Multi-safety protection device and method for high-voltage system of electric vehicle

Abstract

The invention discloses a multi-safety protection device and method for a high-voltage system of an electric vehicle, and belongs to the technical field of high-voltage safety of the electric vehicle, and the method comprises the following steps: S1, after the vehicle is powered on, completing self-inspection, parameter calibration and protection logic loading of each module, and after the vehicle is confirmed to be normal, enabling the high-voltage system to enter a standby activation state; s2, synchronously acquiring data of different dimensions through two channels, performing environment compensation, judging insulation and electric leakage states of the system, and triggering early warning or fault protection; s3, monitoring the current of each loop in real time, triggering a fusing action based on a fault condition, and independently triggering ultimate fusing protection through a hard wire when the main controller fails; s4, accurately positioning concurrent and superimposed faults of each branch, isolating fault modules in a grading manner, reserving core load power supply and supporting remote emergency disposal and degradation protection; and S5, carrying out fault recovery and system reset. Differential protection actions can be triggered according to different fault types and severity degrees, and the use safety of the electric automobile is improved.

Description

Technical Field

[0001] This invention relates to the field of high-voltage safety technology for electric vehicles, and in particular to a multi-safety protection device and method for a high-voltage system in an electric vehicle. Background Technology

[0002] Currently, with the rapid development of the electric vehicle industry, the high-voltage system (300-1000Vdc), as the core power source of vehicles, is directly related to the safety of passengers and the property of the vehicle. Existing safety protection technologies for electric vehicle high-voltage systems mostly employ single protection mechanisms, such as only setting up insulation monitoring modules or single-stage fuses, which have the following technical defects: First, the protection response is delayed, making it unable to quickly identify and handle sudden faults such as short circuits and leakage. Secondly, the accuracy of fault location is low. After a fault occurs, the entire power is cut off, which affects the vehicle's emergency driving ability and makes it inconvenient for repair and troubleshooting. Third, it has poor adaptability. Affected by factors such as ambient temperature and humidity, the accuracy of insulation monitoring is easily reduced, leading to misjudgment or missed detection of faults. Fourth, the protection gradient of the fuse is insufficient. A single-stage fuse device will trigger a complete power outage when there is a slight overload, which will affect the availability of the system. In extreme cases, it may not respond in time and cause safety accidents.

[0003] Existing technologies for insulation monitoring mostly employ single-channel acquisition methods without temperature compensation, making them prone to monitoring errors in high and low temperature environments. Fuse protection typically uses a single fuse in the main circuit, failing to achieve partial disconnection in the event of a branch circuit fault, leading to the paralysis of the entire high-voltage system. Fault isolation relies solely on simple relay disconnection, which cannot accurately locate the faulty module, resulting in low maintenance efficiency. Therefore, there is an urgent need for a safety protection device and method for electric vehicle high-voltage systems that integrates multiple protection mechanisms, offers rapid response, accurate location, and high reliability, to address the shortcomings of existing technologies. Summary of the Invention

[0004] The purpose of this invention is to provide a multi-safety protection device and method for high-voltage systems in electric vehicles. By organically combining real-time monitoring of electrical isolation, multi-level gradient fuse protection, and intelligent and precise fault isolation, a closed-loop protection system covering the entire process of monitoring, early warning, fuse breaking, isolation, and recovery is achieved, thereby improving the safety, reliability, and fault handling flexibility of the high-voltage system.

[0005] To achieve the above objectives, the present invention provides a multi-safety protection device for a high-voltage system of an electric vehicle, comprising: High-voltage power supply module, including power battery pack and high-voltage distribution box; The electrical isolation monitoring module is electrically connected to the high-voltage power supply module and the two ends of the high-voltage load. It includes a main monitoring unit, a backup monitoring unit, a temperature compensation unit, a humidity compensation unit, an altitude compensation unit, and a fault switching unit. The main monitoring unit and the backup monitoring unit adopt a dual-channel redundant design. A multi-level fuse protection module is connected in series with the high-voltage distribution box, including branch circuit fuse unit, main circuit fuse unit, emergency fuse unit and hard-wire independent trigger unit; The intelligent fault isolation module includes a high-voltage relay array, a fault location unit, a status feedback unit, and a multi-fault collaborative processing unit. The main control module is connected to the electrical isolation monitoring module, the multi-level fuse protection module, and the intelligent fault isolation module. It adopts a dual MCU redundancy design and supports backup of CANFD and Ethernet dual communication links. The communication and early warning module is connected to the main control module and includes a graded audible and visual alarm unit, a vehicle-mounted display unit, a wireless communication unit, and a remote emergency response interface.

[0006] Preferably, the main monitoring unit and the backup monitoring unit of the electrical isolation monitoring module are used to collect the insulation resistance and leakage current of the high-voltage system in real time, and the insulation resistance monitoring thresholds meet the following requirements: static insulation resistance ≥100Ω / V, dynamic insulation resistance ≥50Ω / V, and maximum allowable leakage current ≤5mA; The temperature compensation unit uses formula R 25 =R Tw ×10 (a×(25-Tw)) Correction is performed, and humidity compensation is achieved using formula R. std =R h The correction is performed using ×(1-b×(h-60)% / 100), where R 25 R is the insulation resistance at a reference temperature of 25°C. Tw The measured value is at the actual temperature Tw, where a is the temperature coefficient of the insulation material, and R is the measured value. std R is the insulation resistance under standard humidity conditions. h The measured value is the actual humidity h, and b is the humidity influence coefficient; when the altitude is ≥2000m, the leakage current monitoring threshold is corrected by decreasing by 10% for every 1000m increase; the switching response time of the fault switching unit is ≤20ms, and the emergency monitoring accuracy is not less than 90% of the normal monitoring accuracy.

