Insulation detection method and insulation detection system

Abstract

The invention provides an insulation detection method and an insulation detection system, and the method comprises the steps: controlling a bridge measurement circuit to carry out two times of balance calibration when a complete insulation detection mode starting signal of a vehicle is detected, and obtaining measurement data; obtaining a first resistance value of a standard adjustable resistor in the bridge measurement circuit based on the initial balance state of the bridge measurement circuit, and calculating a first insulation resistance ratio; acquiring a second resistance value of the standard adjustable resistor based on a secondary balance state of the bridge measurement circuit, and calculating a second insulation resistance ratio; calculating an insulation resistance value corresponding to each insulation resistor by combining the first insulation resistance ratio and the second insulation resistance ratio; and judging whether the insulation resistance value accords with a preset safety threshold, and if not, generating alarm information. In the mode, through a two-time bridge balance calibration method and in combination with a vehicle state self-adaptive detection mode, the insulation detection mode can be dynamically adjusted under different working conditions, and the power consumption is reduced while the measurement precision is ensured.

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 adoption of electric vehicles, the safety of high-voltage battery systems has become a critical factor affecting vehicle operational stability and personnel safety. Especially in scenarios such as high-speed driving, fast charging, and low-power operation, the vehicle's high-voltage system requires real-time insulation monitoring 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 calculates the insulation resistance after adjusting the parameters of the bridge measurement circuit to achieve a single bridge balance. However, the measurement error is large and it cannot adapt to complex operating conditions. The signal injection method detects the insulation status by injecting low-frequency or high-frequency signals into the high-voltage system, but this may affect the normal operation of the battery management system. In addition, the calculation is complex and the power consumption is high, making it unsuitable for long-term online monitoring. Some systems use a timed detection method, but they cannot adaptively adjust the detection mode according to the vehicle status, resulting in increased power consumption or reduced detection accuracy. Summary of the Invention

[0004] In view of this, the purpose of this 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 method 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 the initial balance state of the bridge measurement circuit, obtaining the first resistance value of the standard adjustable resistor in the bridge measurement circuit, and calculating the first insulation resistance ratio; 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; 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 the preset safety threshold, and generating an alarm message if it does not meet the threshold.

[0006] In an optional embodiment, 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 obtain 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 resistance until the voltage output signal output by the zero adjustment amplifier circuit is 0, determining that the bridge measurement circuit has reached an initial balance state, and recording the first resistance value corresponding to the initial balance state; determining a 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 a positive insulation detection mode; otherwise, sending a closing signal to the negative switch to make the bridge measurement circuit enter a negative insulation detection mode; adjusting the standard adjustable resistance until the voltage output signal sent by the zero adjustment amplifier circuit is 0 again, determining that the bridge measurement circuit has reached a secondary balance state, and recording the second resistance value corresponding to the secondary balance state.

[0007] In an optional embodiment, the insulation resistance includes a positive electrode insulation resistance and a negative electrode insulation resistance; based on the initial equilibrium state of the bridge measurement circuit, obtaining the first resistance value of the standard adjustable resistor in the bridge measurement circuit, and calculating the first insulation resistance ratio step includes: when the bridge measurement circuit reaches the initial equilibrium state, calculating the ratio of the positive electrode insulation resistance value of the positive electrode insulation resistance to the negative electrode insulation resistance value of the negative electrode 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 optional embodiment, the insulation resistance includes a positive electrode insulation resistance and a negative electrode insulation resistance; 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 a positive electrode 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 step, including: when the bridge measurement circuit reaches a secondary balance state, calculating the positive electrode insulation resistance value and the positive electrode parallel equivalent resistance value of the first voltage divider resistor in the bridge measurement circuit; calculating the ratio of the positive electrode parallel equivalent resistance value to the negative electrode insulation resistance value as the positive electrode insulation resistance ratio; wherein , the positive electrode insulation resistance ratio is equal to the ratio of the bridge reference resistance value and the second resistance value; 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 second resistance value of the standard adjustable resistor is obtained, and the step of calculating the second insulation resistance ratio includes: when the bridge measurement circuit reaches the secondary balance state, calculating 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; calculating the ratio of the positive electrode insulation resistance value and 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 and the second resistance value.

