A hierarchical control method and system for energy recovery of pure electric heavy-duty commercial vehicles

Abstract

The present invention discloses a hierarchical energy recovery control method and system for a pure electric heavy-duty commercial vehicle, relating to the field of electric vehicle technology. The control method of the present invention comprises the following steps: determining whether the vehicle's driving state is coasting or braking based on the vehicle's quasi-state; confirming the energy recovery set torque value based on the vehicle's driving state; determining whether the energy recovery set torque value exceeds the limit and whether the ABS is activated; and outputting the final energy recovery set torque value. The present invention adds a handle control switch to enhance driver convenience, while optimizing the energy recovery level based on the drive motor characteristics and the drive axle directional torque limit to ensure vehicle smoothness and efficiency, as well as the service life of the vehicle's drive axle.

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicles, and in particular to a hierarchical control method and system for energy recovery of a pure electric heavy-duty commercial vehicle. Background Art

[0002] Pure electric heavy-duty commercial vehicles adapt to diverse operating conditions, and a constant level of regenerative braking cannot adequately meet the demands of energy-efficient driving. Vehicles with graded regenerative braking can recycle more energy, especially during long, heavily loaded downhill descents. However, increasing regenerative braking increases the impact and wear on the rear axle gears, potentially leading to high temperatures in the drive motor due to inefficient operation.

[0003] Therefore, a hierarchical control method and system for energy recovery of pure electric heavy-duty commercial vehicles are proposed to ensure the service life of the drive axle and drive motor. Summary of the Invention

[0004] The purpose of the present invention is to propose a hierarchical control method and system for energy recovery of a pure electric heavy-duty commercial vehicle, which improves the convenience of driver operation by adding a handle control switch, and optimizes the energy recovery size according to the characteristics of the drive motor and the directional torque limit of the drive axle, thereby ensuring the smoothness and efficiency of the vehicle and the service life of the vehicle drive axle.

[0005] The technical solution adopted in the present invention is as follows:

[0006] The present invention is a hierarchical control method for energy recovery of a pure electric heavy-duty commercial vehicle, comprising the following steps:

[0007] The vehicle status of the electric vehicle is determined to be in the sliding or braking state;

[0008] According to the vehicle's driving status, confirm the energy feedback set torque value;

[0009] Determine whether the energy feedback set torque value exceeds the limit and whether the ABS is activated;

[0010] Output the final energy feedback set torque value.

[0011] Furthermore, the determination of the vehicle driving state is specifically as follows:

[0012] The vehicle is judged to be coasting. Specifically, if the vehicle speed is greater than 3 km / h, the accelerator pedal is released, and the brake pedal is not depressed, the control system performs energy recovery.

[0013] The vehicle's driving state is determined to be braking. Specifically, when the vehicle speed is greater than 3 km / h and the accelerator pedal is released, the brake pedal is depressed and the control system performs energy recovery.

[0014] Furthermore, the energy feedback set torque value is determined according to the vehicle driving state, specifically: the energy feedback set torque value is determined according to whether the brake pedal is depressed,

[0015] When the brake pedal is not depressed, the coasting energy feedback set torque value = the energy recovery characteristic curve corresponding to the motor speed * the energy recovery coefficient corresponding to the handle operation switch * the energy recovery coefficient corresponding to the gearbox gear position;

[0016] When the brake pedal is depressed, the braking energy feedback set torque value calculated according to the pedal depth is compared with the coasting energy feedback set torque value to obtain the maximum energy feedback set torque value.

[0017] Furthermore, the confirmation of whether the energy feedback set torque value exceeds the limit is specifically as follows:

[0018] Determine whether the energy feedback set torque value exceeds the motor's allowable feedback power. If it exceeds the limit, the energy feedback set torque value is modified to the motor's maximum allowable value.

[0019] Determine whether the energy feedback set torque value exceeds the battery's allowable feedback power. If it exceeds the limit, the energy feedback set torque value is modified to the battery's maximum allowable value.

