Insulation Detection Method and Insulation Detection System

Abstract

The present application provides an insulation detection method and an insulation detection system, including: when a vehicle's complete insulation detection mode start signal is detected, the bridge measurement circuit is controlled to perform two balance calibrations and obtain measurement data; based on the initial balance state of the bridge measurement circuit, the first resistance value of the standard adjustable resistor in the bridge measurement circuit is obtained, and the first insulation resistance ratio is calculated; based on the secondary balance state of the bridge measurement circuit, the second resistance value of the standard adjustable resistor is obtained, and the second insulation resistance ratio is calculated; by combining the first insulation resistance ratio and the second insulation resistance ratio, the insulation resistance value corresponding to each insulation resistor is calculated; it is determined whether the insulation resistance value meets the preset safety threshold, and if not, an alarm message is generated. In this method, through the two bridge balance calibration methods, combined with the vehicle state adaptive detection mode, the insulation detection method can be dynamically adjusted under different working conditions to ensure measurement accuracy while reducing power consumption.

Description

Technical Field

[0001] The present application relates to the technical field of electric vehicles, and in particular to an insulation detection method and an insulation detection system. Background Art

[0002] With the widespread use of electric vehicles, the safety of high-voltage battery systems has become an important factor affecting the stability of vehicle operation and the safety of personnel. Especially in scenarios such as high-speed driving, fast charging and low-power operation, the vehicle's high-voltage system needs to monitor the insulation status in real time to prevent leakage faults from posing a safety threat to personnel and equipment.

[0003] Existing insulation detection methods mainly include the single bridge balancing method and the signal injection method. The single bridge balancing method adjusts the parameters of the bridge measurement circuit to make the bridge reach a balance once and then calculates the insulation resistance, but the measurement error is large and it cannot adapt to complex working conditions. The signal injection method detects the insulation status by injecting low-frequency or high-frequency signals into the high-voltage system, but it may affect the normal operation of the battery management system, and the calculation is complex and the power consumption is high, so it is not suitable for long-term online monitoring. Some systems use timed detection, but they cannot adaptively adjust the detection mode according to the vehicle status, resulting in increased power consumption or decreased detection accuracy. Summary of the invention

[0004] In view of this, the purpose of the present application is to provide an insulation detection method and an insulation detection system. Through two bridge balance calibration methods and combined with a vehicle state adaptive detection mode, the insulation detection mode can be dynamically adjusted under different working conditions to ensure measurement accuracy while reducing power consumption.

[0005] In a first aspect, the present invention provides an insulation detection method, which is applied to a controller of an insulation control system; the insulation control system also includes an insulation detection module connected to the controller; the insulation detection module includes a high-voltage battery module, an insulation impedance circuit and a bridge measurement circuit connected in sequence; the insulation impedance circuit includes two insulation resistors; the method includes: when a complete insulation detection mode start signal of the vehicle is detected, controlling the bridge measurement circuit to perform two balance calibrations and obtain measurement data; based on an initial balance state of the bridge measurement circuit, obtaining a first resistance value of a standard adjustable resistor in the bridge measurement circuit, and calculating a first insulation resistance ratio; based on a secondary balance state of the bridge measurement circuit, obtaining a second resistance value of the standard adjustable resistor, and calculating a second insulation resistance ratio; by combining the first insulation resistance ratio and the second insulation resistance ratio, calculating the insulation resistance value corresponding to each insulation resistor; judging whether the insulation resistance value meets a preset safety threshold, and if not, generating an alarm message.

[0006] In an alternative embodiment, the insulation detection module further includes a zero-adjusting and amplifying circuit connected to the bridge measurement circuit; the zero-adjusting and amplifying circuit is connected to the controller; the steps of controlling the bridge measurement circuit to perform two balance calibrations and obtaining measurement data include: sending a disconnection signal to the positive switch and the negative switch of the bridge measurement circuit to make the bridge measurement circuit in an open state; adjusting the standard adjustable resistor until the voltage output signal output by the zero-adjusting and amplifying circuit is 0, determining that the bridge measurement circuit reaches the initial balance state, and recording the first resistance value corresponding to the initial balance state; determining the bridge balance ratio based on the ratio of the first resistance value to the bridge reference resistance value of the bridge measurement circuit; judging whether the bridge balance ratio is greater than a preset standard value; if the bridge balance ratio is greater than the preset standard value, sending a closing signal to the positive switch to make the bridge measurement circuit enter the positive insulation detection mode; otherwise, sending a closing signal to the negative switch to make the bridge measurement circuit enter the negative insulation detection mode; adjusting the standard adjustable resistor until the voltage output signal sent by the zero-adjusting and amplifying circuit is 0 again, determining that the bridge measurement circuit reaches the secondary balance state, and recording the second resistance value corresponding to the secondary balance state.

[0007] In an alternative embodiment, the insulation resistance includes a positive insulation resistance and a negative insulation resistance; the steps of obtaining the first resistance value of the standard adjustable resistor in the bridge measurement circuit based on the initial balance state of the bridge measurement circuit and calculating the first insulation resistance ratio include: when the bridge measurement circuit reaches the initial balance state, calculating the ratio of the positive insulation resistance value of the positive insulation resistance to the negative insulation resistance value of the negative insulation resistance as the first insulation resistance ratio; wherein, the first insulation resistance ratio is equal to the ratio of the bridge reference resistance value to the first resistance value.

[0008] In an alternative embodiment, the insulation resistance includes a positive insulation resistance and a negative insulation resistance; the second insulation resistance ratio includes a positive insulation resistance ratio and a negative insulation resistance ratio; when the bridge measurement circuit is in the positive insulation detection mode, based on the secondary balance state of the bridge measurement circuit, obtaining the second resistance value of the standard adjustable resistor and calculating the second insulation resistance ratio includes: when the bridge measurement circuit reaches the secondary balance state, calculating the ratio of the positive insulation resistance value to the positive parallel equivalent resistance value of the first voltage-dividing resistor in the bridge measurement circuit; calculating the ratio of the positive parallel equivalent resistance value to the negative insulation resistance value as the positive insulation resistance ratio; wherein, the positive insulation resistance ratio is equal to the ratio of the bridge reference resistance value to the second resistance value; when the bridge measurement circuit is in the negative insulation detection mode, based on the secondary balance state of the bridge measurement circuit, obtaining the second resistance value of the standard adjustable resistor and calculating the second insulation resistance ratio includes: when the bridge measurement circuit reaches the secondary balance state, calculating the ratio of the negative insulation resistance value to the negative parallel equivalent resistance value of the second voltage-dividing resistor in the bridge measurement circuit; calculating the ratio of the positive insulation resistance value to the negative parallel equivalent resistance value as the negative insulation resistance ratio; wherein, the negative insulation resistance ratio is equal to the ratio of the bridge reference resistance value to the second resistance value.

[0009] In an alternative embodiment, before the step of controlling the bridge measurement circuit to perform two balance calibrations and obtaining measurement data when a complete insulation detection mode start signal of the vehicle is detected, the method further includes: obtaining the operating state data of the vehicle; when the operating state data is for uniform driving or low-speed driving or parking waiting, determining that the vehicle enters the complete insulation detection mode; when the operating state data is for acceleration or braking or high-speed driving, determining that the vehicle enters the quick detection mode; when the operating state data is for long-distance driving or low load or low SOC mode, determining that the vehicle enters the low-power consumption detection mode; when the operating state data is for fast charging state, determining that the vehicle enters the complete insulation detection mode.

