A high-voltage wire harness humidity-responsive resistance mutation suppression system and method

Abstract

The present application relates to the technical field of new energy vehicle high-voltage electrical system, and particularly relates to a high-voltage wire harness humidity response type resistance mutation suppression system and method, comprising a data acquisition unit, multiplexing the existing sensors of the vehicle, real-time acquisition of high-voltage end voltage Ut, motor phase current effective value It, environmental humidity Henv and environmental temperature Tenv; a logic decision unit connected with the data acquisition unit, comprising a resistance calculation module and a double-factor determination module, an execution unit connected with the logic decision unit, comprising a PTC heating sheet embedded in the high-voltage connector terminal cavity and a heating control module, for differentiating heating and dehumidification of the connector terminal area according to the heating instruction, solving the problems of poor cost and adaptability, passive response lag and single intervention strategy at the present stage.

Description

Technical Field

[0001] This invention relates to the field of high-voltage electrical system technology for new energy vehicles, specifically to a humidity-responsive resistance mutation suppression system and method for high-voltage wiring harnesses. Background Technology

[0002] As the core carrier of power transmission, the high-voltage wiring harness of existing new energy vehicles directly affects the safety of the entire vehicle. Under harsh conditions such as humidity, heat, and high salt spray, the failure of the high-voltage connector seal can easily lead to moisture intrusion, causing condensation on the terminal surface, a decrease in insulation resistance, and ultimately insulation breakdown or high-voltage leakage.

[0003] Existing technologies are mainly divided into two categories: passive sealing protection and active monitoring and early warning. However, existing technologies have the following drawbacks: First, passive response is lagging. Physical sealing can only delay the intrusion of moisture and cannot cope with irreversible penetration after the sealing ring ages or breaks. Humidity sensors can only warn of external environmental risks and cannot detect local condensation and resistance degradation in the terminal area inside the wiring harness. Second, the intervention strategy is singular. Traditional solutions directly cut off the high-voltage circuit after insulation failure, which is a passive "one-size-fits-all" approach that can easily lead to unexpected vehicle downtime and lacks the ability to actively repair and prevent degradation in the early stages of a fault. Third, the cost and adaptability are poor. Adding a humidity sensor increases hardware costs and assembly complexity, making it difficult to adapt to existing wiring harness assemblies in current vehicle models at low cost.

[0004] At present, this invention proposes a humidity-responsive resistance mutation suppression system and method for high-voltage wiring harnesses to solve the problems mentioned in the background art. Summary of the Invention

[0005] The purpose of this invention is to provide a humidity-responsive resistance mutation suppression system and method for high-voltage wiring harnesses. This system and method aim to proactively block the moisture diffusion chain before insulation failure, accurately distinguish fault levels and intervene in a graded manner using a two-factor triggering model, and reuse existing sensor data of the vehicle to ensure compatibility with existing high-voltage wiring harness assemblies.

[0006] A humidity-responsive resistance mutation suppression system and method for high-voltage wiring harnesses includes a data acquisition unit that reuses existing sensors in the vehicle to collect high-voltage terminal voltage Ut, effective value of motor phase current It, ambient humidity Henv, and ambient temperature Tenv in real time.

[0007] The logic decision unit, connected to the data acquisition unit, includes a resistance calculation module and a two-factor judgment module. The resistance calculation module is used to calculate the real-time equivalent insulation resistance Rt based on Ut and It, and to calculate the resistance change ΔR and the rate of change VR. The two-factor judgment module is configured with a resistance change rate-humidity two-factor linkage model, which is used to make graded judgments based on ΔR, VR, Henv and Tenv, and output heating commands.

[0008] The execution unit, connected to the logic decision unit, includes a PTC heating element and a heating control module embedded in the high-voltage connector terminal cavity, used to perform differentiated heating and dehumidification of the connector terminal area according to the heating command.

[0009] Furthermore, the data acquisition unit reuses the BMS built-in voltage sampling circuit to acquire Ut, reuses the motor controller built-in Hall current sensor to acquire It, and reuses the vehicle temperature and humidity module to acquire Henv and Tenv, achieving a zero-addition sensor architecture.

[0010] Further specified, the resistance calculation module uses a calculation cycle of 60 seconds to calculate the real-time equivalent insulation resistance based on Ohm's law Rt = Ut / It, and calculates ΔR = Rt-Rt-60 and VR = ΔR / 60s; when the vehicle is idling or stopped and It < 10A, the resistance calculation module determines it as invalid data and suspends the ΔR calculation.

