparator. A first switch, the controlled terminal of the first switch is connected to the inverting output terminal of the trigger, the first terminal of the first switch serves as the discharge pin of the timer, and the second terminal of the first switch is grounded; and, An inverter, the input of which is connected to the inverted output of the flip-flop, and the output of which serves as the output of the signal processing module and is connected to the input side of the isolated transmission circuit.

5. The detection system according to claim 1, characterized in that, The isolated transmission circuit includes: An isolator, wherein the input side of the isolator serves as the input side of the isolated transmission circuit and is connected to the second terminal of the pulse signal generating circuit; and, The second switch has its controlled terminal connected to the output side of the isolator. The first terminal of the second switch serves as the output side of the isolation transmission circuit, is connected to the control circuit, and is connected to the second power supply voltage. The second terminal of the second switch is grounded.

6. The detection system according to claim 5, characterized in that, The isolator is an optocoupler isolator, which includes: A light-emitting diode (LED), which serves as the input side of the isolator, is connected to the input side of the isolated transmission circuit, and is supplied with a first power supply voltage; and, The transistor serves as the output side of the isolator, is connected to the controlled terminal of the second switch, and is connected to the second power supply voltage.

7. The detection system according to claim 6, characterized in that, The isolation transmission circuit also includes a third resistor, a fourth resistor, a fifth resistor, and a sixth resistor; One end of the third resistor is connected to the first power supply voltage, and the other end of the third resistor is connected to the positive terminal of the light-emitting diode. One end of the fourth resistor and one end of the fifth resistor are connected to the second power supply voltage. The other end of the fourth resistor is connected to the collector of the transistor. One end of the sixth resistor is connected to the emitter of the transistor and the controlled terminal of the second switch. The other end of the sixth resistor is grounded. The other end of the fifth resistor is connected to the first terminal of the second switch and the control circuit.

8. The detection system according to claim 6, characterized in that, The detection system also includes: A seventh resistor, one end of which is connected to the first terminal of the second switch, and the other end of which is connected to the control circuit; and, The first capacitor has its first plate connected to the other end of the seventh resistor and the control circuit, and its second plate is grounded.

9. The detection system according to any one of claims 1-8, characterized in that, The sampling circuit includes: The first sampling module, one end of which serves as the first terminal of the sampling circuit, is connected to the positive terminal of the high-voltage DC bus. The second sampling module, one end of which serves as the second terminal of the sampling circuit, is connected to the negative terminal of the high-voltage DC bus. An operational amplifier is provided, wherein the non-inverting input terminal of the operational amplifier is connected to the other end of the first sampling module, the inverting input terminal of the operational amplifier is connected to the other end of the second sampling module, and the output terminal of the operational amplifier serves as the third terminal of the sampling circuit and is connected to the first terminal of the pulse signal generation circuit. An eighth resistor, one end of which is connected to the non-inverting input of the operational amplifier and the other end of the first sampling module, and the other end of which is grounded; and, The ninth resistor has one end connected to the inverting input of the operational amplifier and the other end of the second sampling module, and the other end of the ninth resistor is grounded.

10. A vehicle, characterized in that, The vehicles include: The detection system according to any one of claims 1 to 9, wherein the detection system is connected to a high-voltage DC bus.

Images