[0010] In an alternative embodiment, the high-voltage battery module includes a high-voltage battery; after the step of determining that the vehicle enters the quick detection mode when the operating state data is for high-speed driving, the method further includes: obtaining the voltage to ground of the high-voltage battery at the current moment and the voltage to ground at the previous moment; wherein, the voltage to ground includes the positive voltage to ground and the negative voltage to ground; calculating the voltage change amplitude between the voltage to ground at the current moment and the voltage to ground at the previous moment; determining whether the voltage change amplitude is greater than a preset voltage amplitude; if the voltage change amplitude is greater than the preset voltage amplitude, adjusting the vehicle to enter the complete insulation detection mode; if the voltage change amplitude is less than or equal to the preset voltage amplitude, keeping the vehicle in the quick detection mode.

[0011] In an optional embodiment, the controller is connected to the battery management system; when the operating status data is long-distance driving or low load or low SOC mode, the step of determining whether the vehicle enters a low power consumption detection mode includes: if abnormal detection information sent by the battery management system is received, adjusting the vehicle to enter a complete insulation detection mode; or, if the current operating status data is different from the previous operating status data, adjusting the vehicle to enter a complete insulation detection mode.

[0012] In a second aspect, the present invention provides an insulation detection system, comprising: an insulation detection module, and also comprising a controller of any one of the aforementioned embodiments; the controller is connected to the insulation detection module; the insulation detection module comprises a high-voltage battery module, an insulation impedance circuit and a bridge measurement circuit connected in sequence; the insulation impedance circuit comprises two insulation resistors; the controller is used to control the bridge measurement circuit to perform two balance calibrations and obtain measurement data when a complete insulation detection mode start signal of the vehicle is detected; the controller is also used to obtain a first resistance value of a standard adjustable resistor in the bridge measurement circuit based on an initial balance state of the bridge measurement circuit, and calculate a first insulation resistance ratio; obtain a second resistance value of the standard adjustable resistor based on a secondary balance state of the bridge measurement circuit, and calculate a second insulation resistance ratio; calculate the insulation resistance value corresponding to each insulation resistor by combining the first insulation resistance ratio and the second insulation resistance ratio; determine whether the insulation resistance value meets a preset safety threshold, and if not, generate an alarm message.

[0013] In an optional embodiment, the high-voltage battery module includes a high-voltage battery; the bridge measurement circuit includes a standard adjustable resistor, a bridge reference resistor, a positive switch, a negative switch, a first voltage-dividing resistor and a second voltage-dividing resistor; the first end of the first voltage-dividing resistor is connected to the positive electrode of the high-voltage battery, and the second end is connected to the positive switch; the first end of the second voltage-dividing resistor is connected to the negative switch, and the second end is connected to the negative electrode of the high-voltage battery; the first end of the bridge reference resistor is connected to the positive electrode of the high-voltage battery, and the second end is connected to the first end of the standard adjustable resistor; the second end of the standard adjustable resistor is connected to the negative electrode of the high-voltage battery; the second end of the positive switch is connected to the first end of the negative switch to form a bridge structure; the connection point between the bridge reference resistor and the standard adjustable resistor is the first midpoint; the connection point between the positive switch and the negative switch is the second midpoint, and the second midpoint is grounded.

[0014] In an alternative embodiment, the insulation detection system further includes a zero-adjusting amplifier circuit; the zero-adjusting amplifier circuit includes a first operational amplifier, a second operational amplifier, a third operational amplifier, a first resistor, a second resistor, a third resistor, and a fourth resistor; the positive input terminal of the first operational amplifier is connected to the first midpoint; the positive input terminal of the second operational amplifier is connected to the second midpoint; the first end of the first resistor is connected to the output terminal of the first operational amplifier, and the second end of the first resistor and the first end of the second resistor are both connected to the positive input terminal of the third operational amplifier; the second end of the second resistor and the output terminal of the third operational amplifier are both connected to the controller; the first end of the third resistor is connected to the output terminal of the second operational amplifier, and the second end of the third resistor and the first end of the fourth resistor are both connected to the negative input terminal of the third operational amplifier; the second end of the fourth resistor is connected to the controller.

[0015] In an alternative embodiment, the insulation resistance includes a positive insulation resistance and a negative insulation resistance; the positive insulation resistance is connected to the positive electrode of the high-voltage battery; the negative insulation resistance is connected to the negative electrode of the high-voltage battery; the midpoint of the connection line between the positive insulation resistance and the negative insulation resistance is grounded.

[0016] In an alternative embodiment, the insulation detection system further includes an acoustic and optical alarm module; the acoustic and optical alarm module is connected to the controller.

[0017] The embodiment of the present application provides an insulation detection method and an insulation detection system, wherein the insulation control system further comprises an insulation detection module connected to a controller; the insulation detection module comprises a high-voltage battery module, an insulation impedance circuit and a bridge measurement circuit connected in sequence; the insulation impedance circuit comprises two insulation resistors; the method comprises: when a complete insulation detection mode start signal of the vehicle is detected, the bridge measurement circuit is controlled to perform two balance calibrations and obtain measurement data; based on the initial balance state of the bridge measurement circuit, the first resistance value of the standard adjustable resistor in the bridge measurement circuit is obtained, and the first insulation resistance ratio is calculated; based on the secondary balance state of the bridge measurement circuit, the second resistance value of the standard adjustable resistor is obtained, and the second insulation resistance ratio is calculated; by combining the first insulation resistance ratio and the second insulation resistance ratio, the insulation resistance value corresponding to each insulation resistor is calculated; it is determined whether the insulation resistance value meets the preset safety threshold, and if not, an alarm message is generated. In this method, by performing two balance calibrations on the bridge measurement circuit and obtaining two sets of resistance data of the standard adjustable resistor, the accurate values ​​of the positive electrode insulation resistance and the negative electrode insulation resistance can be calculated, and it is determined whether the preset safety threshold is met, thereby improving the accuracy of insulation detection and ensuring the safety of the high-voltage system of the electric vehicle. By adaptively selecting the complete detection mode, fast detection mode or low-power detection mode under different vehicle operating conditions, the computing resource usage can be reduced and the system power consumption can be reduced, thereby taking into account both detection efficiency and endurance performance and optimizing vehicle energy consumption management. By using the zero-adjustment amplifier circuit to amplify the gain and adjust the zero-point deviation of the bridge measurement signal, the accuracy of the insulation resistance calculation can be improved, and the system's anti-interference ability can be enhanced, so that the insulation state can still be stably detected under complex working conditions, improving the safety and reliability of the battery management system.

[0018] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or understood by practicing the present application. The purpose and other advantages of the present application are realized and obtained by the structures specifically pointed out in the description, claims and drawings.

[0019] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1Flowchart of the insulation detection method provided by the embodiment of the present application;

[0022] Figure 2 Schematic diagram of the insulation detection system provided by the embodiment of the present application;

[0023] Figure 3 Schematic diagram of the insulation detection module provided by the embodiment of the present application;

[0024] Figure 4 Schematic diagram of another insulation detection system provided by the embodiment of the present application.

