An isolated detection system and vehicle

Abstract

The application provides an isolated detection system and a vehicle. The isolated detection system comprises a power supply circuit, a signal input circuit, an isolation circuit and a signal processing circuit. The power supply circuit is configured to output a first low-voltage power supply. The signal input circuit is connected to a positive electrode of a high-voltage DC bus, a negative electrode of the high-voltage DC bus and the power supply circuit. The isolation circuit is connected to the signal input circuit and the power supply circuit. The signal processing circuit is connected to the isolation circuit and configured to determine the voltage of the high-voltage DC bus based on the output current of the isolation circuit. The system can directly convert the high-voltage power supply of the high-voltage DC bus into a low-voltage power supply and output the low-voltage power supply to the high-voltage side circuit through the power supply circuit, so that the high-voltage side circuit can work normally, the power supply cost is low, the high-voltage side power supply and the low-voltage side power supply are isolated from each other, the power supply stability is high, the use reliability of each device in the system is improved, and the detection and operation reliability of the system are improved.

Description

Technical Field

[0001] This application relates to the field of voltage detection technology, and more specifically, to an isolation detection system and a 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] When related technologies detect the voltage of the high-voltage DC bus, there are differences between the high-voltage side circuit and the low-voltage side circuit. When powered by the same power source, additional conversion devices are required, which increases costs and reduces power supply stability, resulting in low overall system reliability. Utility Model Content

[0004] This application provides an isolation detection system and vehicle, which aims to solve the problems of low power supply stability and high cost when supplying power to the high-voltage side circuit and the low-voltage side circuit in related technologies.

[0005] In a first aspect, an isolation detection system is provided, comprising a power supply circuit, a signal input circuit, an isolation circuit, and a signal processing circuit; the first terminal of the power supply circuit is connected to the positive terminal of a high-voltage DC bus, the second terminal of the power supply circuit is grounded, and the third terminal of the power supply circuit is used to output a first low-voltage power supply; the first terminal of the signal input circuit is connected to the positive terminal of the high-voltage DC bus and the first terminal of the power supply circuit, the second terminal of the signal input circuit is connected to the negative terminal of the high-voltage DC bus, and the third terminal of the signal input circuit is connected to the third terminal of the power supply circuit to access the first low-voltage power supply; the first terminal of the isolation circuit is connected to the fourth terminal of the signal input circuit, the second terminal of the isolation circuit is connected to the fifth terminal of the signal input circuit, and the third terminal of the isolation circuit is connected to the third terminal of the power supply circuit to access the first low-voltage power supply; the signal processing circuit is connected to the isolation circuit and is used to determine the voltage of the high-voltage DC bus based on the output current of the isolation circuit.

[0006] In the above technical solution, the power supply circuit of this application can directly convert the high-voltage electricity from the high-voltage DC bus into a first low-voltage power supply and output it to the signal input circuit on the high-voltage side, enabling the signal input circuit to operate normally based on this first low-voltage power supply. That is, the high-voltage side circuit in this application can be directly powered by the high-voltage DC bus without the need for additional conversion devices, resulting in lower power supply costs. Furthermore, the high-voltage side power supply and the low-voltage side power supply are mutually isolated, avoiding the possibility that the high-voltage side circuit might conduct high voltage to the low-voltage side circuit through the power line, causing damage to the low-voltage side circuit and posing a significant safety hazard. This results in higher power supply stability, thereby improving the reliability of each component in the system and ensuring the operational reliability of the isolation detection system. Moreover, the isolation detection system provided by this application can reliably detect the voltage of the high-voltage DC bus, promptly identifying voltage anomalies, allowing subsequent operators to take appropriate remedial measures based on the anomaly, thus ensuring the stable operation of the vehicle. Secondly, by setting up an isolation circuit, electrical isolation between the high-voltage side circuit and the low-voltage side circuit can be achieved, so as to avoid the voltage of the high-voltage DC bus being directly applied to the low-voltage side circuit, which would cause damage to the low-voltage side circuit. While ensuring that the low-voltage side circuit can be used normally, the overall safety of the system is improved, thereby further ensuring the detection reliability of the system.

[0007] In conjunction with the first aspect, the power supply circuit includes a current limiting module and a Zener diode; one end of the current limiting module serves as the first terminal of the power supply circuit and is connected to the positive terminal of the high-voltage DC bus; the negative terminal of the Zener diode serves as the third terminal of the power supply circuit and is connected to the third terminal of the signal input circuit and the other end of the current limiting module; the positive terminal of the Zener diode serves as the second terminal of the power supply circuit and is grounded.

[0008] In the above technical solution, the breakdown voltage of the Zener diode is set to be equal to the power supply voltage of the signal input circuit, i.e., the first low-voltage power supply. When the node voltage between the negative terminal of the Zener diode and the other end of the current limiting module reaches the regulated value (note that this regulated value refers to the breakdown voltage of the Zener diode), the Zener diode conducts, stabilizing the node voltage at the breakdown voltage, thereby outputting the first low-voltage power supply to the signal input circuit, enabling the signal input circuit to operate normally based on this first low-voltage power supply. Secondly, if the voltage of the high-voltage DC bus is too high, to prevent excessive current from being input to the Zener diode and causing it to burn out, the current limiting module can effectively limit the maximum current flowing into the Zener diode, thereby protecting the Zener diode and ensuring its normal operation and reliable voltage regulation. Furthermore, compared to transformers and other conversion devices, the Zener diode is smaller in size and lower in cost.

[0009] Combining the first aspect and the above implementation method, the current limiting module includes multiple first resistors connected in series; the end of the first resistor located at the first position that is not connected to the first resistor serves as one end of the current limiting module and is connected to the positive terminal of the high-voltage DC bus; the end of the first resistor located at the last position that is not connected to the first resistor serves as the other end of the current limiting module and is connected to the negative terminal of the Zener diode and the third terminal of the signal input circuit.

[0010] In the aforementioned technical solutions, when the current in the circuit is too high, a single resistor may fail due to overheating. This application uses multiple first resistors connected in series to limit the current flowing to the Zener diode, which can distribute heat, reduce the power load on each resistor, and thus reduce the risk of damage due to overheating, thereby improving the reliability of the first resistors and the safety of the entire circuit. Secondly, by adjusting the ratio of the multiple first resistors, the current flowing through the Zener diode can be controlled more flexibly and precisely to ensure the reliability of the Zener diode.

