Insulation detection circuit and method, battery management system and vehicle

Abstract

An insulation detection circuit and method, a battery management system and a vehicle. The circuit (100) comprises: a power supply unit (10) suitable for providing a first power supply and a second power supply, wherein the supply voltages of the first power supply and the second power supply are different; a switching unit (20) suitable for making the power supply unit (10) switch between connection to a positive terminal of a load and connection to a negative terminal of the load; and a voltage measurement unit (30) configured to measure a voltage between the first power supply and a ground terminal and measure a voltage between the second power supply and the ground terminal, wherein the voltages measured by the voltage measurement unit (30) are configured to determine insulation resistance. Therefore, whether the power supply unit (10) is connected to the positive terminal of the load or the negative terminal of the load, the insulation resistance of the ground terminal can be measured.

Description

Insulation detection circuit and method, battery management system, vehicle

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure claims priority to Chinese patent application number 202311001079.5, filed on August 9, 2023, entitled “INSULATION DETECTION CIRCUIT AND METHOD, BATTERY MANAGEMENT SYSTEM, VEHICLE,” the entire contents of which are incorporated by reference into this disclosure. Technical Field

[0003] The present disclosure relates to the field of insulation detection, and in particular to an insulation detection circuit and method, a battery management system, and a vehicle. Background Art

[0004] New energy vehicle technology has become a cutting-edge science in current automotive development. Electric vehicles are steadily gaining market share from traditional fuel-powered vehicles. The Battery Management System (BMS) is one of the core "three-electric" technologies in new energy vehicles. The BMS handles functions such as high-voltage interlocking, SOC (State of Charge), SOH (State of Health), relay drive, and cell voltage and temperature acquisition. Insulation testing is a key indicator of the insulation performance between high and low voltages.

[0005] Summary of the Invention

[0006] An insulation detection circuit and method, a battery management system, and a vehicle are provided, which can detect the insulation resistance of a ground terminal regardless of whether a power supply unit is connected to the positive terminal or the negative terminal of a load.

[0007] In a first aspect, the present disclosure proposes an insulation detection circuit, which includes: a power supply unit, suitable for providing a first power supply and a second power supply, wherein the supply voltages of the first power supply and the second power supply are different; a switching unit, suitable for switching the power supply unit to be connected to the positive terminal of the load or the negative terminal of the load; a voltage detection unit, configured to detect the voltage between the first power supply and the ground terminal, and to detect the voltage between the second power supply and the ground terminal; wherein the voltage detected by the voltage detection unit is used to determine the insulation resistance.

[0008] According to the insulation detection circuit of the embodiment of the present disclosure, the insulation resistance of the ground terminal can be detected regardless of whether the power supply unit is connected to the positive terminal or the negative terminal of the load.

[0009] In a second aspect, the present disclosure provides a battery management system, including the insulation detection circuit.

[0010] According to the battery management system of the embodiment of the present disclosure, the insulation resistance of the ground terminal can be detected through the insulation detection circuit regardless of whether the power supply unit is connected to the positive terminal or the negative terminal of the load.

[0011] In a third aspect, the present disclosure provides a vehicle, comprising the battery management system.

[0012] According to the vehicle of the embodiment of the present disclosure, through the battery management system, the insulation resistance of the ground terminal can be detected regardless of whether the power supply unit is connected to the positive terminal or the negative terminal of the load.

[0013] In a fourth aspect, the present disclosure proposes an insulation detection method, which is applied to a battery management system. The battery management system includes a power supply unit and a switching unit. The power supply unit is suitable for providing a first power supply and a second power supply, wherein the supply voltages of the first power supply and the second power supply are different. The switching unit is suitable for switching the power supply unit to the positive terminal of the load or the negative terminal of the load. The method includes: detecting the voltage between the first power supply and the ground terminal, and detecting the voltage between the second power supply and the ground terminal; determining the insulation resistance based on the detected voltage.

[0014] According to the insulation detection method of the embodiment of the present disclosure, the insulation resistance of the ground terminal can be detected regardless of whether the power supply unit is connected to the positive terminal or the negative terminal of the load.

[0015] Additional aspects and advantages of the present disclosure will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG1 is a schematic structural diagram of an insulation detection circuit according to an embodiment of the present disclosure;

[0017] FIG2 is a schematic structural diagram of an insulation detection circuit according to a first embodiment of the present disclosure;

[0018] FIG3 is a schematic structural diagram of an insulation detection circuit according to a second specific embodiment of the present disclosure;

[0019] FIG4 is a schematic structural diagram of an insulation detection circuit according to a third specific embodiment of the present disclosure;

[0020] FIG5 is a schematic diagram of a battery management system according to an embodiment of the present disclosure;

[0021] FIG6 is a schematic diagram of a vehicle according to an embodiment of the present disclosure;

[0022] FIG7 is a flow chart of an insulation detection method according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0023] The following describes in detail embodiments of the present disclosure, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present disclosure, and should not be construed as limiting the present disclosure.