[0009] In an optional embodiment, 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 before the step of obtaining measurement data, the method also includes: obtaining the vehicle's operating status data; when the operating status data is uniform speed driving, low speed driving, or parked waiting, determining that the vehicle enters the complete insulation detection mode; when the operating status data is acceleration, braking, or high speed driving, determining that the vehicle enters the fast detection mode; when the operating status data is long-distance driving, low load, or low SOC mode, determining that the vehicle enters the low power consumption detection mode; when the operating status data is fast charging state, determining that the vehicle enters the complete insulation detection mode.

[0010] In an optional embodiment, the high-voltage battery module includes a high-voltage battery; when the operating status data is high-speed driving, after determining that the vehicle enters the quick detection mode, the method also includes: obtaining the current ground voltage of the high-voltage battery and the ground voltage at the previous moment; wherein the ground voltage includes the positive pole ground voltage and the negative pole ground voltage; calculating the voltage change amplitude between the ground voltage at the current moment and the ground voltage at the previous moment; judging whether the voltage change amplitude is greater than the 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 the low power consumption detection mode includes: if 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 status data is different from the previous operating status data, adjusting the vehicle to enter the 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 generate an alarm message if it does not meet the threshold.

[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 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 positive 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.

[0014] In an optional embodiment, the insulation detection system also 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 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 optional embodiment, 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; and the midpoint of the connecting line between the positive electrode insulation resistor and the negative electrode insulation resistor is grounded.

[0016] In an optional embodiment, the insulation detection system further includes an audible and visual alarm module; the audible and visual alarm module is connected to the controller.

[0017] The present invention provides an insulation detection method and an insulation detection system. The insulation detection control system further includes an insulation detection module connected to a 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 vehicle complete insulation detection mode start signal is detected, controlling the bridge measurement circuit to perform two balance calibrations and obtain measurement data; based on the 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 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 insulation resistor by combining the first insulation resistance ratio and the second insulation resistance ratio; determining whether the insulation resistance value meets a preset safety threshold, and generating an alarm message if it does not meet the threshold. 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 and negative insulation resistances can be calculated, and whether the preset safety threshold is met can be determined, thereby improving the accuracy of insulation detection and ensuring the safety of the high-voltage system of the electric vehicle. By adaptively selecting full, fast, or low-power detection modes depending on the vehicle's operating conditions, computing resource usage and system power consumption can be reduced, thereby balancing detection efficiency and endurance, and optimizing vehicle energy management. A zero-adjustment amplifier circuit amplifies the bridge measurement signal's gain and adjusts its zero-point deviation, improving the accuracy of insulation resistance calculations and enhancing the system's anti-interference capabilities. This allows for stable insulation status detection even under complex operating conditions, enhancing 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 in part will become apparent from the description or be understood by practicing the present application. The objectives and other advantages of the present application are realized and obtained by the structures particularly 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 given below and described in detail with reference to the accompanying 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 following is a brief introduction to the drawings required for use in the specific implementation methods or the description of the prior art. 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 any creative work.

[0021] Figure 1A flow chart of the insulation detection method provided in an embodiment of the present application; Figure 2 Schematic diagram of the insulation detection system provided in an embodiment of the present application; Figure 3 A schematic diagram of an insulation detection module provided in an embodiment of the present application; Figure 4 A schematic diagram of another insulation detection system provided in an embodiment of the present application.

[0022] Icons: 1-Insulation detection module; 2-Controller; 3-Sound and light alarm module; 11-High voltage battery module; 12-Insulation impedance circuit; 13-Bridge measurement circuit; 14-Zero adjustment amplifier circuit; -Standard adjustable resistor; - bridge reference resistor; - Positive switch; -Negative switch; - a first voltage dividing resistor; - second voltage divider resistor; X- first midpoint; O- second midpoint; - Positive electrode insulation resistance; -Negative electrode insulation resistance; RT-high voltage battery; - a first operational amplifier; - a second operational amplifier; - a third operational amplifier; - a first resistor; - a second resistor; - a third resistor; - a fourth resistor; - a fifth resistor; - a sixth resistor; - Seventh resistor. DETAILED DESCRIPTION

[0023] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions of this application will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0024] To facilitate understanding of this embodiment, the embodiments of this application are described in detail below.

[0025] Example 1: Figure 1 This is a flow chart of the insulation detection method provided in an embodiment of the present application.

[0026] An insulation detection method 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.

[0027] Here, the controller is an MCU (Microcontroller Unit), which is responsible for detecting processes, calculating insulation resistance, and triggering alarms.