[0011] Combining the first aspect and the above implementation, the signal input circuit includes a voltage divider module and a first operational amplifier; the first terminal of the voltage divider module serves as the first terminal of the signal input circuit, connected to the positive terminal of the high-voltage DC bus and one terminal of the current limiting module; the second terminal of the voltage divider module serves as the second terminal of the signal input circuit and is connected to the negative terminal of the high-voltage DC bus; the power input terminal of the first operational amplifier serves as the third terminal of the signal input circuit, connected to the negative terminal of the Zener diode and the other terminal of the current limiting module; the non-inverting input terminal of the first operational amplifier is connected to the third terminal of the voltage divider module; the inverting input terminal of the first operational amplifier serves as the fifth terminal of the signal input circuit, connected to the second terminal of the isolation circuit and the fourth terminal of the voltage divider module; and the output terminal of the first operational amplifier serves as the fourth terminal of the signal input circuit and is connected to the first terminal of the isolation circuit.

[0012] In the above technical solution, the voltage divider module outputs the first output voltage obtained from the voltage division process to the subsequent circuit (e.g., the first operational amplifier). The voltage divider module reduces the high voltage of the high-voltage DC bus to a range suitable for the first operational amplifier, thus avoiding damage to the first operational amplifier and affecting measurement accuracy when the high voltage is directly connected. In other words, by setting up the voltage divider module, measurement accuracy can be improved, ensuring the reliability of the signal input circuit. The first operational amplifier acts as a buffer circuit, converting the high-impedance signal (i.e., the first output voltage) into a low-impedance signal, thereby achieving good impedance matching. Furthermore, the first operational amplifier can amplify the first output voltage before outputting it to the isolation circuit, improving the reliability of the signal connected to the isolation circuit.

[0013] Combining the first aspect and the above implementation method, the voltage divider module includes multiple second resistors, third resistors, and fourth resistors connected in series; the end of the first second resistor that is not connected to the second resistor serves as the first end of the voltage divider module, connected to the positive terminal of the high-voltage DC bus and one end of the current limiting module; the end of the last second resistor that is not connected to the second resistor serves as the third end of the voltage divider module, connected to one end of the third resistor and the non-inverting input terminal of the first operational amplifier; the other end of the third resistor serves as the second end of the voltage divider module, connected to the negative terminal of the high-voltage DC bus and one end of the fourth resistor; the other end of the fourth resistor serves as the fourth end of the voltage divider module and is connected to the inverting input terminal of the first operational amplifier.

[0014] In the above technical solution, multiple resistors connected in series are used to divide the voltage of the high-voltage DC bus. By reasonably selecting the resistance values ​​of each resistor, the voltage of the high-voltage DC bus can be accurately converted into a low voltage (i.e., the first output voltage) suitable for measurement or control. The voltage division accuracy is high, the cost is low, the failure rate is low, the voltage division reliability of the voltage divider module is improved, and it is also convenient to locate the fault and replace the damaged components in case of a fault.

[0015] Combining the first aspect and the above implementation method, the isolation circuit is a linear optocoupler, which includes a light-emitting diode, a first photodiode, and a second photodiode; the positive terminal of the light-emitting diode is connected to the fourth terminal of the signal input circuit as the first terminal of the isolation circuit, and the negative terminal of the light-emitting diode is grounded; the positive terminal of the first photodiode is connected to the fifth terminal of the signal input circuit as the second terminal of the isolation circuit, and the negative terminal of the first photodiode is connected to the third terminal of the power supply circuit as the third terminal of the isolation circuit; the second photodiode is connected to the signal processing circuit.

[0016] In the above technical solution, the linear optocoupler transmits information via optical signals, achieving complete electrical isolation between the high-voltage side circuit (i.e., the signal input circuit) and the low-voltage side circuit (i.e., the signal processing circuit), thereby improving the safety of the low-voltage side circuit. Secondly, the linear optocoupler has a fast response time and maintains high linearity between its input and output. This allows the linear optocoupler to provide precise current to the signal processing circuit based on the output of the first operational amplifier, ensuring the accuracy and reliability of the signal processing circuit's detection of the high-voltage DC bus voltage based on this output. Furthermore, compared to dedicated isolation amplifier chips, the linear optocoupler has a lower cost.

[0017] Combining the first aspect and the above implementation method, the signal processing circuit includes a voltage conversion module and a controller; the first terminal of the voltage conversion module is connected to the positive terminal of the second photodiode, and the second terminal of the voltage conversion module is connected to the negative terminal of the second photodiode; the controller is connected to the third terminal of the voltage conversion module.

[0018] In the above technical solution, the voltage conversion module converts the current output by the second photodiode into voltage, enabling the voltage conversion module to output a second output voltage to the controller. The controller then performs a digital-to-analog conversion on the second output voltage to determine the voltage of the high-voltage DC bus. Thus, by converting current into a second output voltage through the voltage conversion module, and then performing a digital-to-analog conversion on the second output voltage by the controller, the corresponding voltage of the high-voltage DC bus can be determined, thereby achieving accurate detection of the high-voltage DC bus voltage.

[0019] Combining the first aspect and the above implementation method, the voltage conversion module includes a second operational amplifier and a fifth resistor; the non-inverting input terminal of the second operational amplifier serves as the first terminal of the voltage conversion module and is connected to the positive terminal of the second photodiode; the power input terminal of the second operational amplifier serves as the second terminal of the voltage conversion module and is connected to the negative terminal of the second photodiode; the output terminal of the second operational amplifier serves as the third terminal of the voltage conversion module and is connected to the controller and the inverting input terminal of the second operational amplifier; one end of the fifth resistor is connected to the non-inverting input terminal of the second operational amplifier, and the other end of the fifth resistor is grounded.

[0020] In the above technical solution, the second operational amplifier is a non-inverting amplifier. Compared with the inverting amplifier, the non-inverting amplifier is suitable for high-impedance signal sources (such as photodiodes) and has better noise performance. In addition, the second operational amplifier can keep its input and output signals in phase, ensuring the reliability of its second output voltage based on the current output.