[0024] FIG1 is a schematic diagram of the structure of an insulation detection circuit according to an embodiment of the present disclosure. As shown in FIG1 , the insulation detection circuit 100 includes: a power supply unit 10 , a switching unit 20 and a voltage detection unit 30 .

[0025] In this example, the power supply unit 10 is adapted to provide a first power source and a second power source, wherein the supply voltages of the first power source and the second power source are different.

[0026] Specifically, due to the introduction of the supply voltage of the first power supply and the supply voltage of the second power supply, the calculation of the insulation resistance at the load end does not depend on the battery voltage and the generated voltage of the load L. That is, even when the load L is in discharge mode, it does not affect the insulation resistance measurement at the load end, thereby increasing the scope of application of the insulation detection circuit 100. The supply voltage of the first power supply and the supply voltage of the second power supply can be provided by a transformer, a DC / DC (Direct Current / Direct Current) converter, or a small battery. Since the national standard requires not to exceed 60V, the load end is limited and the residual voltage does not exceed the standard value, the supply voltage of the first power supply is 48V (volts) and the supply voltage of the second power supply is 24V (volts) in this example. It should be noted that when the supply voltage of the first power supply can be 24V and the supply voltage of the second power supply can be 12V (volts), the macro principle is feasible, but the actual effect of micro experiments is very poor and the inspection error is too large.

[0027] In this example, the switching unit 20 is adapted to switch the power supply unit 10 between the positive terminal of the load L and the negative terminal of the load L. The voltage detection unit 30 detects the voltage between the first power supply and the ground terminal GND, and detects the voltage between the second power supply and the ground terminal GND; the voltage detected by the voltage detection unit 30 is used to determine the insulation resistance.

[0028] Specifically, the power supply unit 10 can provide a first power supply for 450ms, that is, after the circuit is stable, the voltage between the first power supply and the ground terminal GND is detected, and the power supply unit 10 can provide a second power supply for 450ms, that is, after the circuit is stable, the voltage between the second power supply and the ground terminal GND is detected.

[0029] Therefore, no matter whether the power supply unit is connected to the positive terminal or the negative terminal of the load, the insulation resistance of the ground terminal can be detected.

[0030] As an example, the voltage detection unit 30 is configured to, when the power supply unit 10 is connected to the positive terminal,

[0031] If the power supply unit 10 provides a first power supply, the voltage between the first power supply and the ground terminal GND is detected to obtain a first detection voltage (U2); if the power supply unit 10 provides a second power supply, the voltage between the second power supply and the ground terminal GND is detected to obtain a second detection voltage (U4);

[0032] The voltage detection unit 30 is further configured to, when the power supply unit 10 is connected to the negative terminal,

[0033] If the power supply unit 10 provides the first power supply, the voltage between the first power supply and the ground terminal GND is detected to obtain a third detection voltage (U2'); if the power supply unit 10 provides the second power supply, the voltage between the second power supply and the ground terminal GND is detected to obtain a fourth detection voltage (U4');

[0034] The first detection voltage (U2) to the fourth detection voltage (U4') are used to determine the insulation resistance Rp between the positive terminal and the ground terminal GND and the insulation resistance Rn between the negative terminal and the ground terminal GND (see FIG3).

[0035] It should be noted that, referring to Figure 3, the insulation detection circuit 100 may also include an insulation capacitor Yp between the positive terminal and the ground terminal GND and an insulation capacitor Yn between the negative terminal and the ground terminal GND, wherein the insulation capacitor Yp between the positive terminal and the ground terminal GND may be 1uF (microfarad), and the insulation capacitor Yn between the negative terminal and the ground terminal GND may be 1uF (microfarad).

[0036] As an example, referring to FIG2 , the insulation detection circuit 100 may further include a first resistor RF1 and a second resistor RF2; one end of the first resistor RF1 is connected to the positive terminal, one end of the second resistor RF2 is respectively connected to the other end of the first resistor RF1 and the voltage detection unit 30 and has a first node N, and the other end of the second resistor RF2 is respectively connected to the ground terminal GND and the voltage detection unit 30. The voltage detection unit 30 is further configured to,

[0037] When the power supply unit 10 is connected to the positive terminal and provides the first power supply, the voltage of the first node N is detected to obtain a fifth detection voltage (U1);

[0038] When the power supply unit 10 is connected to the positive terminal and provides the second power supply, the voltage of the first node N is detected to obtain a sixth detection voltage (U3);

[0039] The fifth detection voltage (U1) and the first detection voltage (U2) are used to determine the actual voltage (V1) of the first power supply, the sixth detection voltage (U3) and the second detection voltage (U4) are used to determine the actual voltage (V2) of the second power supply, the actual voltage of the first power supply, the actual voltage of the second power supply, the first detection voltage (U2) and the second detection voltage (U4) are used to determine the insulation resistance of the positive terminal to the ground terminal GND, and the actual voltage of the first power supply, the actual voltage of the second power supply, the third detection voltage (U2') and the fourth detection voltage (U4') are used to determine the insulation resistance of the negative terminal to the ground terminal GND.

