New energy vehicle high voltage circuit insulation resistance fault treatment method

Abstract

The present invention discloses a method for handling insulation resistance faults in a high-voltage circuit of a new energy vehicle, which mainly includes continuously detecting and feeding back the insulation resistance value of the high-voltage circuit of the whole vehicle after the whole vehicle is powered on; when the insulation resistance value is less than the first resistance threshold, only reporting early warning information; when the insulation resistance value is not greater than the second resistance threshold, reporting a first-level alarm message and synchronously outputting maintenance prompt information; when the insulation resistance value is not greater than the third resistance threshold, reporting a second-level alarm message, triggering the power-limited operation of the whole vehicle, and outputting power-limited and maintenance dual prompt information. The present invention refines the insulation resistance fault strategy of the whole vehicle to accurately identify the insulation resistance of the high-voltage components of the whole vehicle in advance, and avoids the situation where the insulation resistance value of the whole vehicle is seriously lower than the safety value when the high-voltage components fail, resulting in unexpected failure states or higher maintenance costs.

Description

Technical Field

[0001] The present invention relates to the field of automotive electronic and electrical technology, and in particular to a method for processing insulation resistance faults in a high-voltage circuit of a new energy vehicle. Background Art

[0002] At present, the voltage platform of electric vehicles is generally above 400V, and is developing towards a higher voltage of 800V. The voltage of high-voltage components and related working circuits has far exceeded the 60V limit voltage that the human body can withstand. Real-time monitoring and diagnosis of the insulation status of the entire vehicle and making treatments based on the vehicle's operating status are important means to ensure human safety.

[0003] Insulation resistance is the most basic insulation indicator for electrical equipment and electrical circuits. For new energy electric vehicles, the DC insulation resistance standard requirement for the vehicle is ≥100Ω / V at the maximum operating voltage, and the AC circuit is ≥500Ω / V. Based on this requirement, after the vehicle is powered on, relevant detection circuits and fault strategies are usually set. When the insulation resistance of the vehicle is lower than the set value, an audible and visual reminder is emitted to prompt the driver to confirm and repair in time.

[0004] To elaborate, the insulation resistance of the existing vehicle high-voltage circuit is tested by BMS for circuit insulation. Specifically, a larger detection resistor is connected in parallel to the positive insulation resistance (RP) and the negative insulation resistance (RN). When the insulation resistance on one side becomes low, the voltage on that side will be quickly lowered, so that the fault and resistance value can be detected. At the same time, a switch and a resistor are added to each side. By alternately switching the switches on both sides to change the equivalent resistance of the two poles to the ground, an unbalanced detection voltage is obtained on the positive and negative detection resistors, so as to calculate the insulation resistance of the positive and negative poles. The voltage on the positive and negative detection resistors changes with the switching cycle. When the insulation resistance of one pole becomes low, the voltage of the detection resistor on that side becomes smaller, and the voltage of the corresponding detection resistor on the other side becomes larger.

[0005] There is an existing vehicle insulation resistance fault strategy that when the vehicle insulation resistance is ≤0.2MΩ, the background reports an insulation warning and the vehicle can drive and operate normally; when the vehicle insulation resistance is ≤0.04MΩ, the instrument displays "EV is limited", then the power is limited and the insulation fault is reported remotely.

[0006] The disadvantages of this strategy are:

[0007] 1) The detection time is long, and the parallel resistance detection will reduce the insulation resistance between the vehicle body and the high-voltage components of the battery pack;

[0008] 2) During the driving process, the power may be interrupted or the vehicle may be unable to reach high voltage, requiring towing or on-site repair, increasing after-sales costs.

[0009] 3) The processing is not detailed enough and early warning cannot be given. When the insulation resistance value of the vehicle’s high-voltage circuit is very low, a warning is issued and power is limited.

[0010] There is another diagnostic strategy: when the vehicle is in the whole vehicle insulation fault detection condition, judge the operating state; if the vehicle is in the upper high voltage state, detect whether the vehicle is in the charging state; when it is detected that the vehicle is in the non-charging state, read the whole vehicle insulation resistance value and make corresponding fault prompts; when the whole vehicle insulation resistance value is less than 400KΩ, it can be determined that the vehicle has a whole vehicle insulation fault; when the whole vehicle insulation resistance is greater than 1200KΩ, it can be determined that the vehicle has not had a whole vehicle insulation fault.

[0011] The disadvantages of this strategy are:

[0012] 1) The strategy is not detailed enough, the insulation fault classification is too simple, and early warning is not possible;

[0013] 2) After the vehicle insulation fault detection is completed, it may be determined that the vehicle insulation fault has occurred, or it may not have occurred. The user is very likely to cause a safety accident when handling the fault and using the vehicle. Summary of the invention

[0014] In view of the above, the present invention aims to provide a method for handling insulation resistance faults in a high-voltage circuit of a new energy vehicle to solve the above-mentioned technical problems.

