New energy electric vehicle and safe towing method thereof

Abstract

According to the new energy electric vehicle and the safe trailer method thereof, a trailer instruction is set in a vehicle control unit of the new energy electric vehicle, and the method comprises the following steps that a motor controller judges whether the trailer instruction sent by the vehicle control unit is received or not, and if yes, a trailer mode is started; if not, responding to a control mode corresponding to the whole vehicle; in the trailer mode, the vehicle control unit instructs to start controller heat dissipation water circulation, and whether a heat dissipation fan is started or not is selected according to the current trailer mode; and the motor controller judges and enters a low-speed trailer mode or a free trailer mode according to the vehicle key gear and the DCDC starting state, and outputs and displays the highest allowable trailer speed. The invention further provides the new energy electric vehicle which adopts the new energy electric vehicle safety trailer method to carry out trailer operation. A standby high-voltage power supply needed in the prior art is not needed, the safety risk existing in the trailer process is avoided, and the professional technical requirement for trailer personnel is lowered.

Description

Technical Field

[0001] The present invention relates to a new energy vehicle, in particular to a new energy electric vehicle capable of realizing whole vehicle system control and a safe towing method thereof. Background Art

[0002] Existing methods for towing new energy vehicles primarily rely on mechanical disassembly: removing the drive shaft half to disconnect the motor from the drive wheel; and removing the motor's three-phase power wiring harness to disconnect the motor from the controller's high voltage. This method is cumbersome to implement, requiring specialized disassembly personnel with a certain level of expertise. They are often unable to reach the fault site immediately, preventing the vehicle from being quickly towed for repair. Due to the motor's mounting layout on the vehicle, removing the motor's three-phase power wiring harness at the fault site is unlikely to be feasible without a repair trench and other specialized tools, due to space limitations within the vehicle.

[0003] When the towing process begins, when the DC bus voltage reaches the preset voltage threshold, the high-voltage backup power supply automatically starts operating, activating the motor controller to start operating. The motor controller then determines whether there is a fault that could affect towing. If no fault exists, the motor controller activates the safe towing function. If a fault exists, the motor controller enters a safe state and sends a warning signal to the vehicle controller. This requires a backup high-voltage power supply, which increases vehicle manufacturing costs and affects vehicle layout space. Furthermore, the vehicle must be controlled based on the current DC bus voltage value during the towing process, resulting in poor operability in actual use and safety risks. Because passengers are not allowed to sit in a faulty new energy vehicle during towing, if the controller fails during towing, the personnel on the towing vehicle will not be aware of the problem. This can result in the faulty new energy vehicle being forced to tow without meeting the required towing conditions, causing damage to the motor controller. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a new energy electric vehicle and a safe towing method thereof in view of the above-mentioned defects of the prior art.

[0005] To achieve the above-mentioned object, the present invention provides a method for safely towing a new energy electric vehicle, wherein a towing instruction is provided in a vehicle controller of the new energy electric vehicle, and the method comprises the following steps:

[0006] S100, the motor controller determines whether it has received a trailer instruction sent by the vehicle controller, and if so, enters the trailer mode; if not, responds to the control mode corresponding to the vehicle; and

[0007] S200. In trailer mode, the vehicle controller instructs to start the controller cooling water circulation and selects whether to start the cooling fan according to the current trailer mode; the motor controller judges and enters the low-speed trailer mode or the free trailer mode according to the vehicle key gear position and the DCDC opening status, and outputs and displays the maximum allowable trailer speed.

[0008] In the above-mentioned method for safe towing of new energy electric vehicles, the vehicle controller detects the status of the towing button and sends the towing instruction to the motor controller through the CAN network.

[0009] In the above-mentioned new energy electric vehicle safe towing method, the vehicle controller detects the gear position and key switch signal through the IO port, and sends the vehicle key gear position and DCDC opening status to the motor controller through the CAN network.

[0010] In the above-mentioned safe towing method for new energy electric vehicles, when the high-voltage battery of the entire vehicle fails or cannot be supplied with high voltage, the low-speed towing mode is adopted, the motor controller calculates and outputs the maximum allowable towing speed based on the back electromotive force of the drive motor, and the IGBT is not enabled.

[0011] In the above-mentioned method for safe towing of new energy electric vehicles, the maximum permissible towing speed in the low-speed towing mode is:

[0012] n=v*0.8 / k,

[0013] Where n is the speed of the drive motor in r / min; v is the rated operating voltage of the motor controller; and k is the no-load back electromotive force coefficient of the motor.

[0014] In the above-mentioned method for safe towing of new energy electric vehicles, when the whole vehicle can be normally supplied with high voltage, the free towing mode is adopted, the motor controller outputs the maximum trailer allowable speed according to the maximum operating speed of the drive motor, turns on the IGBT enable, and performs vector control on the drive motor at the same time.