[0040] Specifically, in an actual circuit, the injected voltage will change in real time according to factors such as temperature, noise, and radiation. The role of the first resistor RF1 and the second resistor RF2 connected in parallel in the bridge can monitor the injected voltage in real time, ensuring that the actual voltage at the moment of injection is accurately measured, so that the value substituted into the formula is closer to the actual value and the result is more accurate.

[0041] The actual voltage V1 of the first power supply satisfies: The actual voltage V2 of the second power supply satisfies: Wherein, U1 is the fifth detection voltage, U2 is the first detection voltage, U3 is the sixth detection voltage, U4 is the second detection voltage, R4 is the resistance value of the first resistor RF1, and R5 is the resistance value of the second resistor RF2.

[0042] It should be noted that, since the differential operation is adopted when the power supply unit 10 is connected to the positive terminal and the power supply unit 10 provides the first power supply, the voltage of the first node N detected (i.e., the fifth detection voltage U1) and the voltage between the first power supply and the ground terminal GND (i.e., the first detection voltage U2), and the differential operation is adopted when the power supply unit 10 is connected to the positive terminal and the power supply unit 10 provides the second power supply, the voltage of the first node N detected (i.e., the sixth detection voltage U3) and the voltage between the second power supply and the ground terminal GND (i.e., the second detection voltage U4), it is possible to effectively reduce errors caused by external interference, improve the robustness of the system, and enhance the anti-interference ability.

[0043] As a first example, the voltage detection unit 30 is further configured to:

[0044] If the power supply unit 10 is connected to the positive terminal and provides the first power supply, the voltage between the positive terminal and the negative terminal is detected to obtain a seventh detection voltage (V3);

[0045] If the power supply unit 10 is connected to the negative terminal and provides the first power supply, the voltage between the positive terminal and the negative terminal is detected to obtain an eighth detection voltage (V5);

[0046] Among them, the first detection voltage (U2), the third detection voltage (U2'), the actual voltage (V1) of the first power supply, the seventh detection voltage (V3) and the eighth detection voltage (V5) are used to determine the insulation resistance of the positive terminal to the ground terminal GND and the insulation resistance of the negative terminal to the ground terminal GND when the load L connected between the positive terminal and the negative terminal is in the power generation mode.

[0047] As a second example, the voltage detection unit 30 is further configured to:

[0048] If the power supply unit 10 is connected to the positive terminal and provides the second power supply, the voltage between the positive terminal and the negative terminal is detected to obtain a ninth detection voltage (V4);

[0049] If the power supply unit 10 is connected to the negative terminal and the power supply unit 10 provides the second power supply, the voltage between the positive terminal and the negative terminal is detected to obtain a tenth detection voltage (V6);

[0050] The second detection voltage (U4), the fourth detection voltage (U4'), the actual voltage (V2) of the second power supply, the ninth detection voltage (V4) and the tenth detection voltage (V6) are used to determine the insulation resistance between the positive terminal and the ground terminal GND and the insulation resistance between the negative terminal and the ground terminal GND when the load L is in the power generation mode.

[0051] 4 , the insulation detection circuit 100 may further include a controller 40 configured to determine whether the load L connected between the positive terminal and the negative terminal is in the power generation mode when the seventh detection voltage (V3) and the ninth detection voltage (V4) are each greater than a first preset voltage (e.g., 50V), or when the eighth detection voltage (V5) and the tenth detection voltage (V6) are each greater than a second preset voltage (e.g., 50V). Thus, whether the load L connected between the positive terminal and the negative terminal is in the power generation mode is determined based on the seventh detection voltage (V3) and the ninth detection voltage (V4) or the eighth detection voltage (V5) and the tenth detection voltage (V6).

[0052] It should be noted that, first, if the seventh detection voltage (V3) and the ninth detection voltage (V4) are both 0V, and the eighth detection voltage (V5) and the tenth detection voltage (V6) are both 0V, it can be proved that the load L has not entered the power generation mode at this time, and the Rp and Rn values ​​(i.e., the insulation resistance Rp3 of the positive terminal to the ground terminal GND and the insulation resistance Rn3 of the negative terminal to the ground terminal GND) can be calculated by the following formula.

[0053] Second, it is also possible to directly determine whether load L is in power generation mode through load L. In addition, whether load L is in power generation mode is determined by the operating conditions of load L. The hybrid mode may or may not be in power generation mode, and the situation is uncertain.

[0054] Third, when the seventh detection voltage (V3) does not exist, Kirchhoff's current law is mainly used to establish a mathematical model and solve the equation; when V3 exists, the superposition theorem is mainly used to establish a mathematical model and solve the equation.