[0028] The insulation detection module is used to collect data and measure the insulation status of the battery to the ground.

[0029] The high-voltage battery module includes a high-voltage battery, which is used as a detection object to ensure the safety of the battery relative to the ground.

[0030] The insulation impedance circuit reflects the insulation status through two insulation resistors.

[0031] The bridge measurement circuit obtains accurate measurement data through two balanced calibrations to enable the controller to calculate the insulation resistance.

[0032] Reference Figure 1 , insulation detection methods include: Step S101 : When a vehicle complete insulation detection mode start signal is detected, the bridge measurement circuit is controlled to perform two balance calibrations and obtain measurement data.

[0033] Here, the controller determines whether a start signal for the complete insulation detection mode is received.

[0034] If the test mode is triggered, the controller sends a command to the bridge measurement circuit to begin the insulation test process. The controller then checks the bridge measurement circuit status and reads the current voltage signal to ensure the system is not in the measurement process. If the bridge is not in the open circuit state, a forced reset is performed (opening the positive and negative switches).

[0035] In one embodiment, the insulation detection module further includes a zero adjustment amplifier circuit connected to the bridge measurement circuit; the zero adjustment amplifier circuit is connected to the controller.

[0036] Here, the zero adjustment amplifier circuit is used to improve the stability and accuracy of the measurement signal, ensuring that the insulation resistance value calculated by the controller is accurate and reliable.

[0037] The steps of step S101 include the following steps S201-S206.

[0038] Step S201 : Sending a disconnect signal to the positive switch and the negative switch of the bridge measurement circuit to put the bridge measurement circuit into an open circuit state.

[0039] Here, the controller sends a disconnection instruction to the bridge measurement circuit to disconnect the positive switch and the negative switch, ensuring that the bridge measurement circuit is not directly connected to the high-voltage battery so that the bridge parameters can be correctly adjusted.

[0040] After the bridge measurement circuit stabilizes, read the bridge output signal to confirm that it is disconnected to avoid errors caused by voltage lag.

[0041] Step S202 , 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 an initial equilibrium state, and recording a first resistance value corresponding to the initial equilibrium state.

[0042] Here, the bridge measurement circuit includes a standard adjustable resistor, a bridge reference resistor, a positive switch, a negative switch, a first voltage divider resistor and a second voltage divider resistor; the first end of the first voltage divider 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 divider resistor is connected to the positive 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.

[0043] The standard adjustable resistor is adjusted to gradually change the resistance value of the standard adjustable resistor, and the voltage difference between the second midpoint and the first midpoint is determined by acquiring the voltage output signal of the zero adjustment amplifier circuit.

[0044] If the output voltage of the zero-adjusting amplifier circuit is 0, it indicates that the bridge has reached an initial equilibrium state. The resistance value of the standard adjustable resistor at this time is recorded as the first resistance value.

[0045] Step S203 : 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.

[0046] Here, the first resistor value is The bridge reference resistance is , the bridge balance ratio is .

[0047] Step S204 , determining whether the bridge balance ratio is greater than a preset standard value.

[0048] Here, the preset standard value is determined based on the vehicle insulation safety standard and can be set to 1.

[0049] Step S205: If the bridge balance ratio is greater than the preset standard value, a closing signal is sent to the positive switch to put the bridge measurement circuit into the positive insulation detection mode; otherwise, a closing signal is sent to the negative switch to put the bridge measurement circuit into the negative insulation detection mode.

[0050] Here, if , indicating that the positive insulation resistance is large, and positive insulation measurement is required. , indicating that the negative electrode insulation resistance is large and negative electrode insulation measurement is required.

[0051] Step S206 , adjusting the standard adjustable resistor until the voltage output signal sent by the zero adjustment amplifier circuit is 0 again, determining that the bridge measurement circuit has reached a secondary equilibrium state, and recording a second resistance value corresponding to the secondary equilibrium state.

[0052] 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 in the voltage output signal.

[0053] If the voltage output signal of the zero-adjustment amplifier circuit is 0 again, it indicates that the bridge has reached a second equilibrium state. The resistance value of the standard adjustable resistor at this time is recorded as the second resistance value.

[0054] In one embodiment, before step S101, the method further includes: Obtain vehicle operating status data.