[0020] Furthermore, the determination of whether the ABS is activated, that is, whether the braking system allows energy feedback, is performed. If the ABS is activated and the braking system does not allow energy feedback, the energy feedback set torque value is modified to 0 N.m;

[0021] The energy feedback set torque value is within the limit and the ABS is not activated, that is, the output vehicle is in a coasting or braking state. The energy feedback set torque value.

[0022] A hierarchical energy recovery control system for a pure electric heavy-duty commercial vehicle, comprising a handle control switch, a vehicle controller, a motor controller, a drive motor, an AMT gearbox, a drive axle, and a drive wheel.

[0023] The handle control switch controls the vehicle gear position, and each gear position corresponds to an energy recovery coefficient. The AMT transmission has 4 gears, and each gear position corresponds to an energy recovery coefficient;

[0024] The vehicle controller collects the gear position signal of the handle operating switch. After the vehicle controller recognizes the gear position signal of the handle operating switch, it sends a control command to the motor controller through CAN communication in accordance with the above control method. The motor controller executes the control command and drives the motor to the power generation state. The output torque direction is opposite to the motor operation direction. The torque is transmitted to the drive wheel through the AMT gearbox and drive axle to realize vehicle energy recovery.

[0025] Furthermore, the handle control switch controls the gear position by connecting different resistors, and the vehicle controller collects the handle control switch resistance signal, that is, when the resistance is R0, it is OFF gear, when the handle control switch is connected to the resistance R1, it is 1 gear, when the handle control switch is connected to the resistance R2, it is 2 gear, when the handle control switch is connected to the resistance R3, it is 3 gear, when the handle control switch is connected to the resistance R4, it is 4 gear, when the handle control switch is connected to the resistance R5, it is 5 gear, and when the handle control switch is connected to the resistance R6, it is 6 gear.

[0026] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0027] 1. The present invention provides a hierarchical energy recovery control method and system for a pure electric heavy-duty commercial vehicle. When the gearbox is in different gears, the vehicle uses different energy recovery levels to ensure that the directional torque during energy recovery does not exceed the limit of the directional torque of the drive axle. That is, when the vehicle controller recognizes that the gear is in a lower gear, it reduces the energy recovery coefficient to ensure that the directional torque limit of the drive axle is not exceeded, effectively protecting the service life of the drive axle.

[0028] 2. The present invention provides a hierarchical control method and system for energy recovery in pure electric heavy-duty commercial vehicles. By driving the motor feed state efficiency MAP diagram, the energy recovery characteristic curve corresponding to the motor speed is selected to be closer to the high-efficiency zone, thereby obtaining a more optimal motor feedback characteristic curve, avoiding high-torque energy recovery at lower speeds, improving vehicle smoothness, and increasing energy recovery efficiency.

[0029] 3. The present invention provides a hierarchical energy recovery control method and system for pure electric heavy-duty commercial vehicles. This method effectively solves the problem of inconsistent energy recovery requirements for pure electric heavy-duty commercial vehicles under various operating conditions. By adding a handle control switch, the driver's operation convenience is improved. At the same time, the energy recovery size is optimized according to the characteristics of the drive motor and the directional torque limit of the drive axle, ensuring the vehicle's smoothness and efficiency, as well as the service life of the vehicle's drive axle. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be considered as limiting the scope. A person of ordinary skill in the art can also derive other relevant drawings based on these drawings without inventive effort, among which:

[0031] Figure 1 It is a schematic flow chart of the control method of the present invention;

[0032] Figure 2 It is the gear control diagram of the handle operating switch;

[0033] Figure 3 It is the feeding state efficiency MAP diagram of the drive motor. DETAILED DESCRIPTION

[0034] In order to make the objectives, technical solutions, and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present invention and are not intended to limit the present invention. That is, the embodiments described herein are only some embodiments of the present invention, not all embodiments. Generally, the components of the embodiments of the present invention described and illustrated in the drawings herein may be arranged and designed in various different configurations.

[0035] It should be noted that the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements that are inherent to such process, method, article or apparatus.

[0036] It should be understood that the terms "up", "down", "left", "right", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, it should not be understood as a limitation on the present invention.