[0055] As an example, the controller 40 is further configured to:

[0056] If the first voltage change rate determined based on the seventh detection voltage (V3) and the ninth detection voltage (V4) is less than a first preset change rate (e.g., 0.5 V / s), determining the insulation resistance of the positive terminal to the ground terminal GND and the insulation resistance of the negative terminal to the ground terminal GND based on the first detection voltage (U2), the third detection voltage (U2'), the actual voltage (V1) of the first power supply, the seventh detection voltage (V3), and the eighth detection voltage (V5);

[0057] If a second voltage change rate (e.g., 0.5 V / s) determined based on the eighth detection voltage (V5) and the tenth detection voltage (V6) is less than a second preset change rate, the insulation resistance of the positive terminal to the ground terminal GND and the insulation resistance of the negative terminal to the ground terminal GND are determined based on the second detection voltage (U4), the fourth detection voltage (U4'), the actual voltage (V2) of the second power supply, the ninth detection voltage (V4), and the tenth detection voltage (V6).

[0058] Specifically, the first voltage change rate Second voltage change rate Wherein, V3 is the seventh detection voltage (V3), V4 is the ninth detection voltage (V4), V5 is the eighth detection voltage (V5), V6 is the tenth detection voltage (V6), T1 is the time when the power supply unit 10 is connected to the negative terminal, and T2 is the time when the power supply unit 10 is connected to the positive terminal. Thus, the voltage change rate of the load terminal voltage connected between the positive terminal and the negative terminal can be determined using the seventh detection voltage (V3) and the ninth detection voltage (V4), or the eighth detection voltage (V5) and the tenth detection voltage (V6).

[0059] It should be noted that if the first voltage change rate determined based on the seventh detection voltage (V3) and the ninth detection voltage (V4) is greater than or equal to the first preset change rate, it is necessary to re-collect the seventh detection voltage (V3) and the ninth detection voltage (V4); if the second voltage change rate determined based on the eighth detection voltage (V5) and the tenth detection voltage (V6) is greater than or equal to the second preset change rate, it is necessary to re-collect the eighth detection voltage (V5) and the tenth detection voltage (V6).

[0060] Therefore, the working mode of the load is identified by the voltage between the positive terminal and the negative terminal (i.e., the load terminal voltage) and the voltage change rate, so that the circuit topology under different working modes can be flexibly switched and different sets of equations can be brought in for solution to better calculate the insulation resistance.

[0061] 3-4 , the switching unit 20 may include: a switching switch S1, wherein a first end of the switching switch S1 is connected to a first end of the power supply unit 10, a second end of the switching switch S1 is connected to a positive terminal through a third resistor RF3, and a third end of the switching switch S1 is connected to a negative terminal through a fourth resistor RF4.

[0062] Specifically, when the first end and the second end of the switch S1 are connected, the power supply unit 10 is connected to the positive terminal; when the first end and the third end of the switch S1 are connected, the power supply unit 10 is connected to the negative terminal.

[0063] 2-3 , the power supply unit 10 may include: a first power supply P1 , a second power supply P2 , a first power switch PS1 , and a second power switch PS2 ;

[0064] A first end of the first power switch PS1 is connected to a first end of the switch S1, a second end of the first power switch PS1 is connected to a negative electrode of the first power source P1, and a third end of the first power switch PS1 is connected to a negative electrode of the second power source P2;

[0065] The first terminal of the second power switch PS2 is connected to the ground terminal GND via a fifth resistor RF5. The second terminal of the second power switch PS2 is connected to the positive terminal of the first power supply P1. The third terminal of the second power switch PS2 is connected to the positive terminal of the second power supply P2. It should be noted that while it is theoretically possible to have different polarities for the first and second power supplies P1 and P2, this can lead to significant errors. The present disclosure, by setting the first and second power supplies P1 and P2 to the same polarity, mitigates (reduces) this error by utilizing the voltage difference.

[0066] Specifically, when the first end of the first power switch PS1 is connected to the second end and the first end of the second power switch PS2 is connected to the second end, the power supply unit 10 provides the first power supply P1; when the first end of the first power switch PS1 is connected to the third end and the first end of the second power switch PS2 is connected to the third end, the power supply unit 10 provides the second power supply P2.

[0067] Specifically, when the load L connected between the positive terminal and the negative terminal is in the power generation mode and the power supply unit 10 provides the first power P1, the first insulation resistance may include: an insulation resistance Rp1 between the positive terminal and the ground terminal GND and an insulation resistance Rn1 between the negative terminal and the ground terminal GND;

[0068] Among them, U2 is the first detection voltage, U2' is the third detection voltage, R3 is the resistance of the third resistor RF3, R5 is the resistance of the fifth resistor RF5, V3 is the seventh detection voltage, V5 is the eighth detection voltage, and V1 is the actual voltage of the first power supply P1.

[0069] When the load L is in the power generation mode and the power supply unit 10 provides the second power P2, the second insulation resistance may include: an insulation resistance Rp2 between the positive terminal and the ground terminal GND and an insulation resistance Rn2 between the negative terminal and the ground terminal GND;

[0070] Among them, U4 is the second detection voltage, U4' is the fourth detection voltage, R3 is the resistance of the third resistor RF3, R4 is the resistance of the fourth resistor RF4, R5 is the resistance of the fifth resistor RF5, V4 is the ninth detection voltage, V6 is the tenth detection voltage, and V2 is the actual voltage of the second power supply P2.