[0021] Combining the first aspect and the above implementation, the voltage conversion module includes a third operational amplifier, a sixth resistor, and a first capacitor; the non-inverting input of the third operational amplifier serves as the first terminal of the voltage conversion module and is connected to the positive terminal of the second photodiode; the inverting input of the third operational amplifier serves as the second terminal of the voltage conversion module and is connected to the negative terminal of the second photodiode; the output of the third operational amplifier serves as the third terminal of the voltage conversion module and is connected to the controller; one end of the sixth resistor is connected to the inverting input of the third operational amplifier, and the other end of the sixth resistor is connected to the output of the third operational amplifier and the controller; the first plate of the first capacitor is connected to one end of the sixth resistor and the inverting input of the third operational amplifier, and the second plate of the first capacitor is connected to the other end of the sixth resistor, the output of the third operational amplifier, and the controller.

[0022] In the above technical solution, the third operational amplifier is an inverting amplifier. Compared with the non-inverting amplifier, the signal processing of the inverting amplifier is more stable, and it can amplify the signal by inverting it, thus ensuring the reliability of the second output voltage corresponding to the current output.

[0023] Secondly, embodiments of this application provide a vehicle that includes the isolation detection system described in any of the optional embodiments of the first aspect, the isolation detection system being connected to a high-voltage DC bus. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the circuit structure of an isolation detection system provided in an embodiment of this application;

[0025] Figure 2 This is a schematic diagram of the circuit structure of another isolation detection system provided in an embodiment of this application;

[0026] Figure 3 This is a schematic diagram of the circuit structure of another isolation detection system provided in the embodiments of this application;

[0027] Figure 4 This is a schematic diagram of the circuit structure of another isolation detection system provided in the embodiments of this application;

[0028] Figure 5 This is a schematic diagram of the circuit structure of another isolation detection system provided in the embodiments of this application;

[0029] Figure 6 This is a schematic diagram of the circuit structure of another isolation detection system provided in the embodiments of this application;

[0030] Figure 7 This is a schematic diagram of the circuit structure of another isolation detection system provided in the embodiments of this application.

[0031] In this context, the reference numerals are included;

[0032] 1. Isolation detection system; 11. Power supply circuit; 111. Current limiting module; 12. Signal input circuit; 121. Voltage divider module; 13. Isolation circuit; 14. Signal processing circuit; 141. Voltage conversion module; 142. Controller;

[0033] R1, first resistor; R2, second resistor; R3, third resistor; R4, fourth resistor; R5, fifth resistor; R6, sixth resistor; R7, seventh resistor; R8, eighth resistor; U1, first operational amplifier; U2, second operational amplifier; U3, third operational amplifier; U4, linear optocoupler; LED, light-emitting diode; PD1, first photodiode; PD2, second photodiode; C1, first capacitor; C2, second capacitor; Dz1, Zener diode; Dz2, Zener diode; VCC1, first low-voltage power supply; VCC2, second low-voltage power supply; HV, high-voltage DC bus; HV+, positive terminal; HV-, negative terminal; Vin, first output voltage; Vout, second output voltage. Detailed Implementation

[0034] 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.

[0035] 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.

[0036] 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.

[0037] Currently, related technologies typically employ isolated or non-isolated detection circuits to detect the voltage of high-voltage DC buses. Components in both the low-voltage and high-voltage side circuits usually require a low-voltage power supply to operate normally. The low-voltage side circuit is typically powered by a low-voltage battery. However, the high-voltage side circuit differs from the low-voltage side circuit and cannot be directly powered by a low-voltage battery. An additional conversion device is usually required, which is costly. Furthermore, when both the low-voltage and high-voltage side circuits are powered by the same power source, the high-voltage side circuit may conduct high voltage through the power lines to the low-voltage side circuit, causing damage and posing a safety hazard. Additionally, the power supply stability is low, resulting in low overall system reliability and consequently affecting the detection performance of the entire detection circuit, leading to low detection reliability.

[0038] Therefore, this application provides an isolation detection system and a vehicle. This system, through a power supply circuit, can directly convert the high-voltage electricity from the high-voltage DC bus into a first low-voltage power supply, which is then output to the signal input circuit on the high-voltage side, enabling the signal input circuit to operate normally based on this first low-voltage power supply. The power supply cost is low, and the high-voltage and low-voltage power supplies are mutually isolated, resulting in high power supply stability. This improves the reliability of the components in the system, thereby enhancing the system's detection and operational reliability.

[0039] The isolation and detection system and vehicle provided in the embodiments of this application will be described exemplarily below with reference to the accompanying drawings.

[0040] 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 power high-power electrical equipment (e.g., motors, inverters, and other high-voltage components) within the vehicle, enabling normal vehicle operation. 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.

[0041] 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 equipped with an isolation detection system. This system can accurately detect the voltage of the high-voltage DC bus to determine if it is normal, thereby ensuring the reliability of the power supply to the electrical equipment. Simultaneously, the isolation detection system provided in this application is equipped with a high-voltage side power supply. This high-voltage side power supply outputs low-voltage power to the high-voltage side circuit, enabling the devices in the high-voltage side circuit to operate normally without the need for additional transformers or other isolation conversion circuits.

[0042] In one example, such as Figure 1 As shown, the isolation detection system 1 includes a power supply circuit 11, a signal input circuit 12, an isolation circuit 13, and a signal processing circuit 14. The power supply circuit 11, the signal input circuit 12, the isolation circuit 13, and the signal processing circuit 14 are connected in sequence.

[0043] Specifically, the first terminal of power supply circuit 11 is connected to the positive terminal HV+ of the high-voltage DC bus HV, the second terminal of power supply circuit 11 is grounded, and the third terminal of power supply circuit 11 is used to output the first low-voltage power supply VCC1. The first terminal of signal input circuit 12 is connected to the positive terminal HV+ of the high-voltage DC bus HV and the first terminal of power supply circuit 11, the second terminal of signal input circuit 12 is connected to the negative terminal HV- of the high-voltage DC bus HV, and the third terminal of signal input circuit 12 is connected to the third terminal of power supply circuit 11 to access the first low-voltage power supply VCC1. The first terminal of isolation circuit 13 is connected to the fourth terminal of signal input circuit 12, the second terminal of isolation circuit 13 is connected to the fifth terminal of signal input circuit 12, and the third terminal of isolation circuit 13 is connected to the third terminal of power supply circuit 11 to access the first low-voltage power supply VCC1. Signal processing circuit 14 is connected to isolation circuit 13 and is used to determine the voltage of high-voltage DC bus HV based on the output current of isolation circuit 13.