[0015] In the above-mentioned method for safe towing of new energy electric vehicles, the IGBT is enabled so that the IGBT performs PWM wave open-tube operation.

[0016] The above-mentioned method for safe towing of new energy electric vehicles further includes: when the motor controller fails, the entire vehicle enters a prohibited towing mode, and the maximum allowed towing speed is 0.

[0017] The above-mentioned new energy electric vehicle safe towing method, wherein the low-speed towing mode and the free towing mode both include towing trailer and lifting trailer, wherein the towing trailer is towed using a tow rope, and the towed vehicle has four wheels on the ground; wherein the lifting trailer is used, the front two wheels of the towed vehicle are lifted up and suspended in the air, and only the rear two wheels are on the ground.

[0018] In order to better achieve the above-mentioned purpose, the present invention also provides a new energy electric vehicle, wherein the above-mentioned new energy electric vehicle safe towing method is used to perform towing operations.

[0019] The technical effects of the present invention are:

[0020] The present invention does not require a high-voltage backup battery, which solves the problem of requiring a backup high-voltage power supply in the prior art and avoids the safety risks in the towing process. It does not require high professional and technical requirements for towing personnel. New towing instructions are added through the VCU, and the MCU enters the relevant towing mode and feeds back the maximum safe allowable towing speed to the towing personnel. The towing personnel can tow the vehicle as required, which improves the towing efficiency of the faulty vehicle and reduces the professional and technical requirements of the towing personnel. According to the fault conditions of the entire vehicle, a low-speed towing mode and a free towing mode are set. In different modes, the motor controller executes different control strategies to ensure the safety of towing and avoid secondary damage to the faulty vehicle during the towing process.

[0021] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments, but this does not limit the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a working principle diagram of a method for safely towing a new energy electric vehicle according to an embodiment of the present invention;

[0023] Figure 2 This is a structural block diagram of a new energy electric vehicle according to an embodiment of the present invention.

[0024] Among them, the reference numerals

[0025] 1Vehicle Controller

[0026] 2 Motor Controller

[0027] 3 drive motor

[0028] 4 high-voltage batteries

[0029] 5DCDC

[0030] 6 meters

[0031] 7 gears

[0032] 8 key switches

[0033] 9 trailer button

[0034] 10 drive shaft

[0035] 11 axles

[0036] 12 wheels DETAILED DESCRIPTION

[0037] The structural principle and working principle of the present invention are described in detail below with reference to the accompanying drawings:

[0038] See also Figure 1 , Figure 1 The working principle diagram of the safe towing method for a new energy electric vehicle according to one embodiment of the present invention is as follows: The safe towing method for a new energy electric vehicle according to the present invention includes the following steps:

[0039] Step S100: The motor controller determines whether it has received a trailer instruction sent by the vehicle controller. If so, it enters the trailer mode; if not, it responds to the control mode corresponding to the vehicle; and

[0040] Step S200: In trailer mode, the vehicle controller 1 instructs to start the controller cooling water circulation and selects whether to start the cooling fan according to the current trailer mode; the motor controller 2 judges and enters the low-speed trailer mode or the free trailer mode according to the vehicle key gear 7 and the DCDC5 opening status, and outputs and displays the maximum allowable speed of the trailer.

[0041] The vehicle controller 1 detects the status of the trailer button 9 and sends the trailer command to the motor controller 2 via the CAN network. The vehicle controller 1 detects the gear position 7 and key switch 8 signals via the IO port and sends the vehicle key gear position 7 and DCDC5 on-state status to the motor controller 2 via the CAN network. Both the low-speed trailer mode and the free trailer mode include towing and lifting trailers. Towing trailers use a tow rope with all four wheels of the towed vehicle on the ground. Lifting trailers have the towed vehicle's front two wheels suspended in the air, with only the rear two wheels on the ground.

[0042] When the vehicle's high-voltage battery 4 fails or cannot be supplied with high voltage, the low-speed towing mode is adopted. The motor controller 2 calculates and outputs the maximum trailer speed allowed based on the back electromotive force of the drive motor 3, and the IGBT is disabled. The maximum trailer speed allowed in the low-speed towing mode is:

[0043] n=v*0.8 / k,

[0044] Where n is the motor speed in r / min; v is the rated operating voltage of motor controller 2; and k is the motor no-load back electromotive force coefficient.