[0071] When the load L is not in the power generation mode, the insulation resistance includes: the insulation resistance Rp3 between the positive terminal and the ground terminal GND and the insulation resistance Rn3 between the negative terminal and the ground terminal GND;

[0072] Among them, V1 is the actual voltage of the first power supply P1, V2 is the actual voltage of the second power supply P2, U2 is the first detection voltage, U2' is the third detection voltage, U4 is the second detection voltage, U4' is the fourth detection voltage, R3 is the resistance of the third resistor RF3, R4 is the resistance of the fourth resistor RF4, and R5 is the resistance of the fifth resistor RF5.

[0073] As a result, when calculating the insulation resistance at the load end, there is no need to worry about the impact of the load's working mode, state, etc., which reduces misjudgment and improves the accuracy of the insulation system.

[0074] 4 , the voltage detection unit 30 may include: a first detection subunit 31 , a second detection subunit 32 , and a third detection subunit 33 ;

[0075] The first detection subunit 31 is connected to the first end of the second power switch PS2 and is configured to detect the voltage between the first power source P1 or the second power source P2 and the ground terminal GND;

[0076] The second detection sub-unit 32 is connected to the first end of the first power switch PS1 and the first end of the second power switch PS2, respectively, and is configured to detect the voltage of the first node N;

[0077] The third detection subunit 33 is connected to the positive terminal and the negative terminal respectively, and is configured to detect the voltage between the positive terminal and the negative terminal.

[0078] 3 , the first detection subunit 31 may include:

[0079] a first amplifier A1, wherein a first input terminal of the first amplifier A1 is connected to a first terminal of the second power switch PS2, and a second input terminal of the first amplifier A1 is connected to an output terminal of the first amplifier A1;

[0080] The second amplifier A2 has a first input connected to the output of the first amplifier A1 , a second input connected to the first reference voltage supply terminal, and an output of the second amplifier A2 serving as the output of the first detection subunit 31 .

[0081] It should be noted that the first amplifier A1 plays the role of a voltage follower, but the input voltage of the voltage follower needs to meet the range of -5V to 5V, that is, the first reference voltage supply end needs to meet the range of -5V to 5V. The second amplifier A2 plays the role of a subtractor, which is responsible for further subtracting and amplifying the previous stage voltage.

[0082] 3 , the second detection subunit 32 may include a third amplifier A3 and a fourth amplifier A4 .

[0083] In this example, a third amplifier A3, a first input terminal of the third amplifier A3 is connected to the first node N, and a second input terminal of the third amplifier A3 is connected to the output terminal of the third amplifier A3;

[0084] The fourth amplifier A4 has a first input connected to the output of the third amplifier A3 , a second input connected to the second reference voltage supply terminal, and an output of the fourth amplifier A4 serving as the output of the second detection subunit 32 .

[0085] Specifically, the positive power supply terminals of the first, second, third, and fourth amplifiers A1, A2, A3, and A4 can be connected to a 5V voltage. The third amplifier A3 functions as a voltage follower, but its input voltage must be between -5V and 5V. In other words, the second reference voltage supply terminal must be between -5V and 5V. The fourth amplifier A4 functions as a subtractor, further subtracting and amplifying the previous voltage. Thirdly, the positive power supply terminals of the first, second, third, and fourth amplifiers A1, A2, A3, and A4 can be connected to a 5V voltage.

[0086] The third detection subunit 33 adopts the structure of the first detection subunit 31 or the structure of the second detection subunit 32. For example, the third detection subunit 33 includes: a first amplifier A1, wherein the first input terminal of the first amplifier A1 is connected to the positive terminal, and the second input terminal of the first amplifier A1 is connected to the output terminal of the first amplifier A1; a second amplifier A2, wherein the first input terminal of the second amplifier A2 is connected to the output terminal of the first amplifier A1, the second input terminal of the second amplifier A2 is connected to the first reference voltage supply terminal, and the output terminal of the second amplifier A2 serves as the output terminal of the third detection subunit 33.

[0087] It should be noted that the first amplifier A1 plays the role of a voltage follower, but the input voltage of the voltage follower needs to meet the range of -5V to 5V, that is, the first reference voltage supply end needs to meet the range of -5V to 5V. The second amplifier A2 plays the role of a subtractor, which is responsible for further subtracting and amplifying the previous stage voltage.

[0088] 3 , the voltage detection unit 30 may further include:

[0089] An AD (Analogue to Digital conversion) conversion module 34 is provided. The first AD sampling terminal AINP_A of the AD conversion module 34 is connected to the output terminal of the first detection sub-unit 31 to perform AD sampling on the detection voltage output by the first detection sub-unit 31. The second AD sampling terminal AINP_B of the AD conversion module 34 is connected to the output terminal of the second detection sub-unit 32 to perform AD sampling on the detection voltage output by the second detection sub-unit 32.

[0090] Specifically, the first AD sampling terminal AINP_A of the AD conversion module 34 is connected to the output terminal of the second amplifier A2 to perform AD sampling on the detection voltage output by the first detection subunit 31. The second AD sampling terminal AINP_B of the AD conversion module 34 is connected to the output terminal of the fourth amplifier A4 to perform AD sampling on the detection voltage output by the second detection subunit 32. It should be noted that the AD conversion module 34 converts analog signals into digital signals and can be an AD port of an MCU (Motor Control Unit) or a dedicated AD conversion chip.

