Search

CN-122008875-A - High-voltage insulation or interlocking fault processing system and processing method for pure electric vehicle

CN122008875ACN 122008875 ACN122008875 ACN 122008875ACN-122008875-A

Abstract

The invention discloses a high-voltage insulation or interlocking fault processing system and a processing method of a pure electric vehicle, wherein the processing system is realized based on a VCU whole vehicle controller, an MCU electric drive control unit electrically connected with the VCU whole vehicle controller, a BMS battery management system and an IC instrument, and comprises a four-in-one assembly, wherein the four-in-one assembly is connected with a BMS power battery, a quick charge and a driving motor through a main interlocking loop, and the four-in-one assembly is connected with a high-voltage accessory system a through a secondary interlocking loop; and the high-voltage output end of the BMS power battery is respectively connected with the MCU motor controller, the high-voltage accessory system a and the quick charge through a first connecting circuit, a second connecting circuit and a third connecting circuit which are arranged in parallel, the second connecting circuit is provided with a high-voltage accessory relay, and the third connecting circuit is provided with a quick charge relay. The invention realizes the function degradation under the fault condition instead of the function loss, ensures the safety of the trolley, and simultaneously effectively reduces the maintenance cost and the vehicle using cost of the trolley owner.

Inventors

  • JIN LV
  • YANG LIU
  • WANG ZHEN
  • YANG YI
  • WANG LIANYI

Assignees

  • 贵州长江汽车有限公司

Dates

Publication Date
20260512
Application Date
20260401

Claims (9)

  1. 1. A high-voltage insulation or interlocking fault processing system of a pure electric vehicle is characterized by being based on a VCU whole vehicle controller, an MCU electric drive control unit electrically connected with the VCU whole vehicle controller, a BMS battery management system and an IC instrument, and comprises a four-in-one assembly, wherein the four-in-one assembly is connected with a BMS power battery, a quick charging and a driving motor through a main interlocking loop, the four-in-one assembly is connected with a high-voltage accessory system a through a secondary interlocking loop, and a high-voltage output end of the BMS power battery is connected with the MCU motor controller, the high-voltage accessory system a and the quick charging through a first connecting circuit, a second connecting circuit and a third connecting circuit which are arranged in parallel respectively, a high-voltage accessory relay is arranged on the second connecting circuit, and a quick charging relay is arranged on the third connecting circuit.
  2. 2. The electric only vehicle high voltage insulation or interlock fault handling system of claim 1 wherein the high voltage accessory system a includes an air pump, DCDC, PTC, WPTC and a compressor disposed in parallel on the second connection circuit.
  3. 3. A method for handling high voltage insulation or interlock faults in a blade electric vehicle based on the handling system of claim 1 or 2, comprising: Step S1, under a normal state, a high-voltage accessory relay on a second connection circuit corresponding to the high-voltage accessory system a is normally closed; step S2, when an insulation fault or an interlocking fault occurs, the following processing is performed: the high-voltage accessory relay is disconnected before the insulation fault is triggered, and if the insulation fault resistance value is recovered to be normal, an alarm prompt is carried out, so that emergency driving is not affected; when the secondary interlocking loop fails, the high-voltage accessory relay is disconnected firstly, and meanwhile, the alarm prompt is carried out, so that emergency driving is not affected.
  4. 4. The method for handling high voltage insulation or interlock faults of a pure electric vehicle according to claim 3, wherein in step S2, when the PDU judges that the insulation resistance and duration sent by the BMS are lower than the preset values, the high voltage accessory relay is disconnected before the insulation fault is triggered, and whether the insulation fault resistance is recovered to be normal is judged: if the insulation fault resistance value is recovered to be normal, alarming and prompting are carried out, so that emergency driving is not affected; if the insulation resistance value is not recovered after a certain time of disconnection, closing the high-voltage accessory relay corresponding to the high-voltage accessory system a; Meanwhile, the insulation resistance value is continuously lower than an alarm threshold value 30S, when the vehicle speed is 0 and the time of 30S is reached, the BMS controls the battery pack relay to be disconnected, an insulation fault CAN signal is sent, an insulation fault icon prompt is carried out after the instrument receives the signal, and any high voltage is forbidden after the VCU receives the trigger of the BMS insulation alarm fault.
  5. 5. The method for processing high-voltage insulation or interlocking faults of a pure electric vehicle according to claim 4 is characterized in that when the PDU judges that insulation resistance value sent by the BMS is continuously lower than 500 Ω/V and the duration time reaches 10S, the PDU is controlled to disconnect a high-voltage accessory relay on a second connection circuit corresponding to the high-voltage accessory system a, if the insulation resistance value is recovered after disconnection, the PDU sends a CAN signal AttLowInsulation =1 to inform an instrument, the instrument alarms of 'high-voltage accessory system insulation fault, please enter a station for maintenance', and if the insulation resistance value is not recovered after disconnection for 20S, the high-voltage accessory relay corresponding to the high-voltage accessory system a is closed.
  6. 6. The method for handling high voltage insulation or interlocking faults of a pure electric vehicle according to claim 5, wherein after a PDU is dormant and wakes up, a high voltage accessory relay corresponding to a high voltage accessory system a is controlled to be closed, attLowInsulation =0, and the pure electric vehicle can be normally used after maintenance is completed and a negative electrode is broken.
  7. 7. The method for handling high voltage insulation or interlock faults of a pure electric vehicle according to claim 3, wherein in the step S2, when a main/sub high voltage interlock occurs, fault signals pdu_ InterlockSts to VCU are reported, wherein the single sub interlock is sent out 1, the single main interlock is sent out 2, the main/sub interlock triggers out 3 at the same time, and the normal is sent out 0; And after judging that the high-voltage accessory relay is adhered, the PDU sends PDU_ FaultGrade =3 to the VCU to control the vehicle to pull down high voltage.
  8. 8. The method for processing high-voltage insulation or interlocking fault of a pure electric vehicle according to claim 7, wherein the method for judging the secondary high-voltage interlocking fault is that the VCU detects that the interlocking loop input is at a high level, then the VCU interlocking loop is normal (pdu_ InterlockSts |=1 and |=3, then vcu_ InterlockSts =0), otherwise the VCU interlocking loop is abnormal vcu_ InterlockSts =1, and the VCU detects any high-voltage interlocking fault, whether the primary interlocking or the secondary interlocking, when the vehicle speed is greater than 2KM/h, the fault maturation time is 30S, and when the vehicle speed is less than or equal to 2KM/h, the fault maturation time is 3S.
  9. 9. The method for handling high voltage insulation or interlock faults in a battery electric vehicle according to claim 8, wherein the specific handling steps of the primary/secondary interlock loop fault include: 1) The VCU detects secondary interlocking reported by the PDU, the signal PDU_ InterlockSts =1, the signal VCU_ InterlockSts =1 is sent after the fault is mature, the high-voltage accessory relay is disconnected after the PDU is received, and meanwhile, the instrument prompts 'secondary interlocking fault and send for station maintenance' after the PDU is received; 2) The VCU detects the main interlocking reported by the PDU, PDU_ InterlockSts =2, and controls the vehicle to lower high voltage after the fault is mature; 3) The VCU detects the PDU and reports primary and secondary interlocking, PDU_ InterlockSts =3, controls the vehicle to be under high voltage after the fault is mature, sends a signal VCU_ InterlockSts =1, cuts off all high voltage accessory relays after the PDU is received, and prompts 'secondary interlocking fault and send for station maintenance' after the PDU is received; 4) The VCU detects PDU report pdu_ FaultGrade =3, and the PDU detects relay stuck with 3-stage fault, and the VCU controls the vehicle to pull down high voltage after stopping.