[0015] The technical solution adopted by the present invention is as follows:

[0016] The present invention provides a method for processing insulation resistance fault of a high-voltage circuit of a new energy vehicle, which comprises:

[0017] After the vehicle is powered on, the insulation resistance value of the high-voltage circuit of the vehicle is continuously detected and fed back;

[0018] When the insulation resistance value is detected to be less than the first resistance threshold, only insulation warning information is reported through remote communication;

[0019] When the insulation resistance value is detected to be ≤ the second resistance threshold, the insulation level 1 alarm information is reported through remote communication, and the instrument is simultaneously triggered to output maintenance prompt information;

[0020] When it is detected that the insulation resistance value is ≤ the third resistance threshold, the insulation secondary alarm information is reported through remote communication, the vehicle power limiting operation is triggered, and the instrument output power limiting mode and maintenance prompt information are synchronously triggered.

[0021] In at least one possible implementation, while only the insulation warning information is reported via remote communication, the instrument is triggered to output a high-voltage component replacement prompt message.

[0022] In at least one possible implementation manner, when it is detected that the insulation resistance value is ≥ the first resistance threshold, the detection data is continuously fed back and recorded only through remote communication.

[0023] In at least one possible implementation method, the processing method also includes: when the insulation resistance value is detected to be ≤ the second resistance threshold, if the whole vehicle is detected to be in a high-voltage power-on state, only the instrument outputs a prompt message; if the whole vehicle is detected to be in a charging state or in the power-on process, the high-voltage power supply of the whole vehicle is disabled.

[0024] In at least one possible implementation, the processing method further includes: when it is detected that the insulation resistance value is ≤ a third resistance threshold, if it is detected that the entire vehicle is in a charging state or in the power-on process, disabling high voltage power on the entire vehicle.

[0025] In at least one possible implementation method, the processing method also includes: in the process of continuously detecting the insulation resistance value, if the insulation resistance value is greater than the third resistance threshold, returning the relationship between the detected insulation resistance value and the second resistance threshold; if the insulation resistance value is greater than the second resistance threshold, returning the relationship between the detected insulation resistance value and the first resistance threshold.

[0026] Compared with the prior art, the main design concept of the present invention is that after the vehicle is powered on, the insulation resistance value of the high-voltage circuit of the vehicle is continuously detected and fed back; when the insulation resistance value is less than the first resistance threshold, only the warning information is reported; when the insulation resistance value is not greater than the second resistance threshold, the first-level alarm information is reported and the maintenance prompt information is output synchronously; when the insulation resistance value is not greater than the third resistance threshold, the second-level alarm information is reported, the power limiting operation of the vehicle is triggered, and the power limiting and maintenance dual prompt information is output. The present invention refines the insulation resistance fault strategy of the vehicle to accurately identify the insulation resistance of the high-voltage components of the vehicle in advance, and avoids the insulation resistance value of the vehicle being seriously lower than the safety value when the high-voltage components fail, resulting in unexpected failure states or higher maintenance costs. It is applicable to all new energy electric vehicles with high-voltage systems, including pure electric, hybrid and extended-range electric vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be further described below with reference to the accompanying drawings, in which:

[0028] Figure 1 A schematic diagram of a method for handling insulation resistance faults in a high-voltage circuit of a new energy vehicle provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0029] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be interpreted as limiting the present invention.

[0030] The present invention proposes an embodiment of a method for handling insulation resistance faults in a high-voltage circuit of a new energy vehicle. Specifically, Figure 1 shown, including:

[0031] Step S1: After the vehicle is powered on, continuously detect and feed back the insulation resistance value of the high-voltage circuit of the vehicle;

[0032] Specifically, after the vehicle is powered on, the battery management system BMS continuously detects the insulation resistance value of the high-voltage circuit and feeds it back to the vehicle controller VCU. The vehicle high-voltage circuit may include: battery pack, compressor, air conditioner PTC, PCU, charger and other high-voltage components, which are all connected in parallel to the main circuit of the battery pack through a high-voltage wiring harness.

[0033] Step S2: When the insulation resistance value is detected to be less than the first resistance threshold (such as 0.8MΩ), only the insulation warning information is reported through remote communication, and the instrument does not need to output this warning information. This can be expanded. For example, when the high-voltage component is flooded due to poor sealing, it may trigger the reporting of the insulation warning, but at this time the insulation resistance value has not dropped to the first level or higher level alarm requirements below, so the instrument can output the high-voltage component replacement prompt information; understandably, if the insulation resistance value is detected to be ≥0.8MΩ, the test results are only continuously fed back through remote communication and recorded in the background, and the instrument does not need any relevant display.

[0034] Step S3, when it is detected that the insulation resistance value is ≤ the second resistance threshold (the second resistance threshold is less than the first resistance threshold, such as 0.2MΩ), the insulation level 1 alarm information is reported through remote communication, and the instrument is synchronously triggered to output maintenance prompt information; it can also be added here that under the current working conditions, if it is detected that the whole vehicle is in a high-voltage power-on state, only the instrument outputs a prompt information on the vehicle side, and no other power limiting measures are performed; if it is detected that it is in a charging state or in the power-on process, the high voltage power on the whole vehicle is disabled.