[0091] 3 , the insulation detection circuit 100 may further include: a total positive switch K1 and a total negative switch K2;

[0092] Among them, one end of the total positive switch K1 is connected to the positive electrode of battery B, and the other end of the total positive switch K1 is connected to the positive electrode of load L; one end of the total negative switch K2 is connected to the negative electrode of load L, and the other end of the total negative switch K2 is connected to the negative electrode of battery B;

[0093] When the object to be measured is the battery B, the total positive switch K1 and the total negative switch K2 are both closed; when the object to be measured is the load L, the total positive switch K1 and the total negative switch K2 are both open.

[0094] In summary, the insulation detection circuit 100 can predict the insulation resistance of the load end in advance when both the main positive switch and the main negative switch are disconnected, so as to facilitate the vehicle end to detect vehicles with poor insulation in advance, achieve the effect of early warning, and improve the safety and reliability of the vehicle; when calculating the insulation resistance of the load end, there is no need to worry about the influence of the load's working mode, state, etc., thereby reducing misjudgment and improving the accuracy of the insulation system; through the differential operation of the supply voltage of the first power supply and the supply voltage of the second power supply, it can effectively reduce the error caused by external interference, improve the robustness of the system, and enhance the anti-interference ability.

[0095] The present disclosure also provides a battery management system.

[0096] FIG5 is a schematic diagram of a battery management system according to an embodiment of the present disclosure. As shown in FIG5 , the battery management system includes the insulation detection circuit 100 described above.

[0097] According to the battery management system of the embodiment of the present disclosure, the insulation resistance of the ground terminal can be detected through the insulation detection circuit regardless of whether the power supply unit is connected to the positive terminal or the negative terminal of the load.

[0098] The present disclosure also provides a vehicle.

[0099] Figure 6 is a schematic diagram of a vehicle according to an embodiment of the present disclosure. As shown in Figure 6 , the vehicle includes the battery management system described above.

[0100] According to the vehicle of the embodiment of the present disclosure, through the battery management system, the insulation resistance of the ground terminal can be detected regardless of whether the power supply unit is connected to the positive terminal or the negative terminal of the load.

[0101] FIG7 is a flow chart of an insulation detection method according to an embodiment of the present disclosure. The insulation detection method is applied to a battery management system, which includes a power supply unit 10 and a switching unit 20. The power supply unit 10 is adapted to provide a first power supply P1 and a second power supply P2, wherein the first power supply P1 and the second power supply P2 have different supply voltages. The switching unit 20 is adapted to switch the power supply unit 10 between the positive terminal of a load L and the negative terminal of the load L. As shown in FIG4 , the insulation detection method includes the following steps:

[0102] S201, detecting the voltage between the first power source P1 and the ground terminal GND, and detecting the voltage between the second power source P2 and the ground terminal GND;

[0103] S202. Determine the insulation resistance according to the detected voltage.

[0104] It should be noted that for other specific implementations of the insulation detection method of the embodiment of the present disclosure, reference may be made to the specific implementation of the insulation detection circuit 100 of the above embodiment of the present disclosure.

[0105] Therefore, this insulation detection method can predict the insulation resistance of the load end in advance when both the main positive switch and the main negative switch are disconnected, which is convenient for the vehicle end to detect vehicles with poor insulation in advance, achieves the effect of early warning, and improves the safety and reliability of the vehicle; when calculating the insulation resistance of the load end, there is no need to worry about the influence of the load's working mode, state, etc., which reduces misjudgment and improves the accuracy of the insulation system; through the differential operation of the supply voltage of the first power supply and the supply voltage of the second power supply, it can effectively reduce the error caused by external interference, improve the robustness of the system, and enhance the anti-interference ability.

[0106] It should be noted that the logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, apparatus, or device (such as a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device), or in conjunction with such instruction execution system, apparatus, or device. For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transmit a program for use by an instruction execution system, apparatus, or device, or in conjunction with such instruction execution system, apparatus, or device. More specific examples (non-exhaustive list) of computer-readable media include the following: an electrical connection portion having one or more wires (electronic device), a portable computer disk cartridge (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and programmable read-only memory (EPROM or flash memory), fiber optic devices, and portable compact disc read-only memory (CDROM). Furthermore, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or otherwise processing it in a suitable manner if necessary, and then storing it in a computer memory.

[0107] It should be understood that various parts of the present disclosure can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used to implement: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0108] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present disclosure. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0109] In the description of the present disclosure, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation to the present disclosure.

[0110] In addition, the terms "first" and "second" used in the embodiments of the present disclosure are only used for descriptive purposes and should not be understood as indicating or implying relative importance, or implicitly indicating the number of technical features indicated in the embodiments. Therefore, the features defined in the embodiments of the present disclosure with terms such as "first" and "second" can explicitly or implicitly indicate that the embodiment includes at least one such feature. In the description of the present disclosure, the word "plurality" means at least two or two or more, such as two, three, four, etc., unless otherwise clearly and specifically defined in the embodiments.