[0025] Icon: 1 - Insulation detection module; 2 - Controller; 3 - Acousto-optic alarm module; 11 - High-voltage battery module; 12 - Insulation impedance circuit; 13 - Bridge measurement circuit; 14 - Zero-adjusting amplifier circuit; - Standard adjustable resistor; - Bridge reference resistor; - Positive pole switch; - Negative pole switch; - First voltage-dividing resistor; - Second voltage-dividing resistor; X - First midpoint; O - Second midpoint; - Positive pole insulation resistor; - Negative pole insulation resistor; BT - High-voltage battery; - First operational amplifier; - Second operational amplifier; - Third operational amplifier; - First resistor; - Second resistor; - Third resistor; - Fourth resistor; - Fifth resistor; - Sixth resistor; - Seventh resistor. Detailed implementation manners

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions of the present application will be clearly and completely described below with reference to the accompanying drawings. Apparently, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the protection scope of the present application.

[0027] For the convenience of understanding this embodiment, the embodiments of the present application will be introduced in detail below.

[0028] Embodiment 1:

[0029] Figure 1Flowchart of the insulation detection method provided by the embodiment of the present application.

[0030] The insulation detection method is applied to the controller of the insulation control system; the insulation control system further includes an insulation detection module connected to the controller; the insulation detection module includes a high-voltage battery module, an insulation impedance circuit, and a bridge measurement circuit connected in sequence; the insulation impedance circuit includes two insulation resistors.

[0031] Here, the controller is an MCU (Microcontroller Unit), which is responsible for detecting the process, calculating the insulation resistance, and triggering an alarm.

[0032] The insulation detection module is used to collect data and measure the insulation state of the battery to the ground.

[0033] The high-voltage battery module includes a high-voltage battery, which is used as the detection object to ensure the safety of the battery to the ground.

[0034] The insulation impedance circuit reflects the insulation state through two insulation resistors.

[0035] The bridge measurement circuit obtains accurate measurement data through two balance calibrations so that the controller can calculate the insulation resistance.

[0036] Refer to Figure 1 , the insulation detection method includes:

[0037] Step S101, when a complete insulation detection mode start signal of the vehicle is detected, control the bridge measurement circuit to perform two balance calibrations and obtain measurement data.

[0038] Here, the controller determines whether a start signal of the complete insulation detection mode is received.

[0039] If the detection mode is triggered, the controller sends an instruction to the bridge measurement circuit to start the insulation detection process. Check the state of the bridge measurement circuit, read the voltage signal of the current bridge measurement circuit, and ensure that the system is not in the measurement process. If the bridge is not in the open state, perform a forced reset (disconnect the positive switch and the negative switch).

[0040] In one embodiment, the insulation detection module further includes a zero-adjustment and amplification circuit connected to the bridge measurement circuit; the zero-adjustment and amplification circuit is connected to the controller.

[0041] Here, the zero-adjustment and amplification circuit is used to improve the stability and accuracy of the measurement signal and ensure the accuracy and reliability of the insulation resistance value calculated by the controller.

[0042] The steps of step S101 include the following steps S201-S206.

[0043] Step S201: Send a disconnection signal to the positive switch and negative switch of the bridge measurement circuit to make the bridge measurement circuit in an open state.

[0044] Here, the controller sends a disconnection instruction to the bridge measurement circuit to disconnect the positive switch and negative switch, ensuring that the bridge measurement circuit is not directly connected to the high-voltage battery, so as to correctly adjust the bridge parameters.

[0045] After waiting for the bridge measurement circuit to stabilize, read the output signal of the bridge and confirm that it is disconnected to avoid errors caused by voltage hysteresis.

[0046] Step S202: Adjust the standard adjustable resistor until the voltage output signal output by the zero-adjusting amplifier circuit is 0, determine that the bridge measurement circuit reaches the initial balance state, and record the first resistance value corresponding to the initial balance state.

[0047] Here, the bridge measurement circuit includes a standard adjustable resistor, a bridge reference resistor, a positive switch, a negative switch, a first voltage-dividing resistor, and a second voltage-dividing resistor; the first end of the first voltage-dividing resistor is connected to the positive pole of the high-voltage battery, and the second end is connected to the positive switch; the first end of the second voltage-dividing resistor is connected to the negative switch, and the second end is connected to the negative pole of the high-voltage battery; the first end of the bridge reference resistor is connected to the positive pole of the high-voltage battery, and the second end is connected to the first end of the standard adjustable resistor; the second end of the standard adjustable resistor is connected to the negative pole of the high-voltage battery; the second end of the positive switch is connected to the first end of the negative switch to form a bridge structure; the connection point between the bridge reference resistor and the standard adjustable resistor is the first midpoint; the connection point between the positive switch and the negative switch is the second midpoint, and the second midpoint is grounded.

[0048] Adjust the standard adjustable resistor, gradually change the resistance value of the standard adjustable resistor, and determine the voltage difference between the second midpoint and the first midpoint by obtaining the voltage output signal of the zero-adjusting amplifier circuit.

[0049] If the output voltage of the zero-adjusting amplifier circuit is 0, it indicates that the bridge reaches the initial balance state, and record the resistance value of the standard adjustable resistor at this time as the first resistance value.

[0050] Step S203: Determine the bridge balance ratio based on the ratio of the first resistance value to the bridge reference resistance value of the bridge measurement circuit.

[0051] Here, the first resistance value is and the bridge reference resistance value is and the bridge balance ratio is .

[0052] Step S204: Determine whether the bridge balance ratio is greater than a preset standard value.

[0053] Here, the preset standard value is determined based on the vehicle insulation safety standard and can be set to 1.

[0054] Step S205, if the bridge balance ratio is greater than the preset standard value, send a closing signal to the positive switch to make the bridge measurement circuit enter the positive insulation detection mode; otherwise, send a closing signal to the negative switch to make the bridge measurement circuit enter the negative insulation detection mode.

[0055] Here, if , it indicates that the positive insulation resistance is large and positive insulation measurement is required. If , it indicates that the negative insulation resistance is large and negative insulation measurement is required.

[0056] Step S206, adjust the standard adjustable resistor until the voltage output signal sent by the zero-adjusting amplifier circuit becomes 0 again, determine that the bridge measurement circuit reaches the secondary balance state, and record the second resistance value corresponding to the secondary balance state.

[0057] Here, under the selected measurement path (positive insulation detection mode or negative insulation detection mode), readjust the standard adjustable resistor, gradually change the resistance value of the standard adjustable resistor, and observe the change of the voltage output signal.

[0058] If the voltage output signal of the zero-adjusting amplifier circuit becomes 0 again, it indicates that the bridge reaches the second balance state. Record the resistance value of the standard adjustable resistor at this time as the second resistance value.

[0059] In an embodiment, before step S101, the method further includes:

[0060] Obtain the operation state data of the vehicle.

[0061] Here, the operation state data includes vehicle speed information for determining whether the vehicle is in a high-speed, low-speed, or stopped state. Acceleration information for detecting whether the vehicle is in an accelerating or braking state. Power system load for determining the battery load condition, such as whether it enters the low-power mode. Battery management system status information including state of charge and charging status of the battery. Whether the driving mode signal is in an energy-saving mode, a sports mode, etc. Whether the external environment information is connected to a charging pile (charging gun status), whether it is in a high-temperature or low-temperature environment.