[0055] Here, operating status data includes vehicle speed information, used to determine whether the vehicle is in a high-speed, low-speed, or stopped state. Acceleration information is used to detect whether the vehicle is accelerating or braking. Powertrain load is used to determine battery load conditions, such as whether it has entered low-power mode. Battery management system status information includes battery state of charge and charging status. Driving mode signals whether it is in energy-saving mode or sports mode. External environment information includes whether the charging station is connected (charging gun status) and whether the environment is hot or cold.

[0056] The controller selects the appropriate insulation detection mode based on the above data.

[0057] Furthermore, when the running status data is uniform speed driving, low speed driving, or parking waiting, it is determined that the vehicle enters the complete insulation detection mode.

[0058] Here, when the running status data indicates that the vehicle is traveling at a constant speed, traveling at a low speed, or parked and waiting, the complete insulation detection mode is entered.

[0059] Specifically, a constant speed driving condition is defined as a vehicle speed of ≥60 km / h. At this point, the vehicle is stable and there are no significant current fluctuations. A complete bridge calibration is performed to obtain high-precision insulation test data. The insulation test frequency can be performed every 1-5 minutes.

[0060] Low-speed driving refers to a vehicle speed less than 60 km / h. Low-speed driving involves frequent starts and stops, which causes changes in insulation status. The insulation test frequency can be performed once every minute.

[0061] When the vehicle is parked and waiting, the speed is 0, for example, when waiting for a red light, entering parking mode, or performing a pre-fast charge test. The insulation test frequency is once every 30 seconds.

[0062] Furthermore, when the running status data is acceleration or braking or high-speed driving, it is determined that the vehicle enters the fast detection mode.

[0063] If the vehicle is detected to be accelerating rapidly, the current may fluctuate dramatically, causing short-term fluctuations in insulation status. Rapid detection mode is used to reduce the computational burden and avoid impacting the vehicle's powertrain. Insulation testing can be performed every 10 minutes (or longer).

[0064] When the vehicle recovers energy (either through kinetic energy recovery or braking), the battery current direction changes, affecting insulation measurement. Use the fast test mode to prioritize the battery-to-ground voltage. Insulation testing can be performed every 10 minutes (or longer).

[0065] High-speed driving refers to vehicle speeds ≥120 km / h, when the vehicle is in high-speed cruise mode. This requires reducing the MCU's computational burden to avoid impacting power management. Testing only the battery-to-ground voltage reduces the computational burden of a complete bridge measurement. A complete test is triggered when the voltage fluctuates abnormally.

[0066] In one embodiment, when the operating status data indicates high-speed driving, after determining that the vehicle enters the rapid detection mode, the method further includes the following steps S301-S305: Step S301 , 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 the positive electrode voltage to ground and the negative electrode voltage to ground.

[0067] Here, based on a preset sampling time interval, for example, sampling is performed every 100 ms, and a detection window (such as 1 s or 10 s) is set to calculate the voltage fluctuation trend.

[0068] Read the current voltage of the high-voltage battery's positive electrode relative to the vehicle body ground and the voltage of the high-voltage battery's negative electrode relative to the vehicle body ground.

[0069] The stored voltage of the high-voltage battery positive electrode relative to the vehicle body ground and the voltage of the high-voltage battery negative electrode relative to the vehicle body ground at the time of the last detection are read.

[0070] Step S302 , calculating the voltage variation between the voltage to ground at the current moment and the voltage to ground at the previous moment.

[0071] Here, the positive pole-to-ground voltage change amplitude and the negative pole-to-ground voltage change amplitude are calculated, and the maximum voltage change amplitude of the positive pole-to-ground voltage change amplitude and the negative pole-to-ground voltage change amplitude are selected to measure the fluctuation degree of the high-voltage battery-to-ground voltage and determine whether it is necessary to enter the full detection mode.

[0072] Step S303: determine whether the voltage variation range is greater than a preset voltage range.

[0073] Here, the preset voltage amplitude can be set to 5% to 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.

[0074] Step S304: If the voltage variation is greater than the preset voltage variation, the vehicle is adjusted to enter a complete insulation detection mode.

[0075] Here, if the voltage change amplitude to ground is detected to be greater than a threshold, the system switches to the full detection mode to perform more accurate insulation measurement.

[0076] After entering full detection mode, increase the detection frequency to, for example, every 30 seconds instead of every 10 minutes in quick mode.