[0037] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0038] Example 1

[0039] like Figure 1 As shown, the present invention is a hierarchical control method for energy recovery of a pure electric heavy-duty commercial vehicle, comprising the following steps:

[0040] The vehicle status of the electric vehicle is determined to be in the sliding or braking state;

[0041] According to the vehicle's driving status, confirm the energy feedback set torque value;

[0042] Determine whether the energy feedback set torque value exceeds the limit and whether the ABS is activated;

[0043] Output the final energy feedback set torque value.

[0044] Preferably, the determination of the vehicle driving state is specifically as follows:

[0045] The vehicle is judged to be coasting. Specifically, if the vehicle speed is greater than 3 km / h, the accelerator pedal is released, and the brake pedal is not depressed, the control system performs energy recovery.

[0046] The vehicle's driving state is determined to be braking. Specifically, when the vehicle speed is greater than 3 km / h and the accelerator pedal is released, the brake pedal is depressed and the control system performs energy recovery.

[0047] Preferably, the energy feedback set torque value is determined according to the vehicle driving state, specifically: the energy feedback set torque value is determined according to whether the brake pedal is depressed,

[0048] When the brake pedal is not depressed, the coasting energy feedback set torque value = the energy recovery characteristic curve corresponding to the motor speed * the energy recovery coefficient corresponding to the handle operation switch * the energy recovery coefficient corresponding to the gearbox gear position;

[0049] When the brake pedal is depressed, the braking energy feedback set torque value calculated according to the pedal depth is compared with the coasting energy feedback set torque value to obtain the maximum energy feedback set torque value.

[0050] The relationship between motor speed and torque is as follows: as the motor speed increases, its torque first increases and then decreases. The feed state efficiency MAP of the drive motor is as follows: Figure 3 As shown in the figure, by using the drive motor feeding state efficiency MAP diagram, the present invention selects the motor speed corresponding energy recovery characteristic curve closer to the high efficiency zone. The values ​​of the motor speed corresponding energy recovery characteristic curve of the present invention are shown in Table 1. The present invention can avoid high torque energy recovery at lower speeds (<500rpm). The use of high torque energy recovery at lower speeds can easily cause vehicle unevenness and low energy recovery efficiency, which is uneconomical.

[0051] Table 1, Motor speed corresponding to energy recovery characteristic curve value

[0052] Speed ​​(rpm) 0 100 200 300 400 500 Torque (Nm) 0 500 800 1100 1400 1700 Speed ​​(rpm) 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 Torque (Nm) 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 Speed ​​(rpm) 1800 1900 2000 2100 2200 2300 2400 2500 2600 2700 2800 2900 3000 Torque (Nm) 1900 1800 1700 1600 1500 1400 1300 1200 1100 1000 900 800 700

[0053] In the present invention, the energy recovery coefficient corresponding to the handle operation switch is shown in Table 2.

[0054] Table 2, Energy recovery coefficient corresponding to the handle operation switch

[0055]

[0056] In the present invention, the energy recovery coefficient corresponding to the gear position of the transmission is shown in Table 3 (Note: the wheel side torque limit of the current design vehicle model is 21000N.m).

[0057] Table 3, Energy recovery coefficient corresponding to gearbox gear

[0058]

[0059]

[0060] The present invention utilizes different energy recovery levels for different gear positions, ensuring that the directional torque during energy recovery does not exceed the drive axle's directional torque limit. Specifically, the vehicle controller reduces the energy recovery coefficient when the vehicle is in a lower gear position, ensuring that the drive axle's directional torque limit is not exceeded, effectively protecting the drive axle's service life.

[0061] Preferably, the step of confirming whether the energy feedback set torque value exceeds the limit is as follows:

[0062] Determine whether the energy feedback set torque value exceeds the motor's allowable feedback power. If it exceeds the limit, the energy feedback set torque value is modified to the motor's maximum allowable value.

[0063] Determine whether the energy feedback set torque value exceeds the battery's allowable feedback power. If it exceeds the limit, the energy feedback set torque value is modified to the battery's maximum allowable value.