[0062] The controller selects a suitable insulation detection mode based on the above data.

[0063] Further, when the operation state data is for uniform driving, low-speed driving, or parking waiting, it is determined that the vehicle enters the complete insulation detection mode.

[0064] Here, when the operation state data indicates that the vehicle is in uniform driving, low-speed driving, or parking waiting, it enters the complete insulation detection mode.

[0065] Specifically, for a vehicle traveling at a constant speed, the vehicle speed is greater than or equal to 60 km / h. At this time, the vehicle runs stably, without severe current fluctuations, and a complete bridge calibration is performed to obtain high-precision insulation detection data. The insulation detection frequency can be once every 1 - 5 minutes.

[0066] For low-speed driving, the vehicle speed is less than 60 km / h. Low-speed driving involves frequent starts and stops, resulting in changes in the insulation state. The insulation detection frequency can be once every minute.

[0067] For parking and waiting, the vehicle speed = 0, such as waiting for a red light, entering a parking mode, pre-charging detection, etc. The insulation detection frequency is once every 30 seconds.

[0068] Furthermore, when the operating state data is acceleration or braking or high-speed driving, it is determined that the vehicle enters the fast detection mode.

[0069] Here, if it is detected that the vehicle is in a state of rapid acceleration, the current changes violently, resulting in short-term fluctuations in the insulation state. The fast detection mode is adopted to reduce the calculation burden and avoid affecting the vehicle's power system. The insulation detection frequency can be once every 10 minutes (or longer).

[0070] When the vehicle recovers energy (kinetic energy recovery or braking), the direction of the battery current changes, affecting the insulation measurement. The fast detection mode is adopted to preferentially detect the battery voltage to ground. The insulation detection frequency can be once every 10 minutes (or longer).

[0071] For high-speed driving, the vehicle speed is greater than or equal to 120 km / h. The vehicle is in a high-speed cruise mode, and it is required to reduce the calculation burden of the MCU and avoid affecting power management. Only the battery voltage to ground is detected to reduce the calculation burden of the complete bridge measurement. A complete detection is triggered when there is an abnormal voltage fluctuation.

[0072] In one embodiment, after the step of determining that the vehicle enters the fast detection mode when the operating state data is high-speed driving, the method further includes the following steps S301 - S305:

[0073] Step S301, obtain the voltage to ground of the high-voltage battery at the current moment and the voltage to ground at the previous moment; wherein, the voltage to ground includes the positive-pole voltage to ground and the negative-pole voltage to ground.

[0074] Here, based on a preset sampling time interval, for example, sampling is performed once every 100 ms. A detection window (such as 1 s or 10 s) is set for calculating the voltage fluctuation trend.

[0075] Read the voltage of the positive pole of the high-voltage battery relative to the vehicle body ground and the voltage of the negative pole of the high-voltage battery relative to the vehicle body ground.

[0076] Read the voltage of the positive electrode of the high-voltage battery relative to the vehicle body ground and the voltage of the negative electrode of the high-voltage battery relative to the vehicle body ground at the last detection stored.

[0077] Step S302, calculate the voltage change amplitude between the voltage to the ground at the current moment and the voltage to the ground at the previous moment.

[0078] Here, calculate the voltage change amplitude of the positive electrode to the ground and the voltage change amplitude of the negative electrode to the ground, and select the maximum voltage change amplitude between the voltage change amplitude of the positive electrode to the ground and the voltage change amplitude of the negative electrode to the ground to measure the voltage fluctuation degree of the high-voltage battery and determine whether to enter the complete detection mode.

[0079] Step S303, judge whether the voltage change amplitude is greater than the preset voltage amplitude.

[0080] Here, the preset voltage amplitude can be set to 5% - 10% of the rated voltage. For example, if the rated voltage of the battery system is 800V, the preset voltage amplitude can be set to 40V.

[0081] Step S304, if the voltage change amplitude is greater than the preset voltage amplitude, adjust the vehicle to enter the complete insulation detection mode.

[0082] Here, if it is detected that the voltage change amplitude to the ground is greater than the threshold value, adjust to the complete detection mode to perform more accurate insulation measurement.

[0083] After entering the complete detection mode, increase the detection frequency, such as performing it once every 30 seconds, instead of once every 10 minutes in the fast mode.

[0084] Step S305, if the voltage change amplitude is less than or equal to the preset voltage amplitude, keep the vehicle in the fast detection mode.

[0085] Here, if the voltage change does not exceed the threshold value, the vehicle remains in the fast detection mode to reduce the calculation burden and improve the detection efficiency.

[0086] Furthermore, when the operating state data is in the long-distance driving or low-load or low-SOC mode, determine that the vehicle enters the low-power consumption detection mode.

[0087] Here, long-distance driving means that the vehicle is in a continuous high-speed running state, and the vehicle runs at a stable speed for a long time, and high-frequency insulation detection is not required. Adopt the low-power consumption detection mode to reduce the detection frequency and reduce the calculation burden of the MCU.

[0088] If it is detected that the battery load is low (cruising, low-speed uniform driving), the detection frequency is reduced.

[0089] The low SOC mode means that the SOC (State of Charge) of the vehicle is lower than 10%, and the vehicle enters the energy-saving mode to reduce the MCU computing tasks and avoid affecting the endurance.

[0090] The low-power detection mode only performs detection when the battery management system triggers a request or detects a change in the vehicle state. The detection frequency of the low-power detection mode can be once every 30 minutes for long-distance driving and once every 1 hour for high-speed driving.

[0091] In one embodiment, the controller is connected to the battery management system.

[0092] Here, the controller is connected to the battery management system to obtain battery status data and decide whether to adjust the insulation detection mode.

[0093] The controller establishes a connection with the battery management system through the CAN bus or other communication protocols and listens to the battery health status sent by the battery management system.

[0094] Read the insulation status data monitored by the battery management system and determine whether there is an abnormality.

[0095] Obtain the abnormal events recorded by the battery management system, such as short-term leakage, abnormal temperature, abnormal current, etc.

[0096] Obtain the battery management system monitoring data related to the insulation status, including high-voltage system leakage monitoring, battery voltage, current, temperature, remaining power, insulation monitoring historical data, and diagnostic trouble codes.

[0097] When the operating state data is long-distance driving or low load or low SOC mode, the steps to determine that the vehicle enters the low-power detection mode include:

[0098] If the abnormal detection information sent by the battery management system is received, adjust the vehicle to enter the complete insulation detection mode.

[0099] Here, if the abnormal detection information of the battery management system is received, immediately exit the low-power detection mode and adjust the vehicle to enter the complete insulation detection mode. Among them, the abnormal detection information can be at least one of the following: insulation impedance drop (the insulation impedance value drops below the safety threshold), battery short-term leakage detection (transient leakage phenomenon), abnormal temperature (the battery or high-voltage harness temperature exceeds the safety range), charge and discharge abnormality (overcharge, over-discharge, abnormal current fluctuation).

[0100] Or, if the current operating state data is different from the previous operating state data, adjust the vehicle to enter the complete insulation detection mode.