[0011] Further specified, the judgment priority of the dual-factor judgment module is set as: the resistance change rate is higher than the ambient humidity; the dual-factor judgment module includes: an emergency dehumidification judgment submodule, which triggers emergency dehumidification mode A when any of the following conditions are met: ΔR ≥ 0.03Ω; VR ≥ 0.0083Ω / s; ΔR continuously increases for 2 consecutive cycles and the cumulative ΔR ≥ 0.025Ω;

[0012] The preventive dehumidification judgment submodule triggers preventive dehumidification mode B when emergency dehumidification mode A is not triggered and the following conditions are met simultaneously: 0.01Ω≤ΔR<0.03Ω, Henv≥80%RH, and Tenv≤30℃.

[0013] Further specifying, the heating control module of the execution unit includes a mode A control submodule, used to output a 12V rated voltage and a 100% PWM duty cycle to control the PTC heating element to continuously heat for 60 seconds, so that the temperature of the connector terminal area rises to 60±2℃; and a mode B control submodule, used to output a 9V voltage and a 75% PWM duty cycle to control the PTC heating element to continuously heat for 30 seconds, so that the temperature of the connector terminal area rises to 50±2℃.

[0014] Furthermore, the execution unit also includes a safety constraint submodule, which is used to monitor the BMS voltage Ut in real time during heating, and immediately terminate heating when Ut < 500V.

[0015] Furthermore, the execution unit also includes a frequency limiting submodule, which limits the same connector to only one activation of Mode B heating within 30 minutes.

[0016] Furthermore, the execution unit also includes a fault recording submodule, which is used to count the number of times mode A is triggered within 1 hour. When the number is ≥2 times, a level 2 fault code is sent to the vehicle controller via the CAN bus.

[0017] Further, it also includes a fault-tolerant submodule for adjusting the heating strategy according to the vehicle's operating conditions: when the vehicle speed is greater than 30 km / h, the heating time of mode A is shortened to 40 seconds and mode B triggering is paused; when Tenv is less than -10℃, the target temperature of mode A is lowered to 55℃.

[0018] A method for a humidity-responsive resistance mutation suppression system for high-voltage wiring harnesses, characterized by the following specific steps: Step S1: Reuse the existing sensors of the vehicle to collect in real time the high-voltage terminal voltage Ut, the effective value of the motor phase current It, the ambient humidity Henv, and the ambient temperature Tenv;

[0019] Step S2: Calculate the real-time equivalent insulation resistance Rt based on Rt = Ut / It, with a period of 60 seconds, and calculate the resistance change ΔR and the rate of change VR.

[0020] Step S3, Step 3: Based on the resistance change rate-humidity dual-factor linkage model, a graded judgment is made, where the resistance change rate has higher priority than the ambient humidity: when ΔR≥0.03Ω or VR≥0.0083Ω / s, emergency dehumidification mode A is triggered; when 0.01Ω≤ΔR<0.03Ω and Henv≥80% RH and Tenv≤30℃, preventive dehumidification mode B is triggered.

[0021] Step S4: Perform differentiated heating based on the judgment result: In Mode A, heat continuously for 60 seconds at 100% duty cycle to 60±2℃; in Mode B, heat continuously for 30 seconds at 75% duty cycle to 50±2℃ to perform localized directional dehumidification on the high-voltage connector terminal area.

[0022] The advantages of this invention compared to the prior art are as follows:

[0023] 1. Actively interrupt the failure chain: By locally heating and evaporating condensation on the terminal surface, the degradation of insulation resistance is suppressed from the source, and the fault handling is moved from "power off after failure" to "intervention before degradation".

[0024] 2. Smarter tiered intervention: The dual-factor model accurately distinguishes between emergency dehumidification and preventive dehumidification, avoiding unnecessary heating and balancing safety and the lifespan of seals.

[0025] 3. Low cost and high adaptability: Reuse existing sensors, keep the cost of a single hardware set below $20, do not require modification of the main structure of the wiring harness, and are directly compatible with existing vehicle models.

[0026] 4. Fault-tolerant design for different operating conditions: The heating strategy is optimized for different operating conditions such as driving, charging, and low temperature to ensure power output and system safety. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall architecture of the high-voltage harness humidity-responsive resistance mutation suppression system of the present invention;

[0028] Figure 2 This is a flowchart of the two-factor determination logic and execution steps of the present invention.