[0007] Preferably, the parameters of the multi-level fuse protection module are dynamically loaded and matched by the main control module: the rated current of the branch fuse unit is 1.2-1.5 times the rated operating current of the corresponding branch, and the fuse is triggered when the overload is 200%, with a response time of 50-100ms; the rated current of the main circuit fuse unit is 1.1-1.3 times the total rated current of the high-voltage system, and the fuse is triggered when the overload is 300%, with a response time of 20-50ms; the discrimination range of the emergency fuse unit is 20-100kA, and it is triggered when the short-circuit current is ≥5 times the rated current, with a response time ≤10ms; the hard-wire independent trigger unit adopts a voltage threshold triggering mechanism, and the emergency fuse is directly triggered when the short-circuit voltage drops by ≥30%, with a response time ≤5ms.

[0008] This invention also provides a protection method for a multi-safety protection device in a high-voltage system of an electric vehicle, comprising the following steps: S1. System initialization and pre-processing: After the vehicle is powered on, each module completes self-test, parameter calibration and protection logic loading. After confirming that everything is normal, the high-voltage system enters standby activation state. S2. Real-time monitoring of electrical isolation: By synchronously collecting data from different dimensions through dual channels and performing environmental compensation, the system insulation and leakage status is determined, triggering early warning or fault protection and identifying occasional faults. S3, Multi-level fuse protection: Real-time monitoring of current in each circuit, triggering fuse action based on fault level, current intensity and platform type, and independent triggering of ultimate fuse protection through hard-wired when the main controller fails. S4 Intelligent Fault Isolation: Accurately locates concurrent and superimposed faults in each branch, isolates faulty modules according to priority, retains power supply to core loads, and supports remote emergency handling and degradation protection; S5. Fault Recovery and System Reset: After maintenance, fault codes are cleared via diagnostic equipment or remotely. After passing the semi-automatic reset verification, the high-voltage lockout is released and normal power supply is restored.

[0009] Preferably, S2 specifically includes the following steps: S21. The main monitoring unit and the backup monitoring unit simultaneously collect the insulation resistance value and leakage current signal between the positive and negative terminals of the high-voltage power supply and the vehicle ground. The collection frequency is 10-20Hz. The ambient temperature, humidity and altitude data of the monitoring point are collected simultaneously. S22, temperature compensation unit, humidity compensation unit, and altitude compensation unit respectively perform multi-dimensional correction on the collected insulation resistance value and leakage current signal to eliminate the influence of environmental fluctuations and obtain the equivalent monitoring value under the reference conditions. S23. The main control module compares the calibrated monitoring values ​​with the preset thresholds and judges the electrical isolation status based on signal stability: if the insulation resistance is ≥ the dynamic threshold and the leakage current is ≤ 5mA, it is judged as a normal state and continuous monitoring is performed; if the insulation resistance is between the static threshold and the dynamic threshold or the leakage current is between 3-5mA, it is judged as a warning state; if the insulation resistance is < the static threshold or the leakage current is > 5mA, it is judged as a fault state; at the same time, it identifies intermittent faults and permanent faults by the signal duration; the judgment criteria for intermittent faults are that the duration is < 100ms and there is no repeated triggering. S24. When a warning state is determined, the communication warning module triggers a level one audible and visual warning, the graded audible and visual alarm unit emits a low-frequency buzzer and a yellow warning light, and the vehicle display unit issues an abnormality prompt; when a fault state is determined, the main control module immediately marks the fault level as a level one serious fault, triggering subsequent fuse and isolation protection; when an intermittent fault is identified, the fault information is recorded and only the vehicle display prompt is triggered, without triggering fuse and isolation; if both monitoring units fail simultaneously, the fault switching unit starts emergency monitoring to maintain basic protection capabilities.

[0010] Preferably, step S3 specifically includes the following steps: S31. The branch circuit fuse unit monitors the current of each high-voltage load branch in real time, the main circuit fuse unit monitors the total current of the high-voltage bus, the emergency fuse unit is in standby mode, the current acquisition frequency is 50Hz, and the main control module dynamically matches the fuse threshold corresponding to the current high-voltage platform. S32. When the current in a branch reaches 200% of its rated current or a short circuit occurs in the branch, the corresponding branch fuse unit will immediately trigger the fuse to cut off the power supply to the branch and send a branch fuse signal to the main control module. S33. If the main circuit current continues to rise to 300% of the total rated current after the branch circuit blows, or if the main circuit current exceeds the standard even though no branch circuit fault has occurred, the main circuit fuse unit will be triggered and blown, cutting off the main output of the high-voltage power supply. At this time, except for the emergency power supply branch, the entire high-voltage system will be de-energized. S34. In the event of an extreme short circuit fault or failure of the main circuit fuse, the emergency fuse unit will immediately trigger the fuse to achieve the ultimate power outage protection of the high-voltage system, and at the same time lock the high-voltage power output to prevent secondary power supply; if the main control module fails, the hard-wired independent trigger unit will directly trigger the emergency fuse after detecting the voltage abnormality. S35. After the fuse tripping action is completed, the multi-level fuse protection module reports the status of each fuse unit to the main control module. The main control module marks the fault level as a level two serious fault and simultaneously triggers a level two audible and visual warning. The graded audible and visual alarm unit emits a high-frequency buzzer and a red warning light.