[0101] Here, if the vehicle operating state data changes, the low-power consumption mode is exited and the full detection mode is entered to ensure real-time update of the insulation state.

[0102] Obtain the current operating state data, including vehicle speed, acceleration, battery load, charging state, etc., and compare the current state data with the data at the previous moment.

[0103] Specifically, if the vehicle speed suddenly changes from 80 km / h to 120 km / h and enters the high-speed mode, it is necessary to adjust to the full detection mode.

[0104] If the acceleration changes drastically (such as emergency braking or rapid acceleration), affecting the insulation state, a full detection is required.

[0105] If the battery load increases sharply (such as entering the high-power output mode), it is necessary to fully detect the insulation situation.

[0106] If the operating state data changes significantly, the low-power consumption detection mode is exited:

[0107] Furthermore, when the operating state data is in the fast charging state, it is determined that the vehicle enters the full insulation detection mode.

[0108] Here, a full insulation detection is performed before fast charging to ensure no insulation hidden danger before high-voltage fast charging and avoid potential leakage risks caused by high-voltage charging. The detection is performed once every 10 seconds to ensure the stability of the insulation state during the charging process. If a decrease in insulation is detected, the charging power is reduced and the user is notified to check the vehicle state.

[0109] Step S102, based on the initial balanced state of the bridge measurement circuit, obtain the first resistance value of the standard adjustable resistor in the bridge measurement circuit and calculate the first insulation resistance ratio.

[0110] In one embodiment, the insulation resistance includes a positive pole insulation resistance and a negative pole insulation resistance.

[0111] The steps of step S102 include:

[0112] When the bridge measurement circuit reaches the initial balanced state, calculate the ratio of the positive pole insulation resistance value of the positive pole insulation resistance and the negative pole insulation resistance value of the negative pole insulation resistance as the first insulation resistance ratio; wherein, the first insulation resistance ratio is equal to the ratio of the bridge reference resistance value and the first resistance value.

[0113] Here, the positive pole insulation resistance is the insulation resistance between the positive pole of the high-voltage battery and the ground, which mainly affects the leakage of the high-voltage positive pole line.

[0114] The negative pole insulation resistance is the insulation resistance between the negative pole of the high-voltage battery and the ground, which affects the insulation state of the high-voltage negative pole line.

[0115] In the initial balanced state, the balance relationship of the bridge is shown in the following formula (1):

[0116] (1)

[0117] Wherein, is the bridge reference resistance (fixed value), is the first resistance value, is the first insulation resistance ratio.

[0118] Step S103: Based on the secondary balanced state of the bridge measurement circuit, obtain the second resistance value of the standard adjustable resistor and calculate the second insulation resistance ratio.

[0119] In one embodiment, the insulation resistance includes a positive insulation resistance and a negative insulation resistance; the second insulation resistance ratio includes a positive insulation resistance ratio and a negative insulation resistance ratio.

[0120] When the bridge measurement circuit is in the positive insulation detection mode, the steps of step S103 include the following steps S401 - S402:

[0121] Step S401: When the bridge measurement circuit reaches the secondary balanced state, calculate the positive insulation resistance value and the positive parallel equivalent resistance value of the first voltage - dividing resistor in the bridge measurement circuit.

[0122] Here, the positive parallel equivalent resistance value is shown in the following formula (2):

[0123] (2)

[0124] Wherein, is the positive parallel equivalent resistance value, is the first voltage - dividing resistor.

[0125] Step S402: Calculate the ratio of the positive parallel equivalent resistance value to the negative insulation resistance value as the positive insulation resistance ratio; wherein, the positive insulation resistance ratio is equal to the ratio of the bridge reference resistance value to the second resistance value.

[0126] Here, the positive insulation resistance ratio is: , where the corresponding relationship between the positive insulation resistance ratio, the bridge reference resistance value and the second resistance value is shown in the following formula (3):

[0127] (3)

[0128] Wherein, is the second resistance value.

[0129] In one embodiment, when the bridge measurement circuit is in the negative electrode insulation detection mode, the steps of step S103 include the following steps S501-S502:

[0130] Step S501, when the bridge measurement circuit reaches a secondary equilibrium state, the negative electrode insulation resistance value and the negative electrode parallel equivalent resistance value of the second voltage-dividing resistor in the bridge measurement circuit are calculated.

[0131] Here, the negative electrode parallel equivalent resistance value is shown in the following formula (4):

[0132] (4)

[0133] in, is the negative electrode parallel equivalent resistance value, is the second voltage dividing resistor.

[0134] Step S502, calculating the ratio of the positive electrode insulation resistance value to the negative electrode parallel equivalent resistance value as the negative electrode insulation resistance ratio; wherein the negative electrode insulation resistance ratio is equal to the ratio of the bridge reference resistance value to the second resistance value.

[0135] Here, the negative electrode insulation resistance ratio is: , where the corresponding relationship between the negative electrode insulation resistance ratio and the bridge reference resistance value and the second resistance value is shown in the following formula (5):

[0136] (5)

[0137] Step S104, calculating the insulation resistance value corresponding to each insulation resistor by combining the first insulation resistance ratio and the second insulation resistance ratio.

[0138] Here, when the bridge measurement circuit is in the positive insulation detection mode, the following formula (6) can be obtained by combining formula (1) and formula (3):

[0139] (6)

[0140] Substituting this into formula (7), we can obtain the following formula:

[0141] (7)

[0142] When the bridge measurement circuit is in positive insulation detection mode, formula (1) and formula (5) are combined and substituted into formula (6), the following formula (8) can be obtained:

[0143] (8)

[0144] Step S105, determining whether the insulation resistance value meets a preset safety threshold, and if not, generating an alarm message.

[0145] Here, the preset safety threshold is pre-set according to the actual situation and can be set to ×Working voltage.

[0146] when or When both are greater than the preset safety threshold, the insulation status is normal.

[0147] when or When any value is greater than the preset safety threshold, the insulation fault alarm is triggered, and the controller sends a warning signal to the battery management system and stores the fault information. At the same time, the sound and light alarm module is triggered to notify the driver to check the insulation status. In fast charging mode, if insulation degradation is detected, the charging power is reduced and the user is notified.

[0148] The embodiment of the present application provides an insulation detection method, which is applied to a controller of an insulation control system; the insulation control system also includes an insulation detection module connected to the controller; the insulation detection module includes a high-voltage battery module, an insulation impedance circuit and a bridge measurement circuit connected in sequence; the insulation impedance circuit includes two insulation resistors; the method includes: when a complete insulation detection mode start signal of the vehicle is detected, the bridge measurement circuit is controlled to perform two balance calibrations and obtain measurement data; based on the initial balance state of the bridge measurement circuit, the first resistance value of the standard adjustable resistor in the bridge measurement circuit is obtained, and the first insulation resistance ratio is calculated; based on the secondary balance state of the bridge measurement circuit, the second resistance value of the standard adjustable resistor is obtained, and the second insulation resistance ratio is calculated; by combining the first insulation resistance ratio and the second insulation resistance ratio, the insulation resistance value corresponding to each insulation resistor is calculated; it is determined whether the insulation resistance value meets the preset safety threshold, and if not, an alarm message is generated. In this method, by performing two balance calibrations on the bridge measurement circuit and obtaining two sets of resistance data of the standard adjustable resistor, the accurate values ​​of the positive electrode insulation resistance and the negative electrode insulation resistance can be calculated, and it is determined whether the preset safety threshold is met, thereby improving the accuracy of insulation detection and ensuring the safety of the high-voltage system of the electric vehicle. By adaptively selecting the complete detection mode, fast detection mode or low-power detection mode under different vehicle operating conditions, the computing resource usage can be reduced and the system power consumption can be reduced, thereby taking into account both detection efficiency and endurance performance and optimizing vehicle energy consumption management. By using the zero-adjustment amplifier circuit to amplify the gain and adjust the zero-point deviation of the bridge measurement signal, the accuracy of the insulation resistance calculation can be improved, and the system's anti-interference ability can be enhanced, so that the insulation state can still be stably detected under complex working conditions, improving the safety and reliability of the battery management system.