[0029] The labels in the diagram correspond to: 1-High-voltage battery; 2-BMS controller; 3-VCU vehicle controller; 4-Motor controller; 5-High-voltage wiring harness assembly; 6-Connector (including PTC heating element); 7-Resistance calculation module; 8-Heating control module; 9-CAN 2.0B bus. Detailed Implementation

[0030] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0031] Example:

[0032] like Figure 1 and Figure 2 As shown, a high-voltage wiring harness humidity-responsive resistance mutation suppression system comprises a data acquisition unit, a logic decision unit, and an execution unit. Each unit is connected to a 12V low-voltage power supply network via the vehicle's CAN 2.0B bus. No new sensors are added. It reuses data from the vehicle's existing BMS, VCU, and external temperature and humidity modules, adapts to a 600V DC high-voltage platform, and is directly compatible with existing vehicle wiring harness assemblies.

[0033] The data acquisition unit performs high-voltage power circuit and voltage acquisition, from high-voltage battery 1 (nominal 600V DC) - high-voltage cable - BMS controller 2 high-voltage input terminal - high-voltage wiring harness assembly 5 - motor controller 4 - drive motor; BMS controller 2 has a built-in high-precision voltage sampling circuit (sampling accuracy ±0.1V), which acquires the high-voltage battery terminal voltage Ut in real time at a sampling frequency of 10Hz, and sends it to the resistance calculation module 7 at a rate of 1Hz via CAN 2.0B bus; Motor controller 4 has a built-in three-phase Hall current sensor (sampling accuracy ±0.5A), which acquires the effective value It of the motor phase current in real time, and after VCU3 filtering and noise reduction processing, sends it to the resistance calculation module 7 at a rate of 1Hz via CAN 2.0B bus; The vehicle's external temperature and humidity sensor (existing configuration, accuracy ±3% RH, ±1℃) acquires the ambient humidity Henv and ambient temperature T_env, and transmits them to the logic decision unit in real time via CAN bus, with an update cycle of 10 seconds / time.

[0034] The execution unit is connected to the logic decision unit and includes a PTC heating element embedded in the high-voltage connector terminal cavity and a heating control module. It is used to perform differentiated heating and dehumidification of the connector terminal area according to the heating command. The PTC heating element (rated power 15W, 12V drive, embedded in the high-voltage connector 6 terminal cavity, attached to the root of the terminal) is connected to a 2V low-voltage power supply through the heating control module 8. The heating control module 8 outputs a PWM signal (drive frequency 1kHz, duty cycle 0-100% adjustable) to precisely control the output power of the heating element and realize closed-loop temperature regulation.

[0035] The logic decision unit, connected to the data acquisition unit, includes a resistance calculation module and a two-factor decision module. The resistance calculation module 7 performs the following steps with a calculation cycle of 60 seconds:

[0036] 1. Cache the current cycle voltage Ut and current It, and calculate the real-time equivalent insulation resistance: Rt = Ut / It;

[0037] 2. Retrieve the previous cycle's buffer resistor value Rt-60 and calculate the resistance change: ΔR = Rt - Rt-60;

[0038] 3. Calculate the rate of change of resistance: VR = ΔR / 60s (unit: Ω / s).

[0039] 4. The trend record shows the change trend (rising / falling / stable) of ΔR over three consecutive periods.

[0040] 5. Remove outliers: If It < 10A (vehicle idling / stopping state), it is considered invalid data, and ΔR calculation is paused to avoid false triggering.

[0041] The decision logic and execution steps of the two-factor decision module are as follows:

[0042] The system defaults to standby monitoring mode (power consumption < 0.5W), and executes a complete judgment process every 60 seconds. Priority: resistance change rate > ambient humidity. The steps are as follows:

[0043] Step 1, Basic Data Reading and Preprocessing:

[0044] Read resistance calculation module 7 outputs: ΔR, VR, Rt, Rt-60; Read environmental data: Henv (real-time ambient humidity), Tenv (real-time ambient temperature); Read vehicle status: driving mode (parking / driving / charging) sent by VCU3, high voltage circuit on / off status;

[0045] Step 2, Grading criteria:

[0046] First priority—Emergency dehumidification trigger (Mode A): Mode A in step three is activated if any one of the following conditions is met: ΔR ≥ 0.03Ω; VR ≥ 0.0083Ω / s (i.e., 0.5Ω / h, laboratory failure threshold); ΔR continues to rise for two consecutive cycles, and the cumulative ΔR ≥ 0.025Ω;

[0047] Second priority—Preventing dehumidification triggering (Mode B): If Mode A is not triggered and the following two conditions are met simultaneously, then activate Mode B in step three: 0.01Ω ≤ ΔR < 0.03Ω; Henv ≥ 80% RH and Tenv ≤ 30℃ (high condensation conditions).