[0044] In this example, the signal input circuit 12 is used to input the voltage of the high-voltage DC bus HV and output it to the isolation circuit 13. The isolation circuit 13 generates a corresponding current based on the signal provided by the signal input circuit 12 and outputs it to the signal processing circuit 14 on the low-voltage side. The signal processing circuit 14 can determine the voltage of the high-voltage DC bus HV based on this current. In this way, the isolation detection system 1 provided by this application can realize the isolation monitoring of the voltage of the high-voltage DC bus HV, and promptly detect abnormal voltage conditions, so that subsequent operators can take corresponding remedial measures based on the abnormal conditions to ensure the stable operation of the vehicle.

[0045] It is worth noting that the pre-stage circuit (i.e., signal input circuit 12) of the isolation circuit 13 is a high-voltage side circuit. The post-stage circuit (i.e., signal processing circuit 14) of the isolation circuit 13 is a low-voltage side circuit. The isolation circuit 13 can electrically isolate the high-voltage side circuit and the low-voltage side circuit to prevent the voltage of the high-voltage DC bus HV from being directly applied to the low-voltage side circuit, which could damage the low-voltage side circuit. This ensures that the low-voltage side circuit can be used normally and improves the safety of the single-sided detection system 1. The low-voltage side circuit can be directly powered by a low-voltage battery. In order for the high-voltage side signal input circuit 12 to work normally, the power supply circuit 11 can directly convert the high-voltage electricity of the high-voltage DC bus HV into a first low-voltage power supply VCC1 and output the first low-voltage power supply VCC1 to the signal input circuit 12, so that the signal input circuit 12 can work normally based on the first low-voltage power supply VCC1.

[0046] Thus, the power supply circuit 11 in this application can directly convert the high-voltage electricity of the high-voltage DC bus HV into a first low-voltage power supply VCC1 and output it to the signal input circuit 12 on the high-voltage side, enabling the signal input circuit 12 to operate normally based on the first low-voltage power supply VCC1. That is, the high-voltage side circuit (i.e., the signal input circuit 12) in this application can be directly powered by the high-voltage DC bus HV without the need for additional conversion devices, resulting in lower power supply costs. Furthermore, the high-voltage side power supply and the low-voltage side power supply are mutually isolated, avoiding the possibility that the high-voltage side circuit might conduct high voltage to the low-voltage side circuit through the power line, causing damage to the low-voltage side circuit and posing a significant safety hazard. This results in higher power supply stability, thereby improving the reliability of each component in the system and ensuring the reliability of the isolation detection system 1. Moreover, the isolation detection system 1 provided in this application can reliably detect the voltage of the high-voltage DC bus HV, promptly identifying voltage anomalies, allowing subsequent operators to take appropriate remedial measures based on the anomaly to ensure stable vehicle operation. Secondly, by setting up the isolation circuit 13, electrical isolation between the high-voltage side circuit and the low-voltage side circuit can be achieved, so as to avoid the voltage of the high-voltage DC bus HV being directly applied to the low-voltage side circuit, which would cause damage to the low-voltage side circuit. While ensuring that the low-voltage side circuit can be used normally, the overall safety of the system is improved, so as to further ensure the detection reliability of the system.

[0047] In one example, such as Figure 2 As shown, the power supply circuit 11 includes a current limiting module 111 and a Zener diode Dz1. One end of the current limiting module 111 serves as the first terminal of the power supply circuit 11 and is connected to the positive terminal HV+ of the high-voltage DC bus HV. The negative terminal of the Zener diode Dz1 serves as the third terminal of the power supply circuit 11 and is connected to the third terminal of the signal input circuit 12 and the other end of the current limiting module 111. The positive terminal of the Zener diode Dz1 serves as the second terminal of the power supply circuit 11 and is grounded.

[0048] In this example, the breakdown voltage of the Zener diode Dz1 is set to be equal to the power supply voltage of the signal input circuit 12, i.e., the first low-voltage power supply VCC1. When the node voltage between the negative terminal of the Zener diode Dz1 and the other end of the current limiting module 111 reaches the regulated value—it is worth noting that the regulated value at this time refers to the breakdown voltage of the Zener diode Dz1—the Zener diode Dz1 conducts, stabilizing the node voltage at the breakdown voltage. This results in the output of the first low-voltage power supply VCC1 to the signal input circuit 12, enabling the signal input circuit 12 to operate normally based on this first low-voltage power supply VCC1. Furthermore, if the voltage of the high-voltage DC bus HV is too high, to prevent excessive current from being input to the Zener diode Dz1 and causing it to burn out, the current limiting module 111 can effectively limit the maximum current flowing into the Zener diode Dz1, thereby protecting the Zener diode Dz1 and ensuring its normal operation and reliable voltage regulation. Secondly, compared to conversion devices such as transformers, the Zener diode Dz1 is smaller in size and lower in cost.

[0049] In one example, such as Figure 3 As shown, the current limiting module 111 includes multiple first resistors R1 connected in series. The end of the first resistor R1 that is not connected to any other first resistor R1 serves as one end of the current limiting module 111 and is connected to the positive terminal HV+ of the high-voltage DC bus HV. The end of the first resistor R1 that is not connected to any other first resistor R1 serves as the other end of the current limiting module 111 and is connected to the negative terminal of the Zener diode Dz1 and the third terminal of the signal input circuit 12.

[0050] When the current in the circuit is too high, a single resistor may fail due to overheating. This application uses a series-connected first resistor R1 to limit the current flowing to the Zener diode Dz1, which can distribute heat, reduce the power load on each resistor, and thus reduce the risk of damage due to overheating, thereby improving the reliability of the first resistor R1 and the safety of the entire circuit. Secondly, by adjusting the ratio of multiple first resistors R1, the current flowing through the Zener diode Dz1 can be controlled more flexibly and precisely to ensure the reliability of the Zener diode Dz1.