[0077] Step S305: If the voltage variation is less than or equal to the preset voltage variation, the vehicle is kept in the rapid detection mode.

[0078] Here, if the voltage change does not exceed the threshold, the vehicle remains in the fast detection mode to reduce the computational burden and improve detection efficiency.

[0079] Furthermore, when the operating status data is a long-distance driving or low-load or low SOC mode, it is determined that the vehicle enters a low power consumption detection mode.

[0080] Here, long-distance driving means the vehicle is in a continuous high-speed operation state. The vehicle runs at a stable speed for a long time, and high-frequency insulation testing is not required. Using a low-power detection mode reduces the detection frequency and reduces the computing burden on the MCU.

[0081] If the battery load is detected to be low (cruising, low and constant speed driving), the detection frequency is reduced.

[0082] Low SOC mode means that the vehicle's SOC (State of Charge) is less than 10%. The vehicle enters energy-saving mode, reducing MCU computing tasks to avoid affecting battery life.

[0083] Low-power detection mode only executes detection when the battery management system triggers a request or detects a change in vehicle status. The detection frequency of low-power detection mode can be once every 30 minutes for long-distance driving and once every hour for high-speed driving.

[0084] In one embodiment, the controller is connected to a battery management system.

[0085] Here, the controller is connected to the battery management system to obtain battery status data and decide whether to adjust the insulation detection mode.

[0086] The controller establishes a connection with the battery management system through the CAN bus or other communication protocols, and monitors the battery health status sent by the battery management system.

[0087] Read the insulation status data monitored by the battery management system to determine whether there is any abnormality.

[0088] Obtain abnormal events recorded by the battery management system, such as short-term leakage, abnormal temperature, abnormal current, etc.

[0089] Acquires battery management system monitoring data related to insulation status, including high-voltage system leakage monitoring, battery voltage, current, temperature, remaining capacity, insulation monitoring history data, and diagnostic fault codes.

[0090] When the operating status data indicates a long-distance driving mode, a low-load mode, or a low SOC mode, the steps of determining whether the vehicle enters a low-power consumption detection mode include: If abnormal detection information is received from the battery management system, the vehicle is adjusted to enter the complete insulation detection mode.

[0091] If the battery management system detects an abnormality, the system immediately exits low-power detection mode and enters full insulation detection mode. This abnormality can include at least one of: insulation impedance degradation (insulation impedance value drops below a safety threshold), battery short-term leakage detection (transient leakage), temperature anomaly (battery or high-voltage wiring harness temperature exceeds a safe range), or charge and discharge anomaly (overcharge, overdischarge, or abnormal current fluctuation).

[0092] Alternatively, if the current operating status data is different from the previous operating status data, the vehicle is adjusted to enter a complete insulation detection mode.

[0093] Here, if the vehicle operating status data changes, the low power consumption mode is exited and the full detection mode is entered to ensure real-time update of the insulation status.

[0094] Obtain current operating status data, including vehicle speed, acceleration, battery load, charging status, etc., and compare the current status data with the data at the previous moment.

[0095] Specifically, if the vehicle speed suddenly increases from 80km / h to 120km / h and enters high-speed mode, it needs to be adjusted to full detection mode.

[0096] If there are drastic changes in acceleration (such as emergency braking or rapid acceleration), the insulation condition will be affected and a complete inspection is required.

[0097] If the battery load increases dramatically (e.g. entering high power output mode), a complete insulation test is required.

[0098] If the running status data changes significantly, exit the low power detection mode: Furthermore, when the operating status data is a fast charging state, it is determined that the vehicle enters a complete insulation detection mode.

[0099] A complete insulation test is performed before fast charging to ensure there are no insulation hazards before high-voltage fast charging, avoiding potential leakage risks caused by high-voltage charging. This test is performed every 10 seconds to ensure stable insulation during charging. If insulation degradation is detected, the charging power is reduced and the user is notified to check the vehicle status.

[0100] Step S102 : 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.

[0101] In one embodiment, the insulation resistance includes a positive electrode insulation resistance and a negative electrode insulation resistance.

[0102] Step S102 includes: When the bridge measurement circuit reaches an initial equilibrium state, the ratio of the positive electrode insulation resistance value of the positive electrode insulation resistance to the negative electrode insulation resistance value of the negative electrode insulation resistance is calculated as a 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.