[0048] Third priority - Maintain standby: If the trigger conditions for modes A and B are not met, the system returns to standby mode;

[0049] Step 3, Heating Execution and Closed-Loop Control:

[0050] Mode A (Emergency Dehumidification): Outputs 12V rated voltage, PWM duty cycle 100%, continuous heating for 60 seconds; Temperature target: Rapidly heats up to 60±2℃ in the 6-terminal area of ​​the connector; Safety constraints: Real-time monitoring of BMS voltage during heating; If Ut < 500V (battery undervoltage), heating will be terminated immediately.

[0051] Mode B (Preventive Dehumidification): Outputs 9V voltage, PWM duty cycle 75%, continuous heating for 30 seconds; Temperature target: Connector 6-terminal area heats up to 50±2℃; Frequency limit: Mode B is only allowed to be activated once within 30 minutes for the same connector to avoid frequent heating and accelerated aging of seals;

[0052] Step 4, Heating Termination and Reset:

[0053] After the set heating time is reached, the heating control module 8 cuts off the output, and the PTC heating element cools down naturally. After 10 seconds of cooling, the system automatically resets to the standby monitoring state and restarts resistance calculation and data acquisition. Fault record: If mode A is triggered ≥ 2 times within 1 hour, a level 2 fault code is sent to VCU3 via CAN 2.0B bus 9, indicating abnormal wiring harness sealing and reminding for maintenance.

[0054] It also includes a fault-tolerant submodule for adjusting the heating strategy according to the vehicle's operating conditions: when the vehicle speed is >30km / h, power output is prioritized and the heating time of Mode A is shortened to 40 seconds; during charging: Modes A and B are allowed to be triggered normally; during charging, humidity fluctuates greatly and dehumidification protection is strengthened; during low temperature conditions (Tenv < -10℃): the target temperature of Mode A is lowered to 55℃ to avoid the connector from cracking due to thermal expansion and contraction caused by excessive temperature difference.

[0055] A method for a humidity-responsive resistance mutation suppression system for high-voltage wiring harnesses, comprising the following specific steps:

[0056] Step S1: Reuse the existing sensors of the vehicle to collect the high voltage terminal voltage Ut, the effective value of the motor phase current It, the ambient humidity Henv, and the ambient temperature Tenv in real time;

[0057] Step S2: Calculate the real-time equivalent insulation resistance Rt based on Rt = Ut / It, with a period of 60 seconds, and calculate the resistance change ΔR and the rate of change VR.

[0058] Step S3: Based on the resistance change rate-humidity dual-factor linkage model, a graded judgment is made, in which the resistance change rate has higher priority than the ambient humidity: when ΔR≥0.03Ω or VR≥0.0083Ω / s, emergency dehumidification mode A is triggered; when 0.01Ω≤ΔR<0.03Ω and Henv≥80% RH and Tenv≤30℃, preventive dehumidification mode B is triggered.

[0059] Step S4: Perform differentiated heating based on the judgment result: In Mode A, heat continuously for 60 seconds at 100% duty cycle to 60±2℃; in Mode B, heat continuously for 30 seconds at 75% duty cycle to 50±2℃ to perform localized directional dehumidification on the high-voltage connector terminal area.

[0060] The above provides a detailed description of a humidity-responsive resistance mutation suppression system and method for high-voltage wiring harnesses provided by the present invention. The specific embodiments are only used to help understand the method and core ideas of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A humidity-responsive resistance mutation suppression system for high-voltage wiring harnesses, characterized in that: This includes a data acquisition unit that reuses existing sensors in the vehicle to collect data in real time, including high-voltage terminal voltage Ut, effective value of motor phase current It, ambient humidity Henv, and ambient temperature Tenv. The logic decision unit, connected to the data acquisition unit, includes a resistance calculation module and a two-factor judgment module. The resistance calculation module is used to calculate the real-time equivalent insulation resistance Rt based on Ut and It, and to calculate the resistance change ΔR and the rate of change VR. The two-factor judgment module is configured with a resistance change rate-humidity two-factor linkage model, which is used to make graded judgments based on ΔR, VR, Henv and Tenv, and output heating commands. The execution unit, connected to the logic decision unit, includes a PTC heating element and a heating control module embedded in the high-voltage connector terminal cavity, used to perform differentiated heating and dehumidification of the connector terminal area according to the heating command.