[0011] Preferably, step S4 specifically includes the following steps: S41. The fault location unit receives multi-dimensional monitoring data from the electrical isolation monitoring module and fuse signals from the multi-level fuse protection module. Combining this with the real-time operating status data of each high-voltage load, it performs fault feature screening and type differentiation through a fault feature matching algorithm, and then locates the fault location based on the screened features through a fault location algorithm. S42. If it is a single branch fault, the intelligent fault isolation module controls the high-voltage relay of the corresponding branch to disconnect, realizing the physical isolation between the faulty branch and the main system, while other normal branches maintain power supply, and the vehicle maintains basic driving functions. S43. If the main circuit fails, the intelligent fault isolation module controls all high-voltage branch relays to disconnect, and at the same time disconnects the high-voltage power supply from the main circuit to achieve fault isolation of the entire system, while only retaining low-voltage emergency power supply. S44. If there are multiple branch concurrent faults or superimposed faults, the multi-fault collaborative processing unit will isolate the faulty branches in sequence according to the principle of prioritizing the severity and minimizing the impact range, while retaining the power supply to the core load. The priority ranking is calculated using an innovative priority algorithm formula. The main control module sends graded fault location information and emergency response prompts to the driver through the communication early warning module, and uploads the fault data to the remote monitoring platform to support remote emergency command reception. S45. After the isolation action is completed, the status feedback unit sends an isolation confirmation signal to the main control module. After the fault is isolated, the main control module continuously monitors the status of the isolated area. If it is an intermittent fault, it will automatically attempt to restore power supply after the safety conditions are met. If it is a permanent fault, it will maintain the isolation status until manual repair. If a protection module temporarily fails during operation, the main control module will start the degraded protection mode to maintain the core protection function.

[0012] Preferably, in S41, the fault feature matching algorithm employs a redundant data verification mechanism, combining fault codes, frozen frame data, real-time data streams, and environmental parameters to filter fault features and distinguish types; the fault location algorithm uses a multi-dimensional feature weighted confidence formula for calculation, specifically: ; in, C For fault location reliability, n The number of feature dimensions, For the first i Weight coefficients of dimensional features For the first i The actual detection value of the dimensional feature. For the first i The normal minimum value of the dimensional feature. For the first i Fault threshold of dimensional features For the first i The effectiveness coefficient of the dimensional feature; The intermittent fault identification adopts a signal stability judgment + repeated trigger verification mechanism, with a false judgment rate of ≤0.5%. The judgment algorithm formula is as follows: ; in, P The coefficient for determining occasional failures; T Duration of the fault signal; T 0 represents the intermittent fault time threshold; N The number of times the fault signal is repeatedly triggered; N 0 is the threshold for repeated triggering.

[0013] Preferably, in S44, the innovation priority algorithm formula is: ; in, For the first j Prioritization of handling faulty branches The larger the size, the higher the priority for handling it. For current overload weight, For the influence range weight, As a voltage sag weight, and satisfying , For the first j The actual fault current of each branch For the first j The rated current of each branch, For the first j The number of loads affected by a branch failure This represents the total load capacity of the high-voltage system. For the first j Voltage drop caused by a branch circuit fault. This is the rated voltage for the high-voltage system.

[0014] Preferably, in S5, after clearing the fault code, the main control module starts the semi-automatic reset process, re-executes step S1, automatically completes the insulation resistance retest, branch continuity verification, and fuse unit status detection. After confirming that each protection module is in normal condition, electrical isolation meets the standard, and fuse units are intact, the high-voltage system lock is released and normal power supply is restored. In maintenance mode, the main control module starts the temporary protection priority to prevent maintenance misoperation from triggering high-voltage power-on.

[0015] Therefore, the beneficial effects of the above-mentioned multi-safety protection device and method for electric vehicle high-voltage system are as follows: (1) The protection mechanism of the present invention is diversified and redundant and reliable, breaking through the limitations of traditional single protection. When the core module fails, it can still maintain the basic protection function and can fully cover various high voltage faults such as leakage, overload, short circuit, and multiple branch concurrent faults. (2) The present invention has a fast response speed and sufficient backup protection, which can quickly deal with sudden failures and extreme scenarios and prevent the accident from escalating; (3) The fault location of the present invention is accurate and flexible. It can accurately isolate the faulty branch and retain the power supply of the core load, improve the emergency driving capability of the vehicle, and effectively avoid accidental triggering of occasional faults.

[0016] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the composition structure of an embodiment of a multi-safety protection device for a high-voltage system of an electric vehicle according to the present invention; Figure 2 This is a schematic diagram of the execution flow of a protection method for a multi-safety protection device for a high-voltage system of an electric vehicle according to the present invention. Detailed Implementation

[0018] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0019] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0020] Example 1: like Figure 1 As shown, this embodiment provides a multi-safety protection device for a high-voltage system in an electric vehicle, including: The high-voltage power supply module is used to provide stable high-voltage power to the high-voltage load of electric vehicles, and includes a power battery pack and a high-voltage distribution box. The power battery pack has an output voltage range of 300-1000Vdc. In this embodiment, a ternary lithium battery pack is used, with an output voltage of 400Vdc (compatible with the 800Vdc platform) and a capacity of 80kWh.

[0021] The high-voltage distribution box integrates a high-voltage busbar, branch distribution unit, and expandable interface, supporting plug-and-play expansion of new high-voltage loads and compatible with multiple high-voltage platforms such as 400V / 800V. In this embodiment, the high-voltage distribution box integrates 6 basic high-voltage branches, corresponding to the drive motor, on-board charger (OBC), DC-DC converter, air conditioning compressor, PTC heater, and high-voltage auxiliary load, respectively, and reserves 2 expansion interfaces.

[0022] The electrical isolation monitoring module is electrically connected to the high-voltage power supply module and the high-voltage load. It is used to collect real-time insulation resistance, leakage current, and environmental parameters such as temperature, humidity, and altitude of the high-voltage system. It includes a main monitoring unit, a backup monitoring unit, a temperature compensation unit, a humidity compensation unit, an altitude compensation unit, and a fault switching unit. The main and backup monitoring units adopt a dual-channel redundant design, each containing an insulation resistance tester (accuracy 0.1MΩ), a leakage current sensor with a range of 0-10mA and an accuracy of ±0.1mA, and configured with a PT100 temperature sensor (measuring range -40℃~85℃), a humidity sensor (range 0-100%RH, accuracy ±3%RH), and an altitude sensor (range 0-5000m, accuracy ±10m). These sensors are used to collect real-time insulation resistance and leakage current of the high-voltage system, and the insulation resistance monitoring thresholds meet the following requirements: static insulation resistance ≥100Ω / V, dynamic insulation resistance ≥50Ω / V, and the maximum allowable leakage current ≤5mA.