[0103] Here, the positive insulation resistance It is the insulation resistance of the high-voltage battery positive electrode to the ground, which mainly affects the leakage of the high-voltage positive electrode line.

[0104] Negative electrode insulation resistance It is the insulation resistance of the high-voltage battery negative electrode to the ground, which affects the insulation state of the high-voltage negative electrode circuit.

[0105] In the initial equilibrium state, the balance relationship of the bridge is shown in the following formula (1): (1) in, is the bridge reference resistance (fixed value), is the first resistance value, is the first insulation resistance ratio.

[0106] Step S103 : Based on the secondary balance state of the bridge measurement circuit, a second resistance value of the standard adjustable resistor is obtained, and a second insulation resistance ratio is calculated.

[0107] In one embodiment, the insulation resistance includes a positive electrode insulation resistance and a negative electrode insulation resistance; and the second insulation resistance ratio includes a positive electrode insulation resistance ratio and a negative electrode insulation resistance ratio.

[0108] When the bridge measurement circuit is in the positive electrode insulation detection mode, step S103 includes the following steps S401-S402: Step S401 : When the bridge measurement circuit reaches a secondary equilibrium state, the positive electrode insulation resistance value and the positive electrode parallel equivalent resistance value of the first voltage-dividing resistor in the bridge measurement circuit are calculated.

[0109] Here, the positive parallel equivalent resistance value is shown in the following formula (2): (2) in, is the positive parallel equivalent resistance value, is the first voltage-dividing resistor.

[0110] Step S402 , calculating the ratio of the positive electrode parallel equivalent resistance value to the negative electrode insulation resistance value as the positive electrode insulation resistance ratio; wherein the positive electrode insulation resistance ratio is equal to the ratio of the bridge reference resistance value to the second resistance value.

[0111] Here, the positive insulation resistance ratio is: , where the corresponding relationship between the positive electrode insulation resistance ratio, the bridge reference resistance value and the second resistance value is shown in the following formula (3): (3) in, is the second resistance value.

[0112] In one embodiment, when the bridge measurement circuit is in the negative electrode insulation detection mode, step S103 includes the following steps S501-S502: Step S501 : When the bridge measurement circuit reaches a secondary equilibrium state, the insulation resistance value of the negative electrode and the parallel equivalent resistance value of the negative electrode of the second voltage-dividing resistor in the bridge measurement circuit are calculated.

[0113] Here, the negative electrode parallel equivalent resistance value is shown in the following formula (4): (4) in, is the negative electrode parallel equivalent resistance value, is the second voltage divider resistor.

[0114] 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.

[0115] Here, the negative electrode insulation resistance ratio is: , where the corresponding relationship between the negative electrode insulation resistance ratio, the bridge reference resistance value and the second resistance value is shown in the following formula (5): (5) 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.

[0116] 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): (6) Substituting this into formula (7) we can get the following formula: (7) When the bridge measurement circuit is in the positive insulation detection mode, formula (1) and formula (5) are combined and substituted into formula (6), and the following formula (8) can be obtained: (8) Step S105 , determining whether the insulation resistance value meets a preset safety threshold, and if not, generating an alarm message.

[0117] Here, the preset safety threshold is set according to the actual situation and can be set to × Operating voltage.

[0118] when or When both are greater than the preset safety threshold, the insulation status is normal.

[0119] when or If any value exceeds a preset safety threshold, an insulation fault alarm is triggered. The controller sends a warning signal to the battery management system and stores the fault information. Simultaneously, an audible and visual alarm module is triggered, notifying 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.

[0120] The present invention provides an insulation detection method for a controller of an 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; the method includes: when a vehicle complete insulation detection mode start signal is detected, controlling the bridge measurement circuit to perform two balance calibrations and obtain measurement data; based on the 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 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 insulation resistor by combining the first insulation resistance ratio and the second insulation resistance ratio; determining whether the insulation resistance value meets a preset safety threshold, and generating an alarm message if it does not meet the threshold. 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 and negative insulation resistances can be calculated, and whether the preset safety threshold is met can be determined, thereby improving the accuracy of insulation detection and ensuring the safety of the high-voltage system of the electric vehicle. By adaptively selecting full, fast, or low-power detection modes depending on the vehicle's operating conditions, computing resource usage and system power consumption can be reduced, thereby balancing detection efficiency and endurance, and optimizing vehicle energy management. A zero-adjustment amplifier circuit amplifies the bridge measurement signal's gain and adjusts its zero-point deviation, improving the accuracy of insulation resistance calculations and enhancing the system's anti-interference capabilities. This allows for stable insulation status detection even under complex operating conditions, enhancing the safety and reliability of the battery management system.