[0149] Embodiment 2:

[0150] Figure 2 Schematic diagram of the insulation detection system provided in an embodiment of the present application.

[0151] Reference Figure 2 The insulation detection system includes: an insulation detection module 1, and also includes the above-mentioned controller 2; the controller 2 is connected to the insulation detection module 1; the insulation detection module 1 includes a high-voltage battery module 11, an insulation impedance circuit 12 and a bridge measurement circuit 13 connected in sequence; the insulation impedance circuit 12 includes two insulation resistors.

[0152] The controller 2 is used to control the bridge measurement circuit 13 to perform two balance calibrations and obtain measurement data when a complete insulation detection mode start signal of the vehicle is detected;

[0153] The controller 2 is also used to obtain the standard adjustable resistance in the bridge measurement circuit 13 based on the initial balance state of the bridge measurement circuit 13. The first resistance value , and calculate the first insulation resistance ratio; based on the secondary balance state of the bridge measurement circuit 13, obtain the standard adjustable resistance The second resistance value , and calculate the second insulation resistance ratio; by combining the first insulation resistance ratio and the second insulation resistance ratio, calculate the insulation resistance value corresponding to each insulation resistance; determine whether the insulation resistance value meets the preset safety threshold, and if not, generate an alarm message.

[0154] In one embodiment, referring to Figure 3 The high-voltage battery module 11 includes a high-voltage battery BT; the bridge measurement circuit 13 includes a standard adjustable resistor , bridge reference resistance , positive switch , Negative switch , the first voltage divider resistor and the second voltage divider resistor .

[0155] Here, the negative pole of the high-voltage battery BT is grounded GND, which is used to provide a high-voltage power supply, simulate the high-voltage system of the electric vehicle, and serve as the power input terminal of the insulation detection to measure the insulation condition of the high-voltage battery to the ground.

[0156] The first voltage divider resistor The first end is connected to the positive electrode of the high-voltage battery BT, and the second end is connected to the positive switch .

[0157] The second voltage divider resistor The first terminal is connected to the negative switch , and the second end is connected to the negative electrode of the high-voltage battery BT.

[0158] Bridge reference resistor The first end is connected to the positive terminal of the high-voltage battery BT, and the second end is connected to the standard adjustable resistor The first end; standard adjustable resistor The second end is connected to the negative electrode of the high-voltage battery BT.

[0159] Positive electrode switch The second end of is connected to the negative electrode switch The first end to form a bridge structure.

[0160] Bridge reference resistor And the standard adjustable resistor The connection point between them is the first midpoint X.

[0161] Positive electrode switch And the negative electrode switch The connection point between them is the second midpoint O, and the second midpoint O is grounded.

[0162] Here, the second midpoint O is used to measure the potential difference on both sides of the bridge, and the voltage at this point , monitored by the controller 2, determines whether the bridge reaches the balanced state and adjusts the standard adjustable resistor .

[0163] Positive electrode switch And the negative electrode switch Respectively control the switching of the bridge measurement circuit 13.

[0164] The voltage relationship between the first midpoint X and the second midpoint O can be expressed as: , where Is the voltage of the first midpoint, Is the voltage of the second midpoint, Is the voltage output signal. When the bridge is in the balanced state, , which means , indicating that the insulation state is normal. That is, when , it indicates that the insulation state is normal. When , it indicates that there is an insulation fault.

[0165] In an embodiment, referring to Figure 3 , the insulation detection system further includes a zero-adjusting amplifier circuit 14; the zero-adjusting amplifier circuit 14 includes a first operational amplifier , a second operational amplifier , a third operational amplifier, a first resistor , a second resistor , a third resistor And a fourth resistor .

[0166] The positive input terminal of the first operational amplifier Is connected to the first midpoint; the positive input terminal of the second operational amplifier Is connected to the second midpoint.

[0167] The first resistor The first end of which is connected to the output end of the first operational amplifier The second end of the first resistor And the first end of the second resistor Are both connected to the positive input end of the third operational amplifier The second end of the second resistor And the output end of the third operational amplifier Are both connected to the controller

[0168] The third resistor The first end of which is connected to the output end of the second operational amplifier The second end of the third resistor And the first end of the fourth resistor Are both connected to the negative input end of the third operational amplifier The second end of the fourth resistor Is connected to the controller

[0169] Wherein, the fifth resistor Is connected between the output end and the negative input end of To form negative feedback, and is also connected to To transmit the amplified signal to Is used to stabilize The output of, prevent signal overload or distortion. Determine The gain of, adjust the amplification factor of the measurement signal, and improve the accuracy of insulation resistance calculation

[0170] The sixth resistor Is connected between the negative input end of And the negative input end of To form a differential input path, ensuring And Collect symmetric signals Is used to And The input voltages of are voltage-divided and matched so that it can correctly process the bridge measurement signal. Enhance the common-mode rejection ratio, improve the anti-noise ability, and reduce the influence of electromagnetic interference on the measurement signal

[0171] The seventh resistor Is connected between the output end and the negative input end of To form negative feedback, and is also connected to To transmit the amplified signal to Is used to control The gain of, ensure that its output signal is the same as ​​Form good symmetry and improve measurement accuracy. Form a negative feedback loop to prevent signal drift and improve the stability of the amplifier circuit.

[0172] Here, the zero-adjusting amplifier circuit 14 is used to improve the measurement signal accuracy, eliminate the zero-point error of the bridge measurement circuit, improve the detection accuracy through differential amplification, and reduce signal noise.

[0173] Operational amplifier 、 、 and resistors 、 、 、 constitute the zero-adjusting amplifier circuit, and and are added between the positive and negative buses of the high-voltage battery BT to form another set of bridge arms. In this way, the positive insulation resistance and the negative insulation resistance and and together constitute the four bridge arms of the DC bridge. The zero-adjusting amplifier circuit 14 detects the midpoint O and X of the bridge arms. The unbalanced voltage between point O and point X is amplified by the zero-adjusting amplifier circuit 14 to make the voltage measurement more accurate.

[0174] The zero-adjusting amplifier circuit 14 outputs the output signal and the reference voltage signal to the controller 2. Among them, represents the final detection result of the bridge measurement circuit 13 and is transmitted to the controller 2 for insulation state analysis. If the insulation resistance value is lower than the safety threshold, the controller 2 will trigger the alarm mechanism. is provided by the voltage division network composed of and and as the reference input of to compare whether the detection signal exceeds the safe range. If the deviation between and exceeds the normal range, it indicates that the insulation state is abnormal.