[0023] The fault switching unit provides emergency monitoring backup in case of dual unit failure. Temperature compensation, humidity compensation, and altitude compensation units are used to eliminate interference from multiple environmental factors on monitoring accuracy. The temperature compensation unit uses formula R... 25 =R Tw ×10 (a×(25-Tw)) Correction is performed, and humidity compensation is achieved using formula R. std =R h The correction is performed using ×(1-b×(h-60)% / 100), where R 25 R is the insulation resistance at a reference temperature of 25°C. Tw The measured value is at the actual temperature Tw, where a is the temperature coefficient of the insulation material, and R is the measured value. std R is the insulation resistance under standard humidity conditions. h The measured value is the actual humidity h, and b is the humidity influence coefficient; when the altitude is ≥2000m, the leakage current monitoring threshold is corrected by decreasing by 10% for every 1000m increase; the switching response time of the fault switching unit is ≤20ms, and the emergency monitoring accuracy is not less than 90% of the normal monitoring accuracy.

[0024] The multi-stage fuse protection module, connected in series in the high-voltage distribution box, includes branch circuit fuse units, main circuit fuse units, emergency fuse units, and hard-wire independent triggering units. The parameters of the multi-stage fuse protection module are dynamically loaded and matched through the main control module: the rated current of the branch circuit fuse unit is 1.2-1.5 times the rated operating current of the corresponding branch, triggering fuse at 200% overload with a response time of 50-100ms; the rated current of the main circuit fuse unit is 1.1-1.3 times the total rated current of the high-voltage system, triggering fuse at 300% overload with a response time of 20-50ms; the emergency fuse unit has a discrimination range of 20-100kA, triggering when the short-circuit current is ≥5 times the rated current with a response time ≤10ms; the hard-wire independent triggering unit adopts a voltage threshold triggering mechanism, directly triggering emergency fuse when the short-circuit voltage drop is ≥30% with a response time ≤5ms.

[0025] In this embodiment, the branch circuit fuse unit uses Eaton Bussmann series fuses with rated currents of 150A for the drive motor branch, 30A for the OBC branch, 20A for the DC-DC branch, 25A for the air conditioning compressor branch, 35A for the PTC heater branch, and 10A for the high-voltage auxiliary load branch. The fuses are triggered when the overload reaches 200%, with a response time of 80ms. The main circuit fuse unit uses a 200A rated current fuse, which is triggered when the overload reaches 300%, with a response time of 30ms. The emergency fuse unit uses a 50kA breaking capacity fuse with a rated current of 250A, triggered when the short-circuit current is ≥1000A, with a response time of 5ms. The hard-wired independent trigger unit uses a voltage comparator design, triggered when the voltage drop is ≥30%, with a response time of 3ms.

[0026] The intelligent fault isolation module includes a high-voltage relay array, a fault location unit, a status feedback unit, and a multi-fault collaborative processing unit. The high-voltage relay array uses 12V control type high-voltage relays with contact withstand voltage ≥1000Vdc. The fault location unit integrates an MCU chip (STM32H743) and supports CAN FD bus communication. The status feedback unit outputs status signals through optocoupler isolation. The multi-fault collaborative processing unit can simultaneously identify three or more concurrent faults.

[0027] The main control module communicates with the electrical isolation monitoring module, the multi-level fuse protection module, and the intelligent fault isolation module. It adopts a dual STM32H743 MCU chip redundancy design with a main frequency of 480MHz. It supports dual communication link backup of CANFD and Ethernet and has a fault self-diagnosis function. When a module fails, it can automatically switch to a single MCU degraded operation mode.

[0028] The communication and early warning module, which communicates with the main control module, includes a tiered audible and visual alarm unit, an in-vehicle display unit, a wireless communication unit, and a remote emergency response interface. In this embodiment, the audible and visual alarm unit uses a buzzer (1kHz for the first-level warning and 2kHz for the second-level warning) and yellow / red warning lights. The in-vehicle display unit is integrated into the instrument panel. The wireless communication unit uses 4G+WiFi dual-mode communication, supporting remote data upload and emergency command reception.

[0029] like Figure 2 As shown, the protection method based on the above-mentioned multiple safety protection devices for the high-voltage system of electric vehicles includes the following steps: S1. System initialization and pre-processing: After the vehicle is powered on, each module completes self-test, parameter calibration and protection logic loading. After confirming that everything is normal, the high-voltage system enters standby activation state.

[0030] The main control module initiates a dual MCU synchronous self-test and self-tests for each protection module. The electrical isolation monitoring module calibrates the insulation resistance reference value (400Vdc corresponds to a static threshold of 40MΩ and a dynamic threshold of 20MΩ), temperature, humidity, and altitude compensation parameters. The multi-level fuse protection module resets the fuse state and loads the fuse threshold corresponding to the 400V platform. The intelligent fault isolation module closes all high-voltage branch relays. After the self-test passes, the high-voltage system enters a standby activation state. The main control module loads the protection logic and hierarchical priority mechanism, and completes the setting of the first / secondary warning threshold and the configuration of maintenance mode parameters.

[0031] S2. Real-time monitoring of electrical isolation: By synchronously collecting data from different dimensions through dual channels and performing environmental compensation, the system's insulation and leakage status is determined, triggering early warnings or fault protection and identifying intermittent faults. Specifically, this includes the following steps: S21. The main monitoring unit and the backup monitoring unit simultaneously collect the insulation resistance value and leakage current signal between the positive and negative terminals of the high-voltage power supply and the vehicle body ground. The collection frequency is 10-20Hz. The ambient temperature, humidity and altitude data of the monitoring point are collected simultaneously.