Description

High-voltage insulation or interlocking fault processing system and processing method for pure electric vehicle Technical Field The invention relates to a high-voltage insulation or interlocking fault processing system and a processing method for a pure electric vehicle, and belongs to the technical field of high-voltage safety control of pure electric vehicles. Background The high-voltage system (power battery, driving motor, high-voltage distribution box, etc.) of the pure electric automobile is a core component of the automobile. Because the voltage of the high-voltage system is generally hundreds of volts, once insulation failure (namely unexpected conduction occurs between the high-voltage power supply and the chassis of the vehicle body) or disconnection of a high-voltage interlocking loop (generally used for monitoring the in-place state of the high-voltage connector) occurs, serious safety accidents such as electric shock, fire and the like are extremely easy to occur. Therefore, the national standard and industry specification require a complete Vehicle Controller (VCU) or a Battery Management System (BMS) to have functions of real-time monitoring and safety response to the faults. Currently, for high voltage insulation faults or interlocking faults, the existing mainstream control strategy usually adopts a one-cut emergency processing mechanism, namely when the system detects the serious faults, in order to rapidly cut off the high voltage electric energy source to prevent risk expansion, the whole vehicle controller immediately sends a disconnection instruction to the high voltage contactor, or after the vehicle meets the condition that the vehicle speed is lower than a set threshold value (such as 5km/h or 0 km/h), high voltage power-down operation is executed. The partially conservative strategy even directly requests immediate opening of the main relay, irrespective of the current operating state of the vehicle. However, the inventors found that the above existing fault handling strategy has the following technical drawbacks in practical applications: First, there is a safe secondary risk, During high-speed running of the vehicle, if high voltage is immediately forced down due to insulation or interlocking failure, the driving motor loses power, and the steering assist pump (EPS) and the brake assist pump (vacuum pump or electronic assist) fail. Although the regulation requires mechanical steering and braking, under the condition of no power, a driver needs to apply far-beyond-normal operating force to control the vehicle, and serious secondary traffic accidents are extremely easy to be caused under high-speed road conditions or emergency avoidance scenes. Second, the variability of the scene is ignored, resulting in a vehicle "sit" risk, Existing strategies typically only perform the low high voltage after "vehicle speed is zero". However, if the failure is triggered when the vehicle is in a red light, slowly following a car or just driving into a complex road condition such as a tunnel/overpass, the vehicle is successfully put under high pressure after stopping, but the vehicle cannot run under high pressure again after that. This results in the vehicle being forced to stop in the centre of the road (especially at the intersection or in the tunnel), both causing traffic jams and exposing the faulty vehicle itself to a very high risk of being knocked-down, and increasing the difficulty and risk of subsequent rescue trailers. Third, the lack of hierarchical processing and failure recovery mechanisms, The prior art generally treats insulation faults and interlock faults as "irreversible" catastrophic failures, permanently locking the high voltage shut off state once triggered. However, in practical engineering applications, a part of the interlocking failure may be caused by a transient virtual joint of vibration of the plug connector, and a part of the insulation failure may be recovered under a specific working condition (such as a reduced humidity). The existing strategy cannot identify the timeliness and persistence of the fault, resulting in unnecessary unintended parking. Disclosure of Invention In view of the above, it is an object of the present invention to provide a system and a method for handling high voltage insulation or interlock faults of a pure electric vehicle, which solve at least the problems mentioned in the background art. The invention aims at realizing the following technical scheme: The high-voltage insulation or interlocking fault processing system of the pure electric vehicle is based on a VCU whole vehicle controller and an MCU electric drive control unit, a BMS battery management system and an IC instrument which are electrically connected with the VCU whole vehicle controller, and comprises a four-in-one assembly, wherein the four-in-one assembly is connected with a BMS power battery, a quick charge and a driving motor through a main interlocking loop, the four-in-