[0175] In one embodiment, referring to Figure 3 , the insulation resistance includes the positive insulation resistance and the negative insulation resistance ; the positive insulation resistance is connected to the positive pole of the high-voltage battery BT; the negative insulation resistance is connected to the negative pole of the high-voltage battery BT.

[0176] The positive insulation resistance and the negative insulation resistance The midpoint of the connection line is grounded.

[0177] Here, the positive insulation resistance Connects the positive pole of the high-voltage battery BT to the first voltage-dividing resistor .

[0178] The negative insulation resistance Connects the negative pole of the high-voltage battery BT to the second voltage-dividing resistor .

[0179] In one embodiment, referring to Figure 4 , the insulation detection system further includes an acoustic-optic alarm module 3; the acoustic-optic alarm module 3 is connected to the controller 2.

[0180] The embodiment of the present application provides an insulation detection system. In this way, by adopting the two-time balance calibration method of the bridge measurement circuit and combining the signal processing ability of the zero-adjusting amplifier circuit, the positive insulation resistance and the negative insulation resistance can be accurately measured, improving the accuracy and stability of the insulation detection, thereby ensuring the safety of the high-voltage battery system and dynamically adjusting the detection mode under different operating states (such as high-speed driving, fast charging, low load, etc.) to optimize the vehicle energy consumption management.

[0181] The computer program product provided by the embodiment of the present application includes a computer-readable storage medium storing program codes, and the instructions included in the program codes can be used to execute the methods described in the foregoing method embodiments. For specific implementation, reference can be made to the method embodiments, which will not be elaborated herein.

[0182] Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working processes of the systems and devices described above can refer to the corresponding processes in the foregoing method embodiments, which will not be elaborated herein.

[0183] In addition, in the description of the embodiments of the present application, unless otherwise clearly specified and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.

[0184] When the above-mentioned functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of this application. The aforementioned storage medium includes: various media that can store program codes, such as USB flash drives, mobile hard disks, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), magnetic disks, or optical discs.

[0185] In the description of this application, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to this application. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0186] Finally, it should be noted that: the above-mentioned embodiments are only specific implementation manners of this application, used to illustrate the technical solutions of this application, rather than limiting it. The protection scope of this application is not limited thereto. Although this application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: any person skilled in the art within the technical scope disclosed in this application can still modify the technical solutions recorded in the foregoing embodiments, or can easily think of changes, or make equivalent replacements for some of the technical features; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be covered within the protection scope of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claims.

Claims

1. An insulation detection method, characterized in that: A controller applied to an insulation control system; the insulation control system further comprises an insulation detection module connected to the controller; the insulation detection module comprises a high-voltage battery module, an insulation impedance circuit and a bridge measurement circuit connected in sequence; the insulation impedance circuit comprises two insulation resistors; the insulation resistors comprise a positive insulation resistor and a negative insulation resistor; the method comprises: When a complete insulation detection mode start signal of the vehicle is detected, the bridge measurement circuit is controlled to perform two balance calibrations and obtain measurement data; Based on the initial equilibrium state of the bridge measurement circuit, a first resistance value of a standard adjustable resistor in the bridge measurement circuit is obtained, and a first insulation resistance ratio is calculated; wherein the first insulation resistance ratio is a ratio of a positive insulation resistance value of the positive insulation resistor to a negative insulation resistance value of the negative insulation resistor; Based on the secondary balance state of the bridge measurement circuit, obtaining a second resistance value of the standard adjustable resistor, and calculating a second insulation resistance ratio; Calculating the insulation resistance value corresponding to each of the insulation resistors by combining the first insulation resistance ratio and the second insulation resistance ratio; Determine whether the insulation resistance value meets a preset safety threshold, and if not, generate an alarm message; The second insulation resistance ratio includes a positive electrode insulation resistance ratio and a negative electrode insulation resistance ratio; When the bridge measurement circuit is in the positive electrode insulation detection mode, based on the secondary balance state of the bridge measurement circuit, the steps of obtaining the second resistance value of the standard adjustable resistor and calculating the second insulation resistance ratio include: When the bridge measurement circuit reaches the secondary equilibrium state, calculating the positive electrode insulation resistance value of the positive electrode insulation resistor and the positive electrode parallel equivalent resistance value of the first voltage-dividing resistor in the bridge measurement circuit; Calculate the positive electrode insulation resistance ratio by calculating the ratio of the positive electrode parallel equivalent resistance value to the negative electrode insulation resistance value of the negative electrode; When the bridge measurement circuit is in the negative electrode insulation detection mode, based on the secondary balance state of the bridge measurement circuit, the steps of obtaining the second resistance value of the standard adjustable resistor and calculating the second insulation resistance ratio include: When the bridge measurement circuit reaches the secondary equilibrium state, calculating the negative electrode insulation resistance value and the negative electrode parallel equivalent resistance value of the second voltage-dividing resistor in the bridge measurement circuit; The ratio of the positive electrode insulation resistance value to the negative electrode parallel equivalent resistance value is calculated as the negative electrode insulation resistance ratio.

2. The insulation detection method according to claim 1, characterized in that: The insulation detection module also includes a zero adjustment amplifier circuit connected to the bridge measurement circuit; the zero adjustment amplifier circuit is connected to the controller; The steps of controlling the bridge measurement circuit to perform two balance calibrations and obtaining measurement data include: Sending a disconnect signal to the positive switch and the negative switch of the bridge measurement circuit to put the bridge measurement circuit in an open circuit state; Adjusting the standard adjustable resistor until the voltage output signal output by the zero adjustment amplifier circuit is 0, determining that the bridge measurement circuit reaches the initial equilibrium state, and recording the first resistance value corresponding to the initial equilibrium state; determining a bridge balance ratio based on a ratio of the first resistance value to a bridge reference resistance value of the bridge measurement circuit; Determining whether the bridge balance ratio is greater than a preset standard value; If the bridge balance ratio is greater than the preset standard value, a closing signal is sent to the positive switch to make the bridge measurement circuit enter the positive insulation detection mode; otherwise, a closing signal is sent to the negative switch to make the bridge measurement circuit enter the negative insulation detection mode; The standard adjustable resistor is adjusted until the voltage output signal sent by the zero adjustment amplifier circuit is 0 again, determining that the bridge measurement circuit reaches the secondary balance state, and recording the second resistance value corresponding to the secondary balance state.

3. The insulation detection method according to claim 2, characterized in that: The step of obtaining a first resistance value of a standard adjustable resistor in the bridge measurement circuit based on an initial equilibrium state of the bridge measurement circuit and calculating a first insulation resistance ratio includes: When the bridge measurement circuit reaches the initial equilibrium state, the ratio of the positive insulation resistance value of the positive insulation resistance to the negative insulation resistance value of the negative insulation resistance is calculated as the first insulation resistance ratio; wherein the first insulation resistance ratio is equal to the ratio of the bridge reference resistance value to the first resistance value.