[0032] S22, temperature compensation unit, humidity compensation unit, and altitude compensation unit respectively perform multi-dimensional correction on the collected insulation resistance value and leakage current signal to eliminate the influence of environmental fluctuations and obtain equivalent monitoring values ​​under the reference conditions.

[0033] S23. The main control module compares the calibrated monitoring value with the preset threshold and judges the electrical isolation status based on signal stability: if the insulation resistance is ≥ the dynamic threshold and the leakage current is ≤ 5mA, it is judged as a normal state and continuous monitoring is performed; if the insulation resistance is between the static threshold and the dynamic threshold or the leakage current is between 3-5mA, it is judged as a warning state; if the insulation resistance is < the static threshold or the leakage current is > 5mA, it is judged as a fault state; at the same time, the intermittent fault and permanent fault are identified by the signal duration; the judgment criteria for intermittent fault is that the duration is < 100ms and there is no repeated triggering.

[0034] S24. When a warning state is determined, the communication warning module triggers a level one audible and visual warning, the graded audible and visual alarm unit emits a low-frequency buzzer and a yellow warning light, and the vehicle display unit issues an abnormality prompt; when a fault state is determined, the main control module immediately marks the fault level as a level one serious fault, triggering subsequent fuse and isolation protection; when an intermittent fault is identified, the fault information is recorded and only the vehicle display prompt is triggered, without triggering fuse and isolation; if both monitoring units fail simultaneously, the fault switching unit starts emergency monitoring to maintain basic protection capabilities.

[0035] In this embodiment, the main monitoring unit and the backup monitoring unit collect insulation resistance and leakage current data every 50ms, and simultaneously collect temperature (25℃), humidity (60%RH), and altitude (100m) data at the monitoring point; the multi-dimensional compensation unit does not require calibration (it is under reference conditions), and the main control module judges it to be in a normal state and continues to monitor; if the ambient temperature rises to 60℃ and the humidity is 85%RH, the collected insulation resistance value is 30MΩ and the leakage current is 3.8mA. After multi-dimensional calibration, the equivalent insulation resistance is 36.2MΩ and the leakage current is 3.2mA, which is judged to be a warning state and triggers a first-level audible and visual warning; if the insulation is damaged and the insulation resistance drops to 15MΩ and the leakage current rises to 6mA (lasting for 200ms), it is judged to be a permanent fault, marked as a first-level serious fault and triggers subsequent protection; if the leakage current rises instantaneously to 6.2mA (lasting for 80ms), it is identified as an intermittent fault, only recorded and prompted, without triggering fuse isolation.

[0036] S3. Multi-level fuse protection: Real-time monitoring of current in each circuit, triggering fuse action based on fault level, current intensity, and platform type. In the event of main controller failure, ultimate fuse protection is triggered independently via hard-wired connection. The specific steps include: S31, the branch circuit fuse unit monitors the current of each high-voltage load branch in real time, the main circuit fuse unit monitors the total current of the high-voltage bus, the emergency fuse unit is in standby mode, the current acquisition frequency is 50Hz, and the main control module dynamically matches the fuse threshold corresponding to the current high-voltage platform.

[0037] S32. When the current of a branch reaches 200% of its rated current (overload state) or a branch short circuit occurs (current suddenly increases to more than 3 times the rated current), the corresponding branch fuse unit will immediately trigger the fuse to cut off the power supply to the branch and send a branch fuse signal to the main control module.

[0038] S33. If the main circuit current continues to rise to 300% of the total rated current after the branch circuit blows, or if the main circuit current directly exceeds the standard without a branch circuit fault, the main circuit fuse unit will be triggered and blown, cutting off the main output of the high-voltage power supply. At this time, except for the emergency power supply branch, the entire high-voltage system will be de-energized.

[0039] S34. In the event of an extreme short-circuit fault (short-circuit current ≥ 5 times the total rated current) or the main circuit fuse fails, the emergency fuse unit will immediately trigger the fuse to achieve the ultimate power-off protection of the high-voltage system, and at the same time lock the high-voltage power output to prevent secondary power supply; if the main control module fails, the hard-wired independent trigger unit will directly trigger the emergency fuse after detecting the voltage abnormality.

[0040] S35. After the fuse tripping action is completed, the multi-level fuse protection module reports the status of each fuse unit to the main control module. The main control module marks the fault level as a level two serious fault and simultaneously triggers a level two audible and visual warning. The graded audible and visual alarm unit emits a high-frequency buzzer and a red warning light.

[0041] In this embodiment, it is assumed that the drive motor branch and the air conditioning compressor branch both experience short circuits simultaneously (multiple branch concurrent faults). The currents of the two branches suddenly change to 400A and 60A respectively, and the corresponding branch fuse units are triggered to blow (response time 78ms and 72ms), cutting off the power supply to the two branches. If the short circuit fault is not eliminated, the main circuit current rises to 650A, and the main circuit fuse unit is triggered to blow (response time 29ms), cutting off the total power supply to the high-voltage bus. If the main control module suddenly fails, the hard-wired independent trigger circuit detects a voltage drop of 35% and directly triggers the emergency fuse (response time 3.2ms), achieving the final power outage.

[0042] S4. Intelligent Fault Isolation: Accurately locates concurrent and superimposed faults in each branch, isolates faulty modules according to priority, retains power supply to the core load, and supports remote emergency handling and degradation protection. Specifically, it includes the following steps: S41. The fault location unit receives multi-dimensional monitoring data from the electrical isolation monitoring module and fuse signals from the multi-level fuse protection module. Combining this with the real-time operating status data of each high-voltage load, it uses a fault feature matching algorithm to filter fault features and distinguish types. Then, it uses a fault location algorithm to locate the fault location based on the filtered features.