[0051] For example, such as Figure 3 As shown, this application takes the current limiting module 111, which includes two first resistors R1 connected in series, as an example. The number of first resistors R1 can be selected according to actual needs, and this application does not impose specific restrictions on this.

[0052] The voltage of the high-voltage DC bus HV is too high. For ease of detection, in one example, such as... Figure 3As shown, the signal input circuit 12 includes a voltage divider module 121 and a first operational amplifier U1. The first terminal of the voltage divider module 121 serves as the first terminal of the signal input circuit 12, connected to the positive terminal HV+ of the high-voltage DC bus HV and one end of the first resistor R1. The second terminal of the voltage divider module 121 serves as the second terminal of the signal input circuit 12, connected to the negative terminal HV- of the high-voltage DC bus HV. The power input terminal of the first operational amplifier U1 serves as the third terminal of the signal input circuit 12, connected to the negative terminal of the Zener diode Dz1 and the other end of the current limiting module 111. The non-inverting input terminal (“+” as shown) of the first operational amplifier U1 is connected to the third terminal of the voltage divider module 121. The inverting input terminal (“-” as shown) of the first operational amplifier U1 serves as the fifth terminal of the signal input circuit 12, connected to the second terminal of the isolation circuit 13 and the fourth terminal of the voltage divider module 121. The output terminal of the first operational amplifier U1 serves as the fourth terminal of the signal input circuit 12 and is connected to the first terminal of the isolation circuit 13.

[0053] The voltage divider module 121 divides the voltage of the high-voltage DC bus HV to obtain a first output voltage Vin. The voltage divider module 121 outputs the first output voltage Vin obtained from the voltage division process to the subsequent circuit (e.g., the first operational amplifier U1). By using the voltage divider module 121, the high voltage of the high-voltage DC bus HV can be reduced to a range suitable for the first operational amplifier U1 to receive, thus avoiding damage to the first operational amplifier U1 caused by directly connecting the high voltage, which would affect the measurement accuracy. In other words, by setting up the voltage divider module 12, measurement accuracy can be improved, ensuring the reliability of signal acquisition by the signal input circuit 12.

[0054] Optional, such as Figure 4 As shown, the voltage divider module 121 includes multiple second resistors R2, third resistors R3, and fourth resistors R4 connected in series. The first end of the second resistor R2, which is not connected to the first resistor R2, serves as the first end of the voltage divider module 121, and is connected to the positive terminal HV+ of the high-voltage DC bus HV and one end of the current limiting module 111 (i.e., one end of the first resistor R1 as shown in the figure). The last end of the second resistor R2, which is not connected to the second resistor R2, serves as the third end of the voltage divider module 121, and is connected to one end of the third resistor R3 and the non-inverting input terminal of the first operational amplifier U1. The other end of the third resistor R3 serves as the second end of the voltage divider module 121, and is connected to the negative terminal HV- of the high-voltage DC bus HV and one end of the fourth resistor R4. The other end of the fourth resistor R4 serves as the fourth end of the voltage divider module 121, and is connected to the inverting input terminal of the first operational amplifier.

[0055] The series connection of multiple second resistors R2 and third resistor R3 acts as a voltage divider, dividing the voltage between the positive terminal HV+ and the negative terminal HV- of the high-voltage DC bus HV, thus obtaining the corresponding first output voltage Vin. For example, as shown... Figure 5 As shown, taking the voltage divider module 121, which includes three second resistors R2 connected in series, as an example, the first output voltage Vin can be obtained according to formula (1):

[0056] Vin=Vhv*R3(R2+R2+R2+R3) (1)

[0057] Wherein, Vin is the first output voltage, Vhv is the voltage between the positive terminal HV+ and the negative terminal HV- of the high voltage DC bus HV, R2 is the resistance value of the second resistor, and R3 is the resistance value of the third resistor.

[0058] This application employs multiple resistors connected in series to divide the voltage of the high-voltage DC bus HV. By appropriately selecting the resistance values ​​of each resistor, the voltage of the high-voltage DC bus HV can be accurately converted into a low voltage (i.e., the first output voltage Vin) suitable for measurement or control. This method offers high voltage division accuracy, low cost, and a low failure rate, improving the reliability of the voltage divider module 121. Furthermore, it facilitates fault location and replacement of damaged components in the event of a failure.

[0059] Optionally, the number of second resistors R2 in the voltage divider module 121 can be selected according to actual needs. The voltage divider module 121 can also be selected from other circuits or devices that can achieve the above-mentioned voltage divider function. This application does not impose specific restrictions on this.

[0060] The voltage divider module 121 typically has a high output impedance, while subsequent circuits (such as the isolation circuit 13) may require a lower input impedance. In this case, the first operational amplifier U1 can act as a buffer circuit, converting the high-impedance signal (i.e., the first output voltage Vin) into a low-impedance signal, thereby achieving good impedance matching. Furthermore, the first operational amplifier U1 can also amplify the first output voltage Vin before outputting it to the isolation circuit 13, thereby improving the reliability of the signal connected to the isolation circuit 13.

[0061] In one example, such as Figure 3 As shown, the isolation circuit 13 is a linear optocoupler U4, which includes a light-emitting diode (LED), a first photodiode (PD) PD1, and a second photodiode PD2.

[0062] In this circuit, the positive terminal of the light-emitting diode (LED) serves as the first terminal of the isolation circuit 13 and the fourth terminal of the signal input circuit 12 (i.e., as shown in the image). Figure 4 The output terminal of the first operational amplifier U1 is connected, and the negative terminal of the light-emitting diode (LED) is grounded. The positive terminal of the first photodiode PD1 is connected to the fifth terminal of the signal input circuit 12 as the second terminal of the isolation circuit 13, and the negative terminal of the first photodiode PD1 is connected to the third terminal of the power supply circuit 11 as the third terminal of the isolation circuit 13, so as to connect to the first low-voltage power supply VCC1. The second photodiode PD2 is connected to the signal processing circuit 14.