[0111] In this disclosure, unless otherwise clearly specified or limited in the embodiments, the terms "installed," "connected," "connect," and "fixed" appearing in the embodiments should be understood in a broad sense. For example, the connection can be a fixed connection, a detachable connection, or an integral connection. It can also be a mechanical connection, an electrical connection, etc.; of course, it can also be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication between two elements, or the interaction between two elements. For those skilled in the art, the specific meanings of the above terms in this disclosure can be understood based on the specific implementation.

[0112] In the present disclosure, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0113] Although the embodiments of the present disclosure have been shown and described above, it is understood that the above embodiments are illustrative and are not to be construed as limitations on the present disclosure. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present disclosure.

Claims

1. An insulation detection circuit, characterized in that: The insulation detection circuit (100) comprises: A power supply unit (10) adapted to provide a first power supply and a second power supply, wherein the first power supply and the second power supply have different supply voltages; A switching unit (20) adapted to switch the power supply unit (10) to be connected to the positive terminal of a load or the negative terminal of the load; A voltage detection unit (30) is configured to detect the voltage between the first power supply and the ground terminal, and to detect the voltage between the second power supply and the ground terminal; The voltage detected by the voltage detection unit (30) is used to determine the insulation resistance.

2. The insulation detection circuit according to claim 1, characterized in that: The voltage detection unit (30) is configured to: when the power supply unit (10) is connected to the positive terminal, If the power supply unit (10) provides the first power supply, the voltage between the first power supply and the ground terminal is detected to obtain a first detection voltage; If the power supply unit (10) provides the second power supply, the voltage between the second power supply and the ground terminal is detected to obtain a second detection voltage; The voltage detection unit (30) is further configured to, when the power supply unit (10) is connected to the negative terminal, If the power supply unit (10) provides the first power supply, the voltage between the first power supply and the ground terminal is detected to obtain a third detection voltage; If the power supply unit (10) provides the second power supply, the voltage between the second power supply and the ground terminal is detected to obtain a fourth detection voltage; The first detection voltage to the fourth detection voltage are used to determine the insulation resistance of the positive terminal to the ground terminal and the insulation resistance of the negative terminal to the ground terminal.

3. The insulation detection circuit according to claim 2, characterized in that: The insulation detection circuit (100) further comprises a first resistor and a second resistor; one end of the first resistor is connected to the positive terminal; one end of the second resistor is respectively connected to the other end of the first resistor and the voltage detection unit (30) and has a first node; the other end of the second resistor is respectively connected to the ground terminal and the voltage detection unit (30); the voltage detection unit (30) is further configured as follows: When the power supply unit (10) is connected to the positive terminal and the power supply unit (10) provides the first power supply, detecting the voltage of the first node to obtain a fifth detection voltage; When the power supply unit (10) is connected to the positive terminal and the power supply unit (10) provides the second power In the case of the voltage of the first node being detected, a sixth detection voltage is obtained; Among them, the fifth detection voltage and the first detection voltage are used to determine the actual voltage of the first power supply, the sixth detection voltage and the second detection voltage are used to determine the actual voltage of the second power supply, the actual voltage of the first power supply, the actual voltage of the second power supply, the first detection voltage and the second detection voltage are used to determine the insulation resistance of the positive terminal to the ground terminal, and the actual voltage of the first power supply, the actual voltage of the second power supply, the third detection voltage and the fourth detection voltage are used to determine the insulation resistance of the negative terminal to the ground terminal.

4. The insulation detection circuit according to claim 3, characterized in that: The voltage detection unit (30) is further configured to: If the power supply unit (10) is connected to the positive terminal and the power supply unit (10) provides the first power supply, the voltage between the positive terminal and the negative terminal is detected to obtain a seventh detection voltage; If the power supply unit (10) is connected to the negative terminal and the power supply unit (10) provides the first power supply, the voltage between the positive terminal and the negative terminal is detected to obtain an eighth detection voltage; Among them, the first detection voltage, the third detection voltage, the actual voltage of the first power supply, the seventh detection voltage and the eighth detection voltage are used to determine the insulation resistance of the positive terminal to the ground terminal and the insulation resistance of the negative terminal to the ground terminal when the load connected between the positive terminal and the negative terminal is in the power generation mode.

5. The insulation detection circuit according to claim 4, characterized in that: The voltage detection unit (30) is further configured to: If the power supply unit (10) is connected to the positive terminal and the power supply unit (10) provides the second power supply, the voltage between the positive terminal and the negative terminal is detected to obtain a ninth detection voltage; If the power supply unit (10) is connected to the negative terminal and the power supply unit (10) provides the second power supply, the voltage between the positive terminal and the negative terminal is detected to obtain a tenth detection voltage; Among them, the second detection voltage, the fourth detection voltage, the actual voltage of the second power supply, the ninth detection voltage and the tenth detection voltage are used to determine the insulation resistance of the positive terminal to the ground terminal and the insulation resistance of the negative terminal to the ground terminal when the load is in the power generation mode.