[0121] Example 2: Figure 2 Schematic diagram of the insulation detection system provided in an embodiment of the present application.

[0122] 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.

[0123] The controller 2 is configured 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; The controller 2 is also used to obtain the standard adjustable resistance in the bridge measurement circuit 13 based on the initial equilibrium 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; 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 the preset safety threshold, and if not, generate an alarm message.

[0124] In one embodiment, referring to Figure 3 The high-voltage battery module 11 includes a high-voltage battery RT; 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 .

[0125] Here, the negative pole of the high-voltage battery RT is grounded GND, which is used to provide a high-voltage power supply to simulate the high-voltage system of an electric vehicle and serve as the power input end of the insulation detection to measure the insulation condition of the high-voltage battery to the ground.

[0126] The first voltage divider resistor The first end is connected to the positive electrode of the high voltage battery RT, and the second end is connected to the positive switch .

[0127] The second voltage divider resistor The first end is connected to the positive switch , and the second end is connected to the negative electrode of the high-voltage battery RT.

[0128] Bridge reference resistor The first end is connected to the positive terminal of the high voltage battery RT, and the second end is connected to the standard adjustable resistor The first end of the standard adjustable resistor The second end is connected to the negative electrode of the high-voltage battery RT.

[0129] Positive switch The second terminal of the switch is connected to the negative terminal of The first ends of the two terminals are connected to form a bridge structure.

[0130] Bridge reference resistor With standard adjustable resistor The connection point between them is the first midpoint X.

[0131] Positive switch With negative switch The connection point therebetween is a second midpoint O, which is grounded.

[0132] Here, the second midpoint O is used to measure the potential difference between the two sides of the bridge. The voltage at this point is , which is monitored by controller 2 to determine whether the bridge has reached a balanced state and adjust the standard adjustable resistance .

[0133] Positive switch With negative switch The switching of the bridge measurement circuit 13 is controlled separately.

[0134] The voltage relationship between the first midpoint X and the second midpoint O can be expressed as: ,in, is the first midpoint voltage, is the second midpoint voltage, is the voltage output signal. When the bridge is in a balanced state, , which means , indicating that the insulation state is normal. That is, when When , it indicates that the insulation status is normal. , it indicates an insulation fault. In one embodiment, referring to Figure 3 The insulation detection system further includes a zero adjustment amplifier circuit 14; the zero adjustment amplifier circuit 14 includes a first operational amplifier , the second operational amplifier , the third operational amplifier, the first resistor , the second resistor , the third resistor and the fourth resistor .

[0135] First operational amplifier The positive input terminal of the second operational amplifier is connected to the first midpoint; The positive input terminal is connected to the second midpoint.

[0136] First resistor The first terminal of the first operational amplifier The output terminal is connected to the first resistor The second end and the second resistor The first terminals of the third operational amplifier are connected to The positive input terminal is connected to the second resistor The second terminal of the third operational amplifier The output ends are connected to the controller.

[0137] The third resistor The first terminal and the second operational amplifier The output terminal is connected to the third resistor The second end and the fourth resistor The first terminals of the third operational amplifier are connected to The negative input terminal is connected to the fourth resistor The second end is connected to the controller.

[0138] Among them, the fifth resistor Connect Between the output terminal and the negative input terminal, a negative feedback is formed, and it is also connected to , the amplified signal is transmitted to . For stability output to prevent signal overload or distortion. The gain size is adjusted to adjust the amplification factor of the measurement signal and improve the accuracy of insulation resistance calculation.

[0139] Sixth resistor Connect The negative input terminal and A differential input path is formed between the negative input terminals of and Acquire symmetrical signals. Used to and The input voltage is divided and matched to enable it to correctly process the bridge measurement signal. This enhances the common-mode rejection ratio, improves noise immunity, and reduces the impact of electromagnetic interference on the measurement signal.

[0140] Seventh resistor Connect Between the output and negative input, a negative feedback is formed, and it is also connected to , the amplified signal is transmitted to . For control Gain, ensuring that its output signal is consistent with Form good symmetry and improve measurement accuracy. A negative feedback loop is formed to prevent signal drift and improve the stability of the amplifier circuit.