[0064] Preferably, the judgment of whether the ABS is activated, that is, whether the braking system allows energy feedback, is performed. If the ABS is activated and the braking system does not allow energy feedback, the energy feedback set torque value is modified to 0 N.m;

[0065] The energy feedback set torque value is within the limit and the ABS is not activated, that is, the output vehicle is in a coasting or braking state. The energy feedback set torque value.

[0066] The control method of the present invention is divided into two types according to the vehicle driving state, namely, coasting state and braking state.

[0067] (1) Sliding state

[0068] The electric vehicle is in READY state. Confirm that the vehicle speed is > 3 km / h and the accelerator pedal is released. Confirm whether the brake pedal is depressed. When the brake pedal is not depressed, the coasting energy feedback set torque value = the energy recovery characteristic curve corresponding to the motor speed * the energy recovery coefficient corresponding to the handle operation switch * the energy recovery coefficient corresponding to the transmission gear position; confirm whether the energy feedback set torque value exceeds the limit. If the energy feedback set torque value exceeds the allowable feedback power of the motor, modify the energy feedback set torque value to the maximum value allowed by the motor. If the energy feedback set torque value exceeds the allowable feedback power of the battery, modify the energy feedback set torque value to the maximum value allowed by the battery. Confirm whether the ABS is activated. If the ABS is activated, that is, the braking system does not allow energy feedback, modify the energy feedback set torque value to 0 N.m. If the energy feedback set torque value does not exceed the limit and the ABS is not activated, output the energy feedback set torque value.

[0069] (2) Braking status

[0070] The electric vehicle is in READY state, confirming that the vehicle speed is greater than 3km / h and the accelerator pedal is released, and confirming whether the brake pedal is depressed. When the brake pedal is depressed, the braking energy feedback set torque value calculated according to the pedal depth is compared with the coasting energy feedback set torque value to obtain the maximum energy feedback set torque value. After the energy feedback set torque value is subjected to the above-mentioned over-limit confirmation and ABS activation confirmation, the final energy feedback set torque value is output.

[0071] Example 2

[0072] This embodiment is a further explanation of the present invention.

[0073] A hierarchical energy recovery control system for a pure electric heavy-duty commercial vehicle, comprising a handle control switch, a vehicle controller, a motor controller, a drive motor, an AMT gearbox, a drive axle, and a drive wheel.

[0074] The handle control switch controls the vehicle gear position, and each gear position corresponds to an energy recovery coefficient. The specific data is shown in Table 1. The AMT transmission has 4 gears, and each gear position corresponds to an energy recovery coefficient; the specific data is shown in Table 3.

[0075] The vehicle controller collects the gear position signal of the handle operating switch. After the vehicle controller recognizes the gear position signal of the handle operating switch, it sends a control command to the motor controller through CAN communication in accordance with the above control method. The motor controller executes the control command and drives the motor to the power generation state. The output torque direction is opposite to the motor operation direction. The torque is transmitted to the drive wheel through the AMT gearbox and drive axle to realize vehicle energy recovery.

[0076] Preferably, Figure 2 As shown, the handle control switch controls the gear position by connecting different resistors, and the vehicle controller collects the handle control switch resistance signal, that is, when the resistance is R0, it is OFF gear, when the handle control switch is connected to the resistance R1, it is 1 gear, when the handle control switch is connected to the resistance R2, it is 2 gear, when the handle control switch is connected to the resistance R3, it is 3 gear, when the handle control switch is connected to the resistance R4, it is 4 gear, when the handle control switch is connected to the resistance R5, it is 5 gear, and when the handle control switch is connected to the resistance R6, it is 6 gear.

[0077] The present invention effectively solves the problem of inconsistent energy recovery requirements for pure electric heavy-duty commercial vehicles under various operating conditions. It improves the driver's convenience by adding a handle control switch, and optimizes the energy recovery size according to the drive motor characteristics and the drive axle directional torque limit, ensuring the vehicle's smoothness and efficiency, as well as the service life of the vehicle's drive axle.

[0078] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be conceived by a person skilled in the art within the technical scope disclosed by the present invention without inventive effort should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection defined in the claims.