[0045] When the vehicle can normally receive high voltage, the free towing mode is used. The motor controller 2 outputs the maximum permitted towing speed based on the maximum operating speed of the drive motor 3, activates the IGBT enable, and simultaneously performs vector control on the motor. The IGBT enable function allows the IGBT to operate in PWM mode. In other words, free towing mode requires the following conditions: the faulty vehicle can receive high voltage, the motor controller 2 is fault-free, the IGBT of the motor controller 2 is enabled, and the VCU can enter ready mode. Only when these conditions are met can towing be performed.

[0046] In this embodiment, the following may also be included: when the motor controller 2 fails, the entire vehicle enters a towing prohibition mode, and the maximum trailer-allowed speed in the towing prohibition mode is 0.

[0047] like Figure 1 As shown, Motor Controller 2 determines whether it has received a trailer command. If not, it responds normally to other VCU commands. If trailering is required, it then checks Gear Position 7. If Gear Position 7 is On, the VCU activates the controller's cooling water circulation and turns off the cooling fan. Motor Controller 2 then provides feedback indicating low-speed trailering mode and the maximum permitted trailering speed. If Gear Position 7 is Ready, the MCU is checked for a fault. If so, the VCU activates the controller's cooling water circulation and turns off the cooling fan. Motor Controller 2 then provides feedback indicating trailering disable mode and the maximum permitted trailering speed are 0. If not, the VCU then determines whether DCDC5 is enabled. If DCDC5 is not enabled, the VCU activates the controller's cooling water circulation and turns off the cooling fan. Motor Controller 2 then provides feedback indicating low-speed trailering mode and the maximum permitted trailering speed. If DCDC5 is enabled, the VCU activates the controller's cooling water circulation and turns on the cooling fan. The MCU then provides feedback indicating free trailering mode and the maximum permitted trailering speed. In this embodiment, the VCU sends the following commands to the motor controller 2: a. Trailer Enable Signal: 0: Off; 1: On; b. DCDC5 Operating Status: 0: Stopped; 1: Operating; c. Vehicle Status: 0: Off; 1: On; 2: Ready. The motor controller 2 provides the following status feedback to the VCU: a. Trailer Mode: 0: Not in Trailer Mode; 1: Low-Speed ​​Trailer Mode; 2: Free Trailer Mode; 3: Trailer Disabled; b. Maximum Allowable Trailer Speed.

[0048] See also Figure 2 , Figure 2This is a block diagram of the structure of a new energy electric vehicle according to one embodiment of the present invention. The new energy electric vehicle of the present invention utilizes the aforementioned safe towing method for new energy electric vehicles for towing operations. The vehicle controller 1 is connected to the motor controller 2, the DC-DC converter 5, and the instrument 6 via CAN communication lines, and is connected to the gear position 7, the key switch 8, and the towing button 9 via IO port detection lines. The high-voltage battery 4 is connected to the DC-DC converter 5 and the motor controller 2, respectively. The motor controller 2 is connected to the drive motor 3, which is connected to the axle 11 via the vehicle's mechanical transmission shaft 10. The drive motor 3 ultimately transmits power to the wheels 12 through the axle 11.

[0049] During operation, the VCU (Vehicle Controller Unit 1) detects the status of the gear position 7, key switch 8, and trailer button 9 via the IO port and transmits this information to the motor controller 2 via the CAN network. The instrument cluster 6 receives vehicle fault messages, trailer mode, and maximum safe towing speed from the VCU via the CAN network. The DC-DC converter 5 receives VCU operating instructions via the CAN network and transmits its operating status to the VCU via the CAN network. The high-voltage battery 4 also receives VCU operating instructions via the CAN network and transmits its operating status to the VCU via the CAN network. The motor controller 2 receives control commands such as the trailer enable signal from the MCU, the DCDC5 operating status, and the vehicle key status via the CAN network. The motor controller 2 then provides the VCU with feedback on the trailer mode and maximum permitted trailer speed via the CAN network. Before towing, the trailer button 9 must be activated, and the instrument cluster 6 will display the maximum permitted trailer speed. Safe towing is achieved by not exceeding the maximum operating speed during towing.