[0063] In this example, assume the current in the LED is If, the current generated in the first photodiode PD1 is I1, the current generated in the second photodiode PD2 is I2, and the typical value of the transmission gain k of the linear optocoupler U3 is 1. When the first operational amplifier U1 receives the first output voltage Vin, it amplifies it and outputs it to the positive terminal of the LED. At this time, a current If flows through the LED, and the magnitude of this current If changes accordingly with the input voltage. When the LED emits current If, it emits light to convert the electrical signal into a light signal. At this time, the first photodiode PD1 detects the light emitted by the LED.

[0064] Assuming the first operational amplifier U1 is an ideal operational amplifier, an ideal operational amplifier exhibits two phenomena: virtual open circuit and virtual short circuit. Under the virtual open circuit phenomenon, the input impedance of the ideal operational amplifier is infinite, therefore the current flowing into the two input terminals of the first operational amplifier U1 is zero, that is, the input current of the first operational amplifier U1 is zero. Under the virtual short circuit phenomenon, when the ideal operational amplifier operates in the linear region, the voltages at the two input terminals of the first operational amplifier U1 are equal, that is, the input voltages of the first operational amplifier U1 are equal. Correspondingly, the current I1 generated on the first photodiode PD1 will be entirely output to the negative terminal HV- of the high-voltage DC bus HV through the fourth resistor R4. At this time, the first output voltage Vin can be obtained according to formula (2):

[0065] Vin=I1*R4 (2)

[0066] Where I1 is the current generated on the first photodiode, and R4 is the resistance value of the fourth resistor.

[0067] At this point, due to the introduction of negative feedback, the current I1 generated on the first photodiode PD1 depends only on the first output voltage Vin and the resistance value of the fourth resistor R4, and is unrelated to the light output characteristics of the LED.

[0068] Correspondingly, the current I2 generated on the second photodiode PD2 can be obtained according to formula (3):

[0069] I2=K*I1 (3)

[0070] Where K is the transmission gain of the linear optical coupler, and K = 1.

[0071] The current generated on the second photodiode PD2 is output to the signal processing circuit 14, so that the signal processing circuit 14 determines the voltage of the high voltage DC bus HV based on the current.

[0072] Thus, the linear optocoupler U4 transmits information via optical signals, achieving complete electrical isolation between the high-voltage side circuit (i.e., signal input circuit 12) and the low-voltage side circuit (i.e., signal processing circuit 14), thereby improving the safety of the low-voltage side circuit. Secondly, the linear optocoupler U4 has a fast response time and maintains high linearity between its input and output. This allows the linear optocoupler U4 to provide precise current to the signal processing circuit 14 based on the output of the first operational amplifier U1, ensuring the accuracy and reliability of the signal processing circuit 14's detection of the high-voltage DC bus HV based on this output. Furthermore, compared to dedicated isolation amplifier chips, the linear optocoupler U4 has a lower cost.

[0073] To improve the reliability of the signal output from the first operational amplifier U1 to the isolation circuit 13, in one example, such as Figure 5 As shown, the isolation detection system 1 also includes a second capacitor C2 and a seventh resistor R7. The first plate of the second capacitor C2 is connected to the output terminal of the first operational amplifier U1, the second plate of the second capacitor C2 is connected to the other end of the fourth resistor R4, one end of the seventh resistor R7 is connected to the first plate of the second capacitor C2, and the other end of the seventh resistor R7 is connected to the first terminal of the isolation circuit 13 (i.e., the positive terminal of the light-emitting diode LED as shown in the figure).

[0074] In this example, the second capacitor C2 and the seventh resistor R7 can filter the signal output by the first operational amplifier U1 to filter out high-frequency spike pulses in the circuit, prevent the circuit from oscillating, and further improve the integrity and accuracy of the signal output to the isolation circuit 13, so as to further ensure the detection reliability of the isolation detection system 1.

[0075] In order for the signal processing circuit 14 to determine the voltage of the high-voltage DC bus HV based on the current output of the isolation circuit 13, in one example, such as Figure 5As shown, the signal processing circuit 14 includes a voltage conversion module 141 and a controller 142. The first terminal of the voltage conversion module 141 is connected to the positive terminal of the second photodiode PD2, the second terminal of the voltage conversion module 141 is connected to the negative terminal of the second photodiode PD2, and the controller 142 is connected to the third terminal of the voltage conversion module 141.

[0076] In this example, the voltage conversion module 141 converts the current output by the second photodiode PD2 into voltage, enabling it to output a second output voltage Vout to the controller 142. The controller 142 then performs a digital-to-analog conversion on the second output voltage Vout to determine the voltage of the high-voltage DC bus HV. Thus, by converting current into a second output voltage Vout through the voltage conversion module 141, and then performing a digital-to-analog conversion on Vout through the controller 142 to determine the corresponding voltage of the high-voltage DC bus HV, accurate detection of the high-voltage DC bus HV is achieved. This allows for timely detection of voltage anomalies, enabling subsequent operators to take appropriate remedial measures based on the anomaly, ensuring stable vehicle operation.

[0077] In order for the voltage conversion module 141 to convert the current into a second output voltage Vout, in one example, such as Figure 6 As shown, the voltage conversion module 141 includes a second operational amplifier U2 and a fifth resistor R5. The non-inverting input of the second operational amplifier U2 serves as the first terminal of the voltage conversion module 141 and is connected to the positive terminal of the second photodiode PD2. The power input of the second operational amplifier U2 serves as the second terminal of the voltage conversion module 141 and is connected to the negative terminal of the second photodiode PD2, and is also connected to a second low-voltage power supply VCC2, which can be a low-voltage power supply directly provided by a low-voltage battery. The output of the second operational amplifier U2 serves as the third terminal of the voltage conversion module 141 and is connected to the controller 142 and the inverting input of the second operational amplifier U2. One end of the fifth resistor R5 is connected to the non-inverting input of the second operational amplifier U2, and the other end of the fifth resistor R5 is grounded.

[0078] In this example, the second operational amplifier U2 and the fifth resistor R5 will convert the current into the second output voltage Vout, which can be obtained according to formula (4):

[0079] Vout=I2*R5 (4)

[0080] R5 is the resistance value of the fifth resistor.