[0035] Step S4: When the insulation resistance value is detected to be ≤ the third resistance threshold (the third resistance threshold is less than the second resistance threshold, such as 0.04MΩ), the insulation level 2 alarm information (the alarm level is set, and level 2 can be understood as serious) is reported through remote communication, triggering the vehicle power limit operation and synchronously triggering the instrument output power limit mode and maintenance prompt information. Combined with the previous example, under the current working condition, if the detection is in the charging state or the power-on process, the high voltage of the vehicle is disabled.

[0036] Finally, it can be added that in the above-mentioned process of continuously detecting the insulation resistance value, if the insulation resistance value is greater than the third resistance threshold, the relationship between the detected insulation resistance value and the second resistance threshold is returned; if the insulation resistance value is greater than the second resistance threshold, the relationship between the detected insulation resistance value and the first resistance threshold is returned.

[0037] In summary, the main design concept of the present invention is that after the vehicle is powered on, the insulation resistance value of the high-voltage circuit of the vehicle is continuously detected and fed back; when the insulation resistance value is less than the first resistance threshold, only the warning information is reported; when the insulation resistance value is not greater than the second resistance threshold, the first-level alarm information is reported and the maintenance prompt information is output synchronously; when the insulation resistance value is not greater than the third resistance threshold, the second-level alarm information is reported, the power limiting operation of the vehicle is triggered, and the power limiting and maintenance dual prompt information is output. The present invention refines the insulation resistance fault strategy of the vehicle to accurately identify the insulation resistance of the high-voltage components of the vehicle in advance, and avoid the insulation resistance value of the vehicle being seriously lower than the safety value when the high-voltage components fail, resulting in unexpected failure states or higher maintenance costs.

[0038] If the expressions expressing orientation are mentioned in the embodiments of the present invention, they are relative concepts based on the embodiments. In addition, "at least one" means one or more, and "plurality" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent the existence of A alone, the existence of A and B at the same time, and the existence of B alone. Among them, A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b and c can be represented by: a, b, c, a and b, a and c, b and c, or a and b and c, wherein a, b, c can be single or multiple.

[0039] The above describes in detail the structure, features and effects of the present invention based on the embodiments shown in the drawings, but the above is only a preferred embodiment of the present invention. It should be noted that the technical features involved in the above embodiments and their preferred methods can be reasonably combined and matched into a variety of equivalent schemes by those skilled in the art without departing from or changing the design ideas and technical effects of the present invention; therefore, the present invention is not limited to the scope of implementation shown in the drawings, and all changes made in accordance with the concept of the present invention, or modifications to equivalent embodiments with equivalent changes, which still do not exceed the spirit covered by the specification and drawings, should be within the protection scope of the present invention.

Claims

1. A method for handling insulation resistance faults in a high-voltage circuit of a new energy vehicle, characterized in that: include: After the vehicle is powered on, the insulation resistance value of the high-voltage circuit of the vehicle is continuously detected and fed back; When the insulation resistance value is detected to be less than the first resistance threshold, only insulation warning information is reported through remote communication; When the insulation resistance value is detected to be ≤ the second resistance threshold, the insulation level 1 alarm information is reported through remote communication, and the instrument is simultaneously triggered to output maintenance prompt information; When it is detected that the insulation resistance value is ≤ the third resistance threshold, the insulation secondary alarm information is reported through remote communication, the vehicle power limiting operation is triggered, and the instrument output power limiting mode and maintenance prompt information are synchronously triggered.

2. The method for handling insulation resistance fault of a high-voltage circuit of a new energy vehicle according to claim 1 is characterized in that: While only the insulation warning information is reported via remote communication, the instrument is triggered to output a high-voltage component replacement prompt.

3. The method for handling insulation resistance fault of a high-voltage circuit of a new energy vehicle according to claim 1 is characterized in that: When the insulation resistance value is detected to be ≥ the first resistance threshold, the detection data is continuously fed back and recorded only through remote communication.

4. The method for handling insulation resistance fault of a high-voltage circuit of a new energy vehicle according to claim 1 is characterized in that: The processing method also includes: when it is detected that the insulation resistance value is ≤ the second resistance threshold, if it is detected that the whole vehicle is in a high-voltage power-on state, only the instrument outputs a prompt message; if it is detected that the whole vehicle is in a charging state or in the power-on process, the high-voltage power supply of the whole vehicle is disabled.

5. The method for handling insulation resistance fault of a high-voltage circuit of a new energy vehicle according to claim 1 is characterized in that: The processing method further includes: when it is detected that the insulation resistance value is ≤ the third resistance threshold, if it is detected that the whole vehicle is in a charging state or in the power-on process, disabling high voltage power on the whole vehicle.

6. The method for handling insulation resistance fault of a high-voltage circuit of a new energy vehicle according to any one of claims 1 to 5, characterized in that: The processing method also includes: in the process of continuously detecting the insulation resistance value, if the insulation resistance value is greater than the third resistance threshold, returning to detect the relationship between the insulation resistance value and the second resistance threshold; if the insulation resistance value is greater than the second resistance threshold, returning to detect the relationship between the insulation resistance value and the first resistance threshold.

Images