[0043] The fault feature matching algorithm employs a redundant data verification mechanism, combining fault codes, frozen frame data, real-time data streams, and environmental parameters to filter fault features and distinguish their types. The fault location algorithm uses a multi-dimensional feature weighted confidence formula for calculation, specifically: in, C For fault location reliability, n The number of feature dimensions, For the first i Weight coefficients of dimensional features For the first i The actual detection value of the dimensional feature. For the first i The normal minimum value of the dimensional feature. For the first i Fault threshold of dimensional features For the first i The effectiveness coefficient of the dimensional feature.

[0044] The intermittent fault identification adopts a signal stability judgment + repeated trigger verification mechanism, with a false judgment rate of ≤0.5%. The judgment algorithm formula is as follows: in, P The coefficient for determining occasional failures; T Duration of the fault signal; T 0 represents the intermittent fault time threshold; N The number of times the fault signal is repeatedly triggered; N 0 is the threshold for repeated triggering.

[0045] S42. If it is a single branch fault, the intelligent fault isolation module controls the high-voltage relay of the corresponding branch to disconnect, realizing the physical isolation between the faulty branch and the main system, while other normal branches maintain power supply, and the vehicle maintains basic driving functions.

[0046] S43. If the main circuit fails, the intelligent fault isolation module controls all high-voltage branch relays to disconnect, and at the same time disconnects the high-voltage power supply from the main circuit, thereby achieving fault isolation of the entire system and retaining only low-voltage emergency power supply.

[0047] S44. If there are multiple branch concurrent faults or superimposed faults, the multi-fault collaborative processing unit will isolate the faulty branches in sequence according to the principle of prioritizing the severity and minimizing the impact range, while retaining the power supply to the core load. The priority ranking is calculated using an innovative priority algorithm formula. The main control module sends graded fault location information and emergency response prompts to the driver through the communication early warning module, and at the same time uploads the fault data to the remote monitoring platform, supporting remote emergency command reception.

[0048] The innovation priority algorithm formula is: in, For the first j Prioritization of handling faulty branches The larger the size, the higher the priority for handling it. For current overload weight, For the influence range weight, As a voltage sag weight, and satisfying , For the first j The actual fault current of each branch For the first j The rated current of each branch, For the first j The number of loads affected by a branch failure This represents the total load capacity of the high-voltage system. For the first j Voltage drop caused by a branch circuit fault. This is the rated voltage for the high-voltage system.

[0049] S45. After the isolation action is completed, the status feedback unit sends an isolation confirmation signal to the main control module. After the fault is isolated, the main control module continuously monitors the status of the isolated area. If it is an intermittent fault, it will automatically attempt to restore power supply after the safety conditions are met. If it is a permanent fault, it will maintain the isolation status until manual repair. If a protection module temporarily fails during operation, the main control module will start the degraded protection mode to maintain the core protection function.

[0050] In this embodiment, the fault location unit combines the fuse signals of the two branches, the short-circuit current characteristics, and the load operating status, and substitutes them into the fault location confidence formula to calculate the drive motor branch location confidence. C 1 = 0.98, location reliability of the air conditioner compressor branch C 2=0.97, both meet the precise positioning conditions, accurately identifying it as a dual-branch concurrent fault; the multi-fault collaborative processing unit substitutes the value into the priority formula for calculation, driving the motor branch. P 1 = 0.82 ( =0.4, =0.3, =0.3, =400A, =150A, =2, =6, =140V, =400V), air conditioner compressor branch P2=0.65, prioritize isolating the drive motor branch, then the air conditioning compressor branch, while retaining power supply to core branches such as OBC and DC-DC, and the vehicle switches to emergency driving mode; the main control module displays "Drive motor and air conditioning compressor branch fault, isolated, can drive at low speed to the repair station" on the instrument panel, and at the same time uploads the fault data to the remote monitoring platform, supporting remote reception of commands to forcibly disconnect all non-core branches; if the backup monitoring unit fails during driving, the fault switching unit immediately starts emergency monitoring to maintain insulation and leakage current monitoring functions.

[0051] S5. Fault Recovery and System Reset: After maintenance, fault codes are cleared via diagnostic equipment or remotely. After a semi-automatic reset verification, the high-voltage lockout is released, and normal power supply is restored. After clearing the fault codes, the main control module initiates the semi-automatic reset process, re-executing step S1 to automatically complete insulation resistance retesting, branch continuity verification, and fuse unit status detection. Once it confirms that all protection modules are functioning normally, electrical isolation meets standards, and fuse units are intact, the high-voltage system lockout is released, and normal power supply is restored. In maintenance mode, the main control module activates temporary protection priorities to prevent maintenance misoperations from triggering high-voltage power-on.

[0052] Therefore, the present invention adopts the above-mentioned multi-safety protection device and method for electric vehicle high-voltage system. Through layered and progressive protection logic, it realizes the organic integration of real-time monitoring of electrical isolation, multi-level gradient fuse protection and intelligent and precise fault isolation. It can trigger differentiated protection actions for different fault types and severity, with fast response speed and high protection reliability. It can effectively avoid safety accidents such as electric shock and fire caused by high voltage leakage, short circuit, and overload, and improve the safety of electric vehicle high-voltage system throughout its entire life cycle.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A multiple safety protection device for high-voltage system of electric vehicle, characterized in that, The application relates to a high-voltage power supply system, which comprises the following modules: a high-voltage power supply module comprising a power battery pack and a high-voltage distribution box; an electrical isolation monitoring module electrically connected to the high-voltage power supply module and the high-voltage load, comprising a main monitoring unit, a backup monitoring unit, a temperature compensation unit, a humidity compensation unit, an altitude compensation unit and a fault switching unit, wherein the main monitoring unit and the backup monitoring unit adopt a dual-channel redundant design; a multi-stage fuse protection module connected in series to the high-voltage distribution box, comprising a branch fuse unit, a main loop fuse unit, an emergency fuse unit and a hard-wire independent triggering unit; an intelligent fault isolation module comprising a high-voltage relay array, a fault positioning unit, a state feedback unit and a multi-fault cooperative processing unit; a main control module in communication connection with the electrical isolation monitoring module, the multi-stage fuse protection module and the intelligent fault isolation module, adopting a dual-MCU redundant design and supporting CANFD and Ethernet dual-communication link backup; a communication early warning module in communication connection with the main control module, comprising a hierarchical audible and visual alarm unit, a vehicle-mounted display unit, a wireless communication unit and a remote emergency disposal interface.