[0050] The present invention can tow and lift a new energy vehicle that has a breakdown. During the towing process, there is power transmission between the drive motor 3 and the grounded wheels. Towing a trailer uses a tow rope to tow the vehicle, with all four wheels of the towed vehicle on the ground. When lifting a trailer, the front two wheels of the towed vehicle are lifted and suspended in the air, leaving only the rear two wheels on the ground. The towing operation is completed by the VCU and MCU. The VCU is the vehicle controller 1, and the MCU is the motor controller. The VCU is configured with a towing command. In towing mode, the motor controller 2 determines whether to enter low-speed towing mode or free towing mode based on the vehicle key position 7 and the DCDC5 (DC-to-DC converter) activation status, and determines the maximum permissible towing speed. The towing command is transmitted by the VCU (vehicle controller 1) to the motor controller 2 via the CAN network after detecting the status of the trailer button 9. The VCU (vehicle controller 1) detects the vehicle key position 7 and the DCDC5 activation status through the IO port and detects the position 7 and key switch 8 signals, which are then transmitted to the motor controller 2 via the CAN network. If the vehicle's high-voltage battery 4 fails or other serious faults prevent high voltage from being applied, the trailer operates in low-speed towing mode. The maximum permissible trailer speed is calculated by the motor controller 2 based on the back electromotive force of the drive motor 3, which must not exceed 80% of the rated operating voltage. The IGBT is disabled in this mode. In free towing mode, when the vehicle can normally apply high voltage, the maximum permissible trailer speed is the maximum operating speed of the motor. At this point, the motor controller 2 must enable the IGBT and perform vector control of the motor. IGBT enablement involves the IGBT operating in PWM mode. Vector control is a mature motor control technology.

[0051] The present invention does not require a high-voltage backup battery, which solves the problem of requiring a backup high-voltage power supply in the prior art and avoids the safety risks in the towing process. It does not require high professional and technical requirements for towing personnel. New towing instructions are added through the VCU, and the MCU enters the relevant towing mode and feeds back the maximum safe allowable towing speed to the towing personnel. The towing personnel can tow the vehicle as required, which improves the towing efficiency of the faulty vehicle and reduces the professional and technical requirements of the towing personnel. According to the fault conditions of the entire vehicle, a low-speed towing mode and a free towing mode are set. In different modes, the motor controller executes different control strategies to ensure the safety of towing and avoid secondary damage to the faulty vehicle during the towing process.

[0052] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art may make various corresponding changes and modifications based on the present invention, but these corresponding changes and modifications should all fall within the scope of protection of the claims attached to the present invention.

Claims

1. A method for safely towing a new energy electric vehicle, wherein the vehicle controller of the new energy electric vehicle is equipped with a towing instruction, characterized in that: The steps include: S100, the motor controller determines whether it has received a trailer instruction sent by the vehicle controller, and if so, enters the trailer mode; if not, responds to the control mode corresponding to the vehicle; and S200. In trailer mode, the vehicle controller instructs to start the controller cooling water circulation and selects whether to start the cooling fan according to the current trailer mode; the motor controller judges and enters the low-speed trailer mode or the free trailer mode according to the vehicle key gear position and the DCDC opening status, and outputs and displays the maximum allowable trailer speed.

2. The method for safely towing a new energy electric vehicle according to claim 1, wherein: The vehicle controller detects the state of the trailer button and sends the trailer instruction to the motor controller through the CAN network.

3. The method for safely towing a new energy electric vehicle according to claim 1, wherein: The vehicle controller detects the gear position and key switch signal through the IO port, and sends the vehicle key gear position and DCDC opening status to the motor controller through the CAN network.

4. The method for safely towing a new energy electric vehicle according to claim 1, wherein: When the high-voltage battery of the vehicle fails or cannot be supplied with high voltage, the low-speed towing mode is adopted, the motor controller calculates and outputs the maximum trailer allowable speed based on the back electromotive force of the drive motor, and the IGBT is not enabled.

5. The method for safely towing a new energy electric vehicle according to claim 4, characterized in that: The maximum trailer speed allowed in the low-speed trailer mode is: n=v*0.8 / k, Where n is the speed of the drive motor in r / min; v is the rated operating voltage of the motor controller; and k is the no-load back electromotive force coefficient of the motor.

6. The method for safely towing a new energy electric vehicle according to claim 1, wherein: When the vehicle can be normally supplied with high voltage, the free trailer mode is adopted, and the motor controller outputs the maximum trailer allowable speed according to the maximum operating speed of the drive motor, turns on the IGBT enable, and performs vector control on the drive motor at the same time.

7. The method for safely towing a new energy electric vehicle according to claim 6, characterized in that: The IGBT is enabled so that the IGBT performs PWM wave open-tube operation.

8. The method for safely towing a new energy electric vehicle according to claim 1, wherein: Also includes: When the motor controller fails, the vehicle enters a towing prohibited mode, and the maximum trailer allowed speed is 0.

9. The method for safely towing a new energy electric vehicle according to claim 1, wherein: The low-speed towing mode and the free towing mode both include towing a trailer and lifting a trailer. When towing a trailer, a tow rope is used to tow the vehicle, and the four wheels of the towed vehicle are on the ground; when lifting a trailer, the front two wheels of the towed vehicle are lifted and suspended in the air, and only the rear two wheels are on the ground.

10. A new energy electric vehicle, characterized in that: The towing operation is performed using the new energy electric vehicle safe towing method described in any one of claims 1 to 9.

Images