6. The insulation detection circuit according to any one of claims 3 to 5, characterized in that: The switching unit (20) comprises: a switching switch, wherein a first end of the switching switch is connected to a first end of the power supply unit (10), a second end of the switching switch is connected to the positive terminal via a third resistor, and a third end of the switching switch is connected to the negative terminal via a fourth resistor.

7. The insulation detection circuit according to claim 6, characterized in that: The power supply unit (10) comprises: the first power supply, the second power supply, a first power switch and a second power switch; The first end of the first power switch is connected to the first end of the switching switch, and the second end of the first power switch is connected to the first end of the switching switch. The first power switch is connected to the negative electrode of the first power supply, and the third end of the first power switch is connected to the negative electrode of the second power supply; A first end of the second power switch is connected to the ground end through a fifth resistor, a second end of the second power switch is connected to the positive electrode of the first power supply, and a third end of the second power switch is connected to the positive electrode of the second power supply.

8. The insulation detection circuit according to claim 7, characterized in that: The voltage detection unit (30) comprises: a first detection subunit (31), a second detection subunit (32) and a third detection subunit (33); The first detection subunit (31) is connected to the first end of the second power switch and is configured to detect the voltage between the first power source or the second power source and the ground terminal; The second detection subunit (32) is connected to the first end of the first power switch and the first end of the second power switch respectively, and is configured to detect the voltage of the first node; The third detection subunit (33) is connected to the positive terminal and the negative terminal respectively, and is configured to detect the voltage between the positive terminal and the negative terminal.

9. The insulation detection circuit according to claim 8, characterized in that: The first detection subunit (31) comprises: a first amplifier, wherein a first input terminal of the first amplifier is connected to a first terminal of the second power switch, and a second input terminal of the first amplifier is connected to an output terminal of the first amplifier; A second amplifier, wherein a first input end of the second amplifier is connected to an output end of the first amplifier, a second input end of the second amplifier is connected to a first reference voltage supply end, and an output end of the second amplifier serves as an output end of the first detection subunit (31).

10. The insulation detection circuit according to claim 8 or 9, characterized in that: The second detection subunit (32) comprises: a third amplifier, wherein a first input terminal of the third amplifier is connected to the first node, and a second input terminal of the third amplifier is connected to an output terminal of the third amplifier; A fourth amplifier, wherein a first input terminal of the fourth amplifier is connected to an output terminal of the third amplifier, a second input terminal of the fourth amplifier is connected to a second reference voltage supply terminal, and an output terminal of the fourth amplifier serves as an output terminal of the second detection subunit (32).

11. The insulation detection circuit according to claim 8, 9 or 10, characterized in that: The voltage detection unit (30) further comprises: An AD conversion module, wherein a first AD sampling end of the AD conversion module is connected to an output end of the first detection subunit (31) so as to perform AD sampling on a detection voltage output by the first detection subunit (31), and a second AD sampling end of the AD conversion module is connected to an output end of the second detection subunit (32) so as to perform AD sampling on the detection voltage output by the second detection subunit (32).

12. The insulation detection circuit according to claim 5, characterized in that: The insulation detection circuit (100) further comprises: The controller (40) is configured to determine that the load connected between the positive terminal and the negative terminal is in a power generation mode when the seventh detection voltage and the ninth detection voltage are respectively greater than a first preset voltage, or when the eighth detection voltage and the tenth detection voltage are respectively greater than a second preset voltage.

13. The insulation detection circuit according to claim 12, characterized in that: The controller (40) is further configured to: If the first voltage change rate determined based on the seventh detection voltage and the ninth detection voltage is less than the first preset change rate, the insulation resistance of the positive terminal to the ground terminal and the insulation resistance of the negative terminal to the ground terminal are determined according to the first detection voltage, the third detection voltage, the actual voltage of the first power supply, the seventh detection voltage and the eighth detection voltage; If the second voltage change rate determined based on the eighth detection voltage and the tenth detection voltage is less than a second preset change rate, the insulation resistance of the positive terminal to the ground terminal and the insulation resistance of the negative terminal to the ground terminal are determined according to the second detection voltage, the fourth detection voltage, the actual voltage of the second power supply, the ninth detection voltage and the tenth detection voltage.

14. A battery management system, characterized in that: The invention comprises the insulation detection circuit (100) as claimed in any one of claims 1 to 13.

15. A vehicle, characterized in that: The vehicle includes the battery management system of claim 14.

16. An insulation detection method, characterized in that: Applied to a battery management system, the battery management system comprises a power supply unit (10) and a switching unit (20), the power supply unit (10) is suitable for providing a first power supply and a second power supply, wherein the first power supply and the second power supply have different supply voltages, the switching unit (20) is suitable for switching the power supply unit (10) to be connected to the positive terminal of a load or the negative terminal of the load, and the method comprises: Detecting a voltage between the first power supply and a ground terminal, and detecting a voltage between the second power supply and the ground terminal; Determine the insulation resistance based on the detected voltage.

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