2. The multiple safety protection device for high-voltage system of electric vehicle according to claim 1, characterized in that: The main monitoring unit and the backup monitoring unit of the electrical isolation monitoring module are used for collecting the insulation resistance and the leakage current of the high-voltage system in real time, and the insulation resistance monitoring threshold satisfies: static insulation resistance >=100 ohm / V, dynamic insulation resistance >=50 ohm / V and the maximum allowable leakage current <=5 mA; The temperature compensation unit uses formula R 25 =R Tw ×10 (a×(25-Tw)) Correction is performed, and humidity compensation is achieved using formula R. std =R h The correction is performed using ×(1-b×(h-60)% / 100), where R 25 R is the insulation resistance at a reference temperature of 25°C. Tw The measured value is at the actual temperature Tw, where a is the temperature coefficient of the insulation material, and R is the measured value. std R is the insulation resistance under standard humidity conditions. h The measured value is the actual humidity h, and b is the humidity influence coefficient; when the altitude is ≥2000m, the leakage current monitoring threshold is corrected by decreasing by 10% for every 1000m increase; the switching response time of the fault switching unit is ≤20ms, and the emergency monitoring accuracy is not less than 90% of the normal monitoring accuracy.

3. The multiple safety protection device for high-voltage system of electric vehicle according to claim 1, characterized in that: The parameters of the multi-stage fuse protection module are dynamically loaded by the main control module to match the parameters: the rated current of the branch fuse unit is 1.2-1.5 times the rated working current of the corresponding branch, the branch fuse is triggered when the overload is 200%, and the response time is 50-100 ms; the rated current of the main loop fuse unit is 1.1-1.3 times the total rated current of the high-voltage system, the main loop fuse is triggered when the overload is 300%, and the response time is 20-50 ms; the discrimination range of the emergency fuse unit is 20-100 kA, the emergency fuse is triggered when the short-circuit current is >=5 times the rated current, and the response time is <=10 ms; the hard-wire independent triggering unit adopts a voltage threshold triggering mechanism, the emergency fuse is directly triggered when the short-circuit voltage drop is >=30%, and the response time is <=5 ms.

4. The protection method of a multiple safety protection device of a high-voltage system of an electric vehicle according to any one of claims 1 to 3, characterized in that, The application further relates to a high-voltage power supply system, and the system comprises the following steps: S1, system initialization and pre-preparation: after the vehicle is powered on, self-checking, parameter calibration and protection logic loading of each module are completed, and after confirmation of normality, the high-voltage system enters a standby activation state; S2, real-time electrical isolation monitoring: different dimension data are synchronously collected through dual channels, and environment compensation is carried out, the system insulation and leakage state are judged, early warning or fault protection is triggered, and occasional faults are identified; S3, multi-stage fuse protection: each loop current is monitored in real time, and the fuse action is triggered based on the fault grade, the current intensity and the platform type; when the main controller fails, the ultimate fuse protection is triggered through the hard-wire independent triggering unit; S4, intelligent fault isolation: each branch is accurately positioned, and the faults are isolated according to the priority, the core load power supply is reserved, and remote emergency disposal and degradation protection are supported; S5, fault recovery and system reset: after maintenance, the fault code is cleared through a diagnostic device or remotely, and after semi-automatic reset verification, the high-voltage locking is released to recover normal power supply.

5. The protection method of the multiple safety protection device of the high-voltage system of the electric vehicle according to claim 4, characterized in that: In S2, the following steps are further included: S21, the main monitoring unit and the standby monitoring unit collect the insulation resistance value between the positive and negative poles of the high-voltage power supply and the vehicle body ground and the leakage current signal at the same time, the collection frequency is 10-20 Hz, and the environment temperature, humidity and altitude data of the monitoring point are collected synchronously; S22, the temperature compensation unit, the humidity compensation unit and the altitude compensation unit respectively correct the collected insulation resistance value and leakage current signal in multiple dimensions to eliminate the influence of environmental fluctuations and obtain the equivalent monitoring value under the reference condition; S23, the main control module compares the corrected monitoring value with the preset threshold value, judges the electrical isolation state according to the signal stability: if the insulation resistance is greater than or equal to the dynamic threshold value and the leakage current is less than or equal to 5 mA, it is determined that the state is normal, and the monitoring is continued; if the insulation resistance is between the static threshold value and the dynamic threshold value or the leakage current is between 3 mA and 5 mA, it is determined that the state is a warning state; if the insulation resistance is less than the static threshold value or the leakage current is greater than 5 mA, it is determined that the state is a fault state; at the same time, the occurrence of the fault is identified according to the signal duration; the determination basis of the occasional fault is that the duration is less than 100 ms and there is no repeated triggering; S24, when it is determined that the state is a warning state, the communication warning module triggers a first sound and light warning, the hierarchical sound and light alarm unit emits a low-frequency beep and a yellow warning light, and the vehicle display unit emits an abnormal prompt; when it is determined that the state is a fault state, the main control module immediately marks the fault level as a first serious fault, triggers subsequent fusing and isolation protection; when it is identified as an occasional fault, the fault information is recorded and only the vehicle display prompt is triggered, without triggering fusing and isolation; if both monitoring units fail at the same time, the fault switching unit starts emergency monitoring to maintain basic protection capability.