2. The high-voltage wiring harness humidity-responsive resistance change suppression system according to claim 1, characterized in that: The data acquisition unit reuses the built-in voltage sampling circuit of the BMS to acquire the Ut, reuses the built-in Hall current sensor of the motor controller to acquire the It, and reuses the vehicle temperature and humidity module to acquire the Henv and Tenv, thus achieving a zero-addition sensor architecture.

3. The high-voltage wiring harness humidity-responsive resistance mutation suppression system according to claim 1, characterized in that: The resistance calculation module calculates the real-time equivalent insulation resistance based on Ohm's law Rt = Ut / It with a calculation cycle of 60 seconds, and calculates ΔR = Rt-Rt-60 and VR = ΔR / 60s. When the vehicle is idling or stopped and It < 10A, the resistance calculation module determines the data as invalid and suspends the ΔR calculation.

4. The high-voltage wiring harness humidity-responsive resistance mutation suppression system according to claim 1, characterized in that: The decision priority of the two-factor decision module is set as follows: the resistance change rate is higher than the ambient humidity. The dual-factor determination module includes an emergency dehumidification determination submodule, which triggers emergency dehumidification mode A when any of the following conditions are met: ΔR ≥ 0.03Ω; VR ≥ 0.0083Ω / s; ΔR continuously increases for two consecutive cycles and the cumulative ΔR ≥ 0.025Ω; The preventive dehumidification judgment submodule triggers preventive dehumidification mode B when emergency dehumidification mode A is not triggered and the following conditions are met simultaneously: 0.01Ω≤ΔR<0.03Ω, Henv≥80%RH, and Tenv≤30℃.

5. A humidity-responsive resistance mutation suppression system for high-voltage wiring harnesses according to claim 1, characterized in that... The heating control module of the execution unit includes a mode A control submodule, which outputs a 12V rated voltage and a 100% PWM duty cycle to control the PTC heating element to heat continuously for 60 seconds, raising the temperature of the connector terminal area to 60±2℃; and a mode B control submodule, which outputs a 9V voltage and a 75% PWM duty cycle to control the PTC heating element to heat continuously for 30 seconds, raising the temperature of the connector terminal area to 50±2℃.

6. The high-voltage wiring harness humidity-responsive resistance change suppression system according to claim 1, characterized in that: The execution unit also includes a safety constraint submodule, which is used to monitor the BMS voltage Ut in real time during heating and immediately terminate heating when Ut < 500V.

7. A high-voltage wiring harness humidity-responsive resistance mutation suppression system according to claim 5, characterized in that: The execution unit also includes a frequency limiting submodule, which limits the same connector to only one activation of Mode B heating within 30 minutes.

8. A high-voltage wiring harness humidity-responsive resistance mutation suppression system according to claim 4, characterized in that: The execution unit also includes a fault recording submodule, which is used to count the number of times mode A is triggered within 1 hour. When the number is ≥2 times, a level 2 fault code is sent to the vehicle controller via the CAN bus.

9. A high-voltage wiring harness humidity-responsive resistance mutation suppression system according to claim 1, characterized in that: It also includes a fault-tolerant submodule for adjusting the heating strategy according to the vehicle's operating conditions: when the vehicle speed is greater than 30 km / h, the heating time of mode A is shortened to 40 seconds and mode B triggering is paused; when Tenv is less than -10℃, the target temperature of mode A is lowered to 55℃.

10. A method for a humidity-responsive resistance mutation suppression system for high-voltage wiring harnesses according to any one of claims 1-9, characterized in that: The specific steps are as follows: Step S1: Reuse the existing sensors of the vehicle to collect the high voltage terminal voltage Ut, the effective value of the motor phase current It, the ambient humidity Henv, and the ambient temperature Tenv in real time; Step S2: Calculate the real-time equivalent insulation resistance Rt based on Rt = Ut / It with a period of 60 seconds, and calculate the resistance change ΔR and the rate of change VR. , Step S3: Based on the resistance change rate-humidity dual-factor linkage model, a graded judgment is made, in which the resistance change rate has higher priority than the ambient humidity: when ΔR≥0.03Ω or VR≥0.0083Ω / s, emergency dehumidification mode A is triggered; when 0.01Ω≤ΔR<0.03Ω and Henv≥80% RH and Tenv≤30℃, preventive dehumidification mode B is triggered. Step S4: Perform differentiated heating based on the judgment result: In Mode A, heat continuously for 60 seconds at 100% duty cycle to 60±2℃; in Mode B, heat continuously for 30 seconds at 75% duty cycle to 50±2℃ to perform localized directional dehumidification on the high-voltage connector terminal area.

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