Claims

1. A hierarchical control method for energy recovery of a pure electric heavy-duty commercial vehicle, characterized by: The following steps are involved: The vehicle status of the electric vehicle is determined to be in the sliding or braking state; According to the vehicle's driving status, confirm the energy feedback set torque value; Determine whether the energy feedback set torque value exceeds the limit and whether the ABS is activated; Output the final energy feedback set torque value; According to the vehicle's driving state, the energy feedback set torque value is determined. Specifically, the energy feedback set torque value is determined according to whether the brake pedal is depressed. When the brake pedal is not depressed, the coasting energy feedback set torque value = the energy recovery characteristic curve corresponding to the motor speed * the energy recovery coefficient corresponding to the handle operation switch * the energy recovery coefficient corresponding to the gearbox gear position; When the brake pedal is depressed, the braking energy feedback set torque value calculated according to the pedal depth is compared with the coasting energy feedback set torque value to obtain the maximum energy feedback set torque value.

2. The method for hierarchical control of energy recovery for a pure electric heavy-duty commercial vehicle according to claim 1, characterized in that: The determination of the vehicle driving state is specifically as follows: The vehicle is judged to be coasting. Specifically, if the vehicle speed is greater than 3 km / h, the accelerator pedal is released, and the brake pedal is not depressed, the control system performs energy recovery. The vehicle's driving state is determined to be braking. Specifically, when the vehicle speed is greater than 3 km / h and the accelerator pedal is released, the brake pedal is depressed and the control system performs energy recovery.

3. The method for hierarchical control of energy recovery for a pure electric heavy-duty commercial vehicle according to claim 1, characterized in that: The confirmation of whether the energy feedback set torque value exceeds the limit is specifically as follows: Determine whether the energy feedback set torque value exceeds the motor's allowable feedback power. If it exceeds the limit, the energy feedback set torque value is modified to the motor's maximum allowable value. Determine whether the energy feedback set torque value exceeds the battery's allowable feedback power. If it exceeds the limit, the energy feedback set torque value is modified to the battery's maximum allowable value.

4. The method for hierarchical control of energy recovery for a pure electric heavy-duty commercial vehicle according to claim 3, characterized in that: The judgment of whether the ABS is activated, that is, whether the braking system allows energy feedback, is as follows: if the ABS is activated and the braking system does not allow energy feedback, the energy feedback set torque value is modified to 0 N.m; The energy feedback set torque value is within the limit and the ABS is not activated, that is, the output vehicle is in a coasting or braking state. The energy feedback set torque value.

5. A hierarchical energy recovery control system for a pure electric heavy-duty commercial vehicle, characterized by: The control system includes a handle control switch, a vehicle controller, a motor controller, a drive motor, an AMT gearbox, a drive axle and a drive wheel. The handle control switch controls the vehicle gear position, and each gear position corresponds to an energy recovery coefficient. The AMT transmission has 4 gears, and each gear position corresponds to an energy recovery coefficient; The vehicle controller collects the handle operating switch gear signal. After the vehicle controller recognizes the handle operating switch gear signal, it sends a control command to the motor controller through CAN communication in accordance with the control method described in any one of claims 1 to 4 above. The motor controller executes the control command and drives the motor to the power generation state. The output torque direction is opposite to the motor operation direction. The torque is transmitted to the drive wheel through the AMT gearbox and drive axle to realize vehicle energy recovery.

6. A pure electric heavy-duty commercial vehicle energy recovery hierarchical control system according to claim 5, wherein the handle control switch controls the gear position by connecting different resistors, and the vehicle controller collects the handle control switch resistance signal, that is, when the resistance is R0, it is the OFF gear, when the handle control switch is connected to the resistance R1, it is the 1st gear, when the handle control switch is connected to the resistance R2, it is the 2nd gear, when the handle control switch is connected to the resistance R3, it is the 3rd gear, when the handle control switch is connected to the resistance R4, it is the 4th gear, when the handle control switch is connected to the resistance R5, it is the 5th gear, and when the handle control switch is connected to the resistance R6, it is the 6th gear.

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