[0081] Formula (5) can be derived from the above formulas (1) to (4):

[0082] Vout / Vhv=k*R3R5 / R4(R2+R2+R2+R3) (5)

[0083] Since the typical value of the transmission gain of the linear optocoupler U4 is 1, the corresponding Vout / Vhv = R3R5 / R4(R2+R2+R2+R3).

[0084] Assuming that the resistance values ​​of the fifth resistor R5 and the fourth resistor R4 are equal, we can obtain formula (6):

[0085] Vout / Vhv=R3 / (R2+R2+R2+R3) (6)

[0086] According to formula (6), there is a linear relationship between the second output voltage Vout and the voltage Vhv of the high-voltage DC bus HV under test, and their ratio can be achieved by adjusting the resistance values ​​of each voltage divider resistor (the second resistor R2 and the third resistor R3). Correspondingly, the controller 15 can calculate the voltage Vhv of the high-voltage DC bus HV under test based on the second output voltage Vout output by the second operational amplifier U2, so as to achieve accurate detection of the high-voltage DC bus HV.

[0087] In this example, the second operational amplifier U2 acts as a non-inverting amplifier. Compared to an inverting amplifier, a non-inverting amplifier is suitable for high-impedance signal sources (such as photodiodes) and has better noise performance. Furthermore, the second operational amplifier U2 can maintain the same phase between its input and output signals, ensuring the reliability of its second output voltage Vout based on the current output.

[0088] In another example, such as Figure 7 As shown, the voltage conversion module 141 includes a third operational amplifier U3, a sixth resistor R6, and a first capacitor C1. The non-inverting input terminal of the third operational amplifier U3 serves as the first terminal of the voltage conversion module 141 and is connected to the positive terminal of the second photodiode PD2. The inverting input terminal of the third operational amplifier U3 serves as the second terminal of the voltage conversion module 141 and is connected to the negative terminal of the second photodiode PD2. The output terminal of the third operational amplifier U3 serves as the third terminal of the voltage conversion module 141 and is connected to the controller 142. One end of the sixth resistor R6 is connected to the inverting input terminal of the third operational amplifier U3, and the other end of the sixth resistor R6 is connected to the output terminal of the third operational amplifier U3 and the controller 142. The first plate of the first capacitor C1 is connected to one end of the sixth resistor R6 and the inverting input terminal of the third operational amplifier U3, and the second plate of the first capacitor C1 is connected to the other end of the sixth resistor R6, the output terminal of the third operational amplifier U3, and the controller 142.

[0089] In this example, the third operational amplifier U3 acts as an inverting amplifier. Compared to a non-inverting amplifier, the inverting amplifier provides more stable signal processing and can amplify the signal in reverse phase, ensuring the reliability of its second output voltage Vout based on the current output. The third operational amplifier U3 and the sixth resistor R6 can convert the current into the second output voltage Vout. The conversion process and formula are the same as those for the second operational amplifier U2 described above, and will not be repeated here.

[0090] To further improve the integrity of the signal output to controller 142, in one example, such as Figure 7 As shown, the isolation detection system 1 also includes an eighth resistor R8 and a third capacitor C3. One end of the eighth resistor R8 is connected to the output terminal of the third operational amplifier U3, the first plate of the third capacitor C3 is connected to the other end of the eighth resistor R8 and the controller 142, and the second plate of the third capacitor C3 is grounded.

[0091] In this example, the third capacitor C3 and the eighth resistor R8 can filter the signal output by the third operational amplifier U3 to attenuate the high-frequency noise in the second output voltage Vout, improve the integrity and accuracy of the second output voltage Vout output to the controller 142, and further ensure the detection reliability of the isolation detection system 1.

[0092] In one example, such as Figure 7 As shown, the isolation detection system 1 also includes a Zener diode Dz2. The positive terminal of the Zener diode Dz2 is connected to the second plate of the third capacitor C3 and grounded. The Zener diode Dz2 is connected to the first plate of the third capacitor C3, the other end of the eighth resistor R8, and the controller 142.

[0093] In this example, the Zener diode Dz2 operates in the reverse breakdown region. When the voltage across its terminals exceeds the set Zener voltage, it's worth noting that the Zener diode Dz2 is connected to ground and the second output voltage Vout, respectively. The ground voltage is a stable voltage. That is, when the second output voltage Vout is overvoltage, the Zener diode Dz2 will conduct and clamp the voltage at the Zener voltage, thus limiting the voltage. The Zener diode Dz2 ensures that the second output voltage Vout received by the controller 142 is always within a safe operating range, preventing damage to the controller 142 from overvoltage and ensuring the reliability of the controller 142's use and detection. Furthermore, the Zener diode Dz2 has a fast response speed to voltage changes, quickly clamping transient voltage spikes or short-term overvoltage situations to effectively protect the controller 142.

[0094] Optionally, the controller 142 may be a microcontroller unit (MCU).

[0095] In summary, the power supply circuit 11 in this application can directly convert the high-voltage electricity from the high-voltage DC bus HV into a first low-voltage power supply VCC1 and output it to the signal input circuit 12 on the high-voltage side, enabling the signal input circuit 12 to operate normally based on this first low-voltage power supply VCC1. That is, the high-voltage side circuit (i.e., the signal input circuit 12) in this application can be directly powered by the high-voltage DC bus HV without the need for additional conversion devices, resulting in lower power supply costs. Furthermore, the high-voltage side power supply and the low-voltage side power supply are mutually isolated, preventing the high-voltage side circuit from potentially transmitting high voltage to the low-voltage side circuit through the power lines, which could damage the low-voltage side circuit and pose a significant safety hazard. This results in higher power supply stability, thereby improving the reliability of each component in the system and ensuring the reliability of the isolation detection system 1. This allows the isolation detection system 1 provided in this application to reliably detect the voltage of the high-voltage DC bus HV, promptly identify voltage anomalies, and enable subsequent operators to take appropriate remedial measures based on the anomaly to ensure stable vehicle operation. Secondly, by setting up the isolation circuit 13, electrical isolation between the high-voltage side circuit and the low-voltage side circuit can be achieved, so as to avoid the voltage of the high-voltage DC bus HV being directly applied to the low-voltage side circuit, which would cause damage to the low-voltage side circuit. While ensuring that the low-voltage side circuit can be used normally, the overall safety of the system is improved, so as to further ensure the detection reliability of the system.