[0141] Here, the zero adjustment 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.

[0142] Operational amplifier 、 、 and resistors 、 、 、 A zero adjustment amplifier circuit is formed, and a resistor is added between the positive and negative busbars of the high voltage battery RT. and , forming another set of bridge arms, so that the positive insulation resistance and negative insulation resistance and and The four bridge arms together constitute the DC bridge. The zero-adjustment amplifier circuit 14 detects the midpoints O and X of the bridge arms. The unbalanced voltage between point O and point X is amplified by the zero-adjustment amplifier circuit 14 to make the voltage measurement more accurate.

[0143] The zero adjustment amplifier circuit 14 is Output voltage output signal and reference voltage signal To controller 2. Among them, The final detection result of the bridge measurement circuit 13 is transmitted to the controller 2 for insulation status analysis. If the insulation resistance value is lower than the safety threshold, the controller 2 will trigger an alarm mechanism. Depend on and The voltage divider network provided as The reference input is used to compare and detect whether the signal exceeds the safety range. and If the deviation exceeds the normal range, it indicates that the insulation condition is abnormal.

[0144] In one embodiment, referring to Figure 3 , insulation resistance includes positive insulation resistance and negative insulation resistance ; Positive electrode insulation resistance Connected to the positive electrode of the high-voltage battery RT; negative electrode insulation resistance Connected to the negative terminal of the high-voltage battery RT.

[0145] Positive electrode insulation resistance and negative insulation resistance The midpoint of the connecting wire is grounded.

[0146] Here, the positive insulation resistance Connect the positive electrode of the high-voltage battery RT and the first voltage divider resistor .

[0147] Negative electrode insulation resistance Connect the negative electrode of the high-voltage battery RT to the second voltage divider resistor .

[0148] In one embodiment, referring to Figure 4 The insulation detection system also includes an audible and visual alarm module 3 ; the audible and visual alarm module 3 is connected to the controller 2 .

[0149] An embodiment of the present application provides an insulation detection system. In this method, by adopting a two-time balance calibration method of a bridge measurement circuit and combining it with the signal processing capability of a zero-adjustment amplifier circuit, the positive electrode insulation resistance and the negative electrode insulation resistance can be accurately measured, thereby improving the accuracy and stability of insulation detection, thereby ensuring the safety of the high-voltage battery system, and dynamically adjusting the detection mode under different operating conditions (such as high-speed driving, fast charging, low load, etc.) to optimize the energy consumption management of the entire vehicle.

[0150] The computer program product provided in the embodiments of the present application includes a computer-readable storage medium storing program code. The instructions included in the program code can be used to execute the methods described in the previous method embodiments. For specific implementation, please refer to the method embodiments and will not be repeated here.

[0151] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described systems and devices can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0152] In addition, in the description of the embodiments of this application, unless otherwise specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0153] If the 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 the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a number of instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, and other media that can store program code.

[0154] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of this application and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0155] Finally, it should be noted that the above-described embodiments are only specific implementation methods of the present application, which are used to illustrate the technical solutions of the present application, rather than to limit them. The scope of protection of the present application is not limited thereto. Although the present application has been described in detail with reference to the above-described embodiments, those skilled in the art should understand that any person skilled in the art can modify or easily conceive of changes to the technical solutions described in the above-described embodiments within the technical scope disclosed in the present application, or perform equivalent replacements for some of the technical features thereof. Such modifications, changes, or replacements do not deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application shall be based on the scope of protection 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 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, obtaining a first resistance value of a standard adjustable resistor in the bridge measurement circuit, and calculating a first insulation resistance ratio; 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; By combining the first insulation resistance ratio and the second insulation resistance ratio, calculating the insulation resistance value corresponding to each insulation resistance; Determine whether the insulation resistance value meets a preset safety threshold, and if not, generate an alarm message.

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 insulation resistance includes positive electrode insulation resistance and negative electrode insulation resistance; 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: The insulation resistance includes a positive electrode insulation resistance and a negative electrode insulation resistance; 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, 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: 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 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; wherein 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: When the bridge measurement circuit reaches the secondary equilibrium state, calculating the insulation resistance value of the negative electrode 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; wherein 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 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; 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; and determine whether the insulation resistance value meets a preset safety threshold, and if not, generate an alarm message.

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 positive 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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