4. The insulation detection method according to claim 2, characterized in that: When the bridge measurement circuit is in the positive electrode insulation detection mode, the steps of obtaining the second resistance value of the standard adjustable resistor based on the secondary balance state of the bridge measurement circuit and calculating the second insulation resistance ratio include: The positive electrode insulation resistance ratio is equal to the ratio of the bridge reference resistance value to the second resistance value; When the bridge measurement circuit is in the negative electrode insulation detection mode, the steps of obtaining the second resistance value of the standard adjustable resistor based on the secondary balance state of the bridge measurement circuit and calculating the second insulation resistance ratio include: The negative electrode insulation resistance ratio is equal to the ratio of the bridge reference resistance value to the second resistance value.

5. The insulation detection method according to claim 1, characterized in that: When a complete insulation detection mode start signal of the vehicle is detected, before the step of controlling the bridge measurement circuit to perform two balance calibrations and obtaining measurement data, the method further includes: Acquiring running status data of the vehicle; When the running status data is uniform speed driving, low speed driving or parking waiting, determining that the vehicle enters the complete insulation detection mode; When the running state data is acceleration or braking or high-speed driving, determining that the vehicle enters a rapid detection mode; When the running state data is a long-distance driving or low-load or low-SOC mode, determining that the vehicle enters a low power consumption detection mode; When the operating status data is a fast charging state, it is determined that the vehicle enters the complete insulation detection mode.

6. The insulation detection method according to claim 5, characterized in that: The high-voltage battery module includes a high-voltage battery; When the running state data is high-speed driving, after determining that the vehicle enters a rapid detection mode, the method further includes: Obtaining the current voltage to ground of the high-voltage battery and the voltage to ground at the previous moment; wherein the voltage to ground includes a positive pole voltage to ground and a negative pole voltage to ground; Calculating a voltage change amplitude between the voltage to ground at the current moment and the voltage to ground at the previous moment; Determining whether the voltage variation amplitude is greater than a preset voltage amplitude; If the voltage variation amplitude is greater than the preset voltage amplitude, adjusting the vehicle to enter the complete insulation detection mode; If the voltage variation amplitude is less than or equal to the preset voltage amplitude, the vehicle is kept in the rapid detection mode.

7. The insulation detection method according to claim 5, characterized in that: The controller is connected to a battery management system; When the running state data is a long-distance driving or low-load or low SOC mode, the step of determining that the vehicle enters a low power consumption detection mode comprises: If the abnormal detection information sent by the battery management system is received, adjusting the vehicle to enter the complete insulation detection mode; or, If the current operating state data is different from the previous operating state data, the vehicle is adjusted to enter the complete insulation detection mode.

8. An insulation detection system, characterized in that: include: The insulation detection module further comprises the controller according to any one of claims 1 to 7; the controller is connected to the insulation detection module; the insulation detection module comprises a high-voltage battery module, an insulation impedance circuit and a bridge measurement circuit connected in sequence; the insulation impedance circuit comprises two insulation resistors; the insulation resistors comprise a positive insulation resistor and a negative insulation resistor; The controller is used to control the bridge measurement circuit to perform two balance calibrations and obtain measurement data when a complete insulation detection mode start signal of the vehicle is detected; The controller is further used to obtain a first resistance value of a standard adjustable resistor in the bridge measurement circuit based on an initial balance state of the bridge measurement circuit, and calculate a first insulation resistance ratio; wherein the first insulation resistance ratio is a ratio of a positive insulation resistance value of the positive insulation resistor to a negative insulation resistance value of the negative insulation resistor; based on a secondary balance state of the bridge measurement circuit, obtain a second resistance value of the standard adjustable resistor, and calculate a second insulation resistance ratio; calculate the insulation resistance value corresponding to each insulation resistor by combining the first insulation resistance ratio and the second insulation resistance ratio; determine whether the insulation resistance value meets a preset safety threshold, and if not, generate an alarm message; The second insulation resistance ratio includes a positive electrode insulation resistance ratio and a negative electrode insulation resistance ratio; The controller is further used to calculate the positive electrode insulation resistance value of the positive electrode insulation resistance and the positive electrode parallel equivalent resistance value of the first voltage divider resistor in the bridge measurement circuit when the bridge measurement circuit is in the positive electrode insulation detection mode and the bridge measurement circuit reaches the secondary equilibrium state; calculate the ratio of the positive electrode parallel equivalent resistance value to the negative electrode insulation resistance value of the negative electrode insulation resistance as the positive electrode insulation resistance ratio; The controller is also used to calculate the negative electrode insulation resistance value and the negative electrode parallel equivalent resistance value of the second voltage divider resistor in the bridge measurement circuit when the bridge measurement circuit is in the negative electrode insulation detection mode and the bridge measurement circuit reaches the secondary equilibrium state; and calculate the ratio of the positive electrode insulation resistance value to the negative electrode parallel equivalent resistance value as the negative electrode insulation resistance ratio.

9. The insulation detection system according to claim 8, characterized in that: The high-voltage battery module includes a high-voltage battery; the bridge measurement circuit includes a standard adjustable resistor, a bridge reference resistor, a positive switch, a negative switch, a first voltage-dividing resistor and a second voltage-dividing resistor; A first end of the first voltage-dividing resistor is connected to the positive electrode of the high-voltage battery, and a second end is connected to the positive electrode switch; A first end of the second voltage-dividing resistor is connected to the negative electrode switch, and a second end is connected to the negative electrode of the high-voltage battery; The first end of the bridge reference resistor is connected to the positive electrode of the high-voltage battery, and the second end is connected to the first end of the standard adjustable resistor; the second end of the standard adjustable resistor is connected to the negative electrode of the high-voltage battery; The second end of the positive switch is connected to the first end of the negative switch to form a bridge structure; The connection point between the bridge reference resistor and the standard adjustable resistor is a first midpoint; The connection point between the positive switch and the negative switch is a second midpoint, and the second midpoint is grounded.

10. The insulation detection system according to claim 9, characterized in that: The insulation detection system further includes a zero adjustment amplifier circuit; the zero adjustment amplifier circuit includes a first operational amplifier, a second operational amplifier, a third operational amplifier, a first resistor, a second resistor, a third resistor and a fourth resistor; The positive input terminal of the first operational amplifier is connected to the first midpoint; the positive input terminal of the second operational amplifier is connected to the second midpoint; The first end of the first resistor is connected to the output end of the first operational amplifier, the second end of the first resistor and the first end of the second resistor are both connected to the positive input end of the third operational amplifier; the second end of the second resistor and the output end of the third operational amplifier are both connected to the controller; The first end of the third resistor is connected to the output end of the second operational amplifier, the second end of the third resistor and the first end of the fourth resistor are both connected to the negative input end of the third operational amplifier; the second end of the fourth resistor is connected to the controller.

11. The insulation detection system according to claim 8, characterized in that: The insulation resistor includes a positive electrode insulation resistor and a negative electrode insulation resistor; the positive electrode insulation resistor is connected to the positive electrode of the high-voltage battery; the negative electrode insulation resistor is connected to the negative electrode of the high-voltage battery; The midpoint of the connection line between the positive electrode insulation resistor and the negative electrode insulation resistor is grounded.

12. The insulation detection system according to claim 8, characterized in that: The insulation detection system also includes an audible and visual alarm module; the audible and visual alarm module is connected to the controller.

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