6. The protection method of the multiple safety protection device of the high-voltage system of the electric vehicle according to claim 4, characterized in that: S3, specifically includes the following steps: S31, the branch fusing unit monitors the current of each high-voltage load branch in real time, the main circuit fusing unit monitors the total current of the high-voltage bus, and the emergency fusing unit is in standby state, the current collection frequency is 50 Hz, and the main control module dynamically matches the fusing threshold value corresponding to the current high-voltage platform; S32, when the current of a branch reaches 200% of its rated current or a branch short circuit occurs, the corresponding branch fusing unit immediately triggers fusing to cut off the power supply of the branch, and sends a branch fusing signal to the main control module; S33, if the branch fusing is followed by a continuous increase in the main circuit current to 300% of the total rated current, or the main circuit current directly exceeds the standard without branch fault, the main circuit fusing unit triggers fusing to cut off the main output of the high-voltage power supply, at this time, the entire high-voltage system is powered off except for the emergency power supply branch; S34, if an extreme short circuit fault occurs or the main circuit fusing fails, the emergency fusing unit immediately triggers fusing to realize ultimate power-off protection of the high-voltage system, and at the same time, the high-voltage power supply output is locked to prevent secondary power supply; if the main control module fails, the hard-wired independent triggering unit directly triggers the emergency fusing after detecting voltage abnormality; S35, after the fusing action is completed, the multi-level fusing protection module feeds back the state of each fusing unit to the main control module, the main control module marks the fault level as a second serious fault, synchronously triggers a second sound and light warning, and the hierarchical sound and light alarm unit emits a high-frequency beep and a red warning light.

7. The protection method of the multiple safety protection device of the high-voltage system of the electric vehicle according to claim 4, characterized in that: S4, specifically includes the following steps: S41, the fault positioning unit receives the multi-dimensional monitoring data of the electrical isolation monitoring module, the fuse signal of the multi-stage fuse protection module, combines the real-time working state data of each high-voltage load, performs fault feature screening and type differentiation through a fault feature matching algorithm, and then locates the fault position based on the screened features through a fault positioning algorithm; S42, if it is a single branch fault, the intelligent fault isolation module controls the high-voltage relay of the corresponding branch to be disconnected, realizes the physical isolation of the fault branch and the main system, the other normal branches remain powered, and the vehicle maintains the basic driving function; S43, if it is a main loop fault, the intelligent fault isolation module controls all high-voltage branch relays to be disconnected, simultaneously disconnects the connection between the high-voltage power supply and the main loop, realizes the fault isolation of the whole system, and only the low-voltage emergency power supply is reserved; S44, if it is a multi-branch concurrent fault or superimposed fault, the multi-fault cooperative processing unit isolates the fault branches in turn according to the principle of severity priority and minimum impact range, and reserves the core load power supply, and the priority order is calculated by using an innovative priority algorithm formula; the main control module sends hierarchical fault positioning information and emergency disposal prompts to the driver through the communication warning module, and uploads the fault data to the remote monitoring platform to support remote emergency command reception; S45, after the isolation action is completed, the state feedback unit sends an isolation confirmation signal to the main control module; after the fault is isolated, the main control module continuously monitors the state of the isolation area, if it is an occasional fault, it automatically attempts to restore power supply after meeting the safety conditions; if it is a permanent fault, the isolation state is maintained until manual repair; if a protection module temporarily fails during driving, the main control module starts the degraded protection mode to maintain the core protection function.

8. The protection method of the multiple safety protection device of the high-voltage system of the electric vehicle according to claim 7, characterized in that: In S41, the fault feature matching algorithm uses a redundancy data checking mechanism, combines fault codes, frozen frame data, real-time data streams, and environmental parameters to perform fault feature screening and type differentiation; the fault positioning algorithm uses a multi-dimensional feature weighted confidence formula calculation, specifically: ； in, C For fault location reliability, n The number of feature dimensions, For the first i Weight coefficients of dimensional features For the first i The actual detection value of the dimensional feature. For the first i The normal minimum value of the dimensional feature. For the first i Fault threshold of dimensional features For the first i The effectiveness coefficient of the dimensional feature; Occasional fault identification uses signal stability judgment + repeated trigger checking mechanism, the false rejection rate is ≤0.5%, and the judgment algorithm formula is: ； wherein, P is an occasional fault determination coefficient; T is a fault signal duration; T 0 is an occasional fault time threshold; N is a number of repeated fault signal triggers; N 0 is a repeated trigger threshold.

9. The protection method of a multiple safety protection device of a high-voltage system of an electric vehicle according to claim 4, characterized in that: In S44, the innovative priority algorithm formula is: ； in, For the first j Prioritization of handling faulty branches The larger the size, the higher the priority for handling it. For current overload weight, For the influence range weight, As a voltage sag weight, and satisfying , For the first j The actual fault current of each branch For the first j The rated current of each branch, For the first j The number of loads affected by a branch failure This represents the total load capacity of the high-voltage system. For the first j Voltage drop caused by a branch circuit fault. This is the rated voltage for the high-voltage system.

10. The protection method of the multiple safety protection device of the high-voltage system of the electric vehicle according to claim 4, characterized in that: In S5, after the fault code is cleared, the main control module starts a semi-automatic reset process, re-executes step S1, automatically completes insulation resistance re-measurement, branch on-off verification, and fuse unit state detection, confirms that each protection module is normal, the electrical isolation meets the standard, and the fuse unit is intact, then releases the high-voltage system lock, and restores normal power supply; in the maintenance mode, the main control module starts the temporary protection priority to prevent maintenance misoperation from triggering high-voltage power-on.

Images