[0096] 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.

[0097] 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.

[0098] 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. An isolation detection system, characterized in that, The isolation detection system includes: The power supply circuit has a first terminal connected to the positive terminal of the high-voltage DC bus, a second terminal grounded, and a third terminal used to output a first low-voltage power supply. A signal input circuit, wherein the first terminal of the signal input circuit is connected to the positive terminal of the high-voltage DC bus and the first terminal of the power supply circuit, the second terminal of the signal input circuit is connected to the negative terminal of the high-voltage DC bus, and the third terminal of the signal input circuit is connected to the third terminal of the power supply circuit, so as to connect to the first low-voltage power supply. An isolation circuit, wherein a first terminal of the isolation circuit is connected to a fourth terminal of the signal input circuit, a second terminal of the isolation circuit is connected to a fifth terminal of the signal input circuit, and a third terminal of the isolation circuit is connected to a third terminal of the power supply circuit, for connection to the first low-voltage power supply; and, A signal processing circuit is connected to the isolation circuit, and the signal processing circuit is used to determine the voltage of the high voltage DC bus based on the output current of the isolation circuit.

2. The isolation detection system according to claim 1, characterized in that, The power supply circuit includes: A current limiting module, one end of which is connected as the first terminal of the power supply circuit to the positive terminal of the high-voltage DC bus; and... A Zener diode, the negative terminal of which serves as the third terminal of the power supply circuit and is connected to the third terminal of the signal input circuit and the other terminal of the current limiting module, and the positive terminal of which serves as the second terminal of the power supply circuit and is grounded.

3. The isolation detection system according to claim 2, characterized in that, The current limiting module includes multiple first resistors connected in series; The end of the first resistor located at the beginning that is not connected to the first resistor serves as one end of the current limiting module and is connected to the positive terminal of the high-voltage DC bus. The end of the first resistor located at the end that is not connected to the first resistor serves as the other end of the current limiting module and is connected to the negative terminal of the Zener diode and the third terminal of the signal input circuit.

4. The isolation detection system according to claim 2, characterized in that, The signal input circuit includes: A voltage divider module, wherein the first terminal of the voltage divider module serves as the first terminal of the signal input circuit, connected to the positive terminal of the high-voltage DC bus and one end of the current limiting module; and the second terminal of the voltage divider module serves as the second terminal of the signal input circuit, connected to the negative terminal of the high-voltage DC bus; and... The first operational amplifier has its power input terminal serving as the third terminal of the signal input circuit, connected to the negative terminal of the Zener diode and the other end of the current limiting module. The non-inverting input terminal of the first operational amplifier is connected to the third terminal of the voltage divider module. The inverting input terminal of the first operational amplifier serves as the fifth terminal of the signal input circuit, connected to the second terminal of the isolation circuit and the fourth terminal of the voltage divider module. The output terminal of the first operational amplifier serves as the fourth terminal of the signal input circuit and is connected to the first terminal of the isolation circuit.

5. The isolation detection system according to claim 4, characterized in that, The voltage divider module includes multiple second resistors, third resistors, and fourth resistors connected in series; The end of the second resistor located at the first position that is not connected to the second resistor serves as the first terminal of the voltage divider module, and is connected to the positive terminal of the high-voltage DC bus and one end of the current limiting module. The end of the second resistor located at the last position that is not connected to the second resistor serves as the third terminal of the voltage divider module, and is connected to one end of the third resistor and the non-inverting input terminal of the first operational amplifier. The other end of the third resistor serves as the second terminal of the voltage divider module, and is connected to the negative terminal of the high-voltage DC bus and one end of the fourth resistor. The other end of the fourth resistor serves as the fourth terminal of the voltage divider module and is connected to the inverting input terminal of the first operational amplifier.

6. The isolation detection system according to any one of claims 1-5, characterized in that, The isolation circuit is a linear optocoupler, which includes: A light-emitting diode (LED) is provided, with its positive terminal connected to the fourth terminal of the signal input circuit as the first terminal of the isolation circuit, and its negative terminal grounded. A first photodiode, the anode of which is connected as the second terminal of the isolation circuit to the fifth terminal of the signal input circuit, and the cathode of which is connected as the third terminal of the isolation circuit to the third terminal of the power supply circuit; and, The second photodiode is connected to the signal processing circuit.

7. The isolation detection system according to claim 6, characterized in that, The signal processing circuit includes: A voltage conversion module, wherein a first terminal of the voltage conversion module is connected to the positive terminal of the second photodiode, and a second terminal of the voltage conversion module is connected to the negative terminal of the second photodiode; and, A controller is connected to the third terminal of the voltage conversion module.

8. The isolation detection system according to claim 7, characterized in that, The voltage conversion module includes: A second operational amplifier, wherein the non-inverting input of the second operational amplifier is connected as the first terminal of the voltage conversion module and to the positive terminal of the second photodiode; the power input of the second operational amplifier is connected as the second terminal of the voltage conversion module and to the negative terminal of the second photodiode; and the output of the second operational amplifier is connected as the third terminal of the voltage conversion module and to the controller and the inverting input of the second operational amplifier; and, The fifth resistor has one end connected to the non-inverting input of the second operational amplifier, and the other end grounded.

9. The isolation detection system according to claim 7, characterized in that, The voltage conversion module includes: The third operational amplifier has its non-inverting input terminal connected to the positive terminal of the second photodiode as the first terminal of the voltage conversion module, its inverting input terminal connected to the negative terminal of the second photodiode as the second terminal of the voltage conversion module, and its output terminal connected to the controller as the third terminal of the voltage conversion module. A sixth resistor, one end of which is connected to the inverting input of the third operational amplifier, and the other end of which is connected to the output of the third operational amplifier and the controller; and, The first capacitor has its first plate connected to one end of the sixth resistor and the inverting input of the third operational amplifier, and its second plate connected to the other end of the sixth resistor, the output of the third operational amplifier, and the controller.

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

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