Commercial vehicle three-motor system torque distribution intelligent control method and framework

Abstract

The invention relates to an intelligent control method and architecture for torque distribution of a three-motor system of a commercial vehicle, and solves the problems that the torque distribution of the three-motor system does not fully consider comprehensive factors such as use requirements of actual working conditions, utilization of high-efficiency areas of motors, the average service life of the motors, faults of the motors and the like at present. The method includes the following steps that firstly, the actual working condition of a vehicle is recognized; secondly, the minimum working number of a motor is updated; step 3, calculating a required torque motor efficiency value; 4, determining the actual working number of the motor; 5, designing a main and auxiliary motor sequence value motor distribution method; sixthly, specifically distributed working motors are determined; seventhly, the compensation torque is met in the upshift and downshift process; 8, according to the change of the transmission ratio after the upshifting and downshifting, torque compensation is conducted through the transmission ratio, filtering processing and slope limiting are conducted on the output torque, smoothness of the output torque is guaranteed, and the smoothness of the vehicle in the running process is improved. According to the invention, the safety and reliability of the system are improved.

Description

Technical Field

[0001] This invention relates to a control method, specifically to an intelligent control method and architecture for torque distribution in a three-motor system for commercial vehicles. Background Technology

[0002] With the continuous development of new energy commercial vehicle technology, its power system is shifting from the traditional oil-to-electric power transmission system to the central centralized electric drive axle power system and the distributed electric drive axle power system. Currently, the single-motor central centralized electric drive axle cannot meet the needs of high-horsepower commercial vehicles due to size limitations. Dual-motor and tri-motor electric drive axle products have become the preferred power system for high-horsepower new energy commercial vehicles. However, the torque distribution of tri-motor systems is currently only a simple torque distribution, without fully considering the actual operating conditions, the utilization of the motor's high-efficiency range, the average lifespan of the motor, and the comprehensive factors such as motor failure. Therefore, it cannot fully utilize the advantages of the tri-motor system. Summary of the Invention

[0003] This invention designs an intelligent control method and architecture for torque distribution in a three-motor system for commercial vehicles. It achieves optimized torque distribution in the three-motor system, meeting the usage requirements of high-horsepower commercial vehicles. Furthermore, it fully utilizes the high-efficiency operating range of the motors to improve the energy-saving level of the three-motor system. It intelligently allocates the start-stop and torque distribution ratio of each motor in the three-motor system based on the average service life of the motors, thereby improving the overall operating life of the motor system. By replacing the motor in case of motor failure, it enhances the safety of the vehicle during driving.

[0004] This invention is achieved through the following technical solutions:

[0005] A method for intelligent torque distribution control of a three-motor system in a commercial vehicle includes the following steps:

[0006] The first step is to identify the actual operating conditions of the vehicle and design four vehicle operating conditions and drive type allocation and minimum motor operating number control methods, including climbing, getting out of trouble, acceleration, and normal driving. The vehicle operating condition identification method is as follows:

[0007] If the accelerator pedal opening is ≥50% and the vehicle speed is ≤20km / h, it is determined to be a climbing condition, and the drive mode is assigned as 6×4, with a minimum of 3 motors working.

[0008] If the accelerator pedal opening is ≥40% and the difference between the highest wheel speed of the drive axle and the wheel speed of the non-drive axle is ≥200rpm / min, it is determined to be a traction condition. The drive configuration is assigned as 6×4 and the minimum number of motors is 2.

[0009] If the vehicle speed is ≥40km / h and the accelerator pedal opening is ≥50%, it is determined to be an acceleration condition, and the drive mode is assigned as 6×2, with a minimum of 2 motors operating.

[0010] If the climbing, getting out of trouble and acceleration conditions are not identified, it is determined to be a normal driving condition, the drive mode is assigned as 6×2, and the minimum number of motors working is 1;

[0011] The second step is to update the minimum number of motors to be operated. By querying the external characteristic curve of the motor, the upper limit value of the motor output torque is obtained. The upper limit value of the motor output torque is divided by the required torque to obtain a coefficient plus 1, which is the updated value of the minimum number of motors to be operated.

[0012] The third step is to calculate the motor efficiency value of the required torque, design a method for allocating the high-efficiency range of the motor, and obtain the efficiency value corresponding to the input required torque by querying the motor system drive efficiency MAP table. The motor drive efficiency values ​​of 1 times the required torque, 1 / 2 times the required torque, and 1 / 3 times the required torque are obtained respectively.

[0013] The fourth step is to determine the actual number of motors in operation. The motor drive efficiency values ​​of 1 times the required torque, 1 / 2 times the required torque, and 1 / 3 times the required torque are compared respectively. The torque allocation scheme with the highest motor drive efficiency value is selected as the minimum number of motors in operation 1, 2, and 3, respectively. The maximum value between the result and the updated minimum number of motors in operation is taken as the target number of motors in operation.

[0014] The fifth step is to design the main and auxiliary motor sequence value motor allocation method. There are three main and auxiliary motor sequence values: 123, 231, and 312. The sequence values ​​are switched sequentially by turning on the key. Within one key cycle, the cumulative mileage exceeds 200km and the next main and auxiliary motor sequence value is automatically switched.

[0015] Step 6: Based on the actual number of motors in operation and the sequence values ​​of the main and auxiliary motors, determine the specific working motors to be allocated. The required torque for each motor is the required torque divided by the actual number of motors in operation.

[0016] Step 7: During gear shifting, if one motor reduces torque during gear shifting, another motor is used for torque compensation. The compensation torque satisfies the following condition: compensation torque + actual torque of the shifting motor = required torque value. By compensating for torque during gear shifting, the problem of torque interruption during gear shifting is solved, and the smoothness of gear shifting is improved.

[0017] The eighth step involves using the gear ratio to compensate for the change in transmission ratio after shifting up or down. The specific compensation formula is: target torque value = wheel end torque demand / current gear transmission ratio. By compensating for the torque before and after shifting, the problem of sudden torque change in the output shaft of the gearbox before and after shifting is solved, and the smoothness before and after shifting is improved.

[0018] Furthermore, filtering and slope limiting are applied to the output torque to ensure its smoothness and improve the ride comfort of the vehicle.

[0019] A smart control architecture for torque distribution in a three-motor system for commercial vehicles includes a working condition identification layer, a high-efficiency distribution layer, a lifespan management layer, and a smoothness control layer. The working condition identification layer determines whether the vehicle's drive mode is 6×2 or 6×4 based on actual working conditions to ensure that the actual usage requirements of high-horsepower commercial vehicles are met. The high-efficiency distribution layer determines the minimum number of motors operating and the torque distribution scheme for each motor. The lifespan management layer determines which motors to operate and the torque distribution value for each motor through a lifespan allocation algorithm. The smoothness control layer improves the smoothness of vehicle operation by compensating for torque during and after gear shifting, as well as smoothing the output torque and limiting the slope.

[0020] This invention meets the high-load usage requirements of vehicles such as heavy-duty and off-road vehicles by accurately identifying operating conditions. At the same time, it improves the output efficiency of the three-motor system and reduces the energy consumption of vehicle operation by utilizing the high-efficiency range of the motor. By allocating the service life of each motor, it improves the operating life of the three-motor system. It fully considers the unexpected factors of motor failure and integrates motor failure into the intelligent torque distribution control of the three-motor system, thereby improving the safety and reliability of the system. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a three-motor system for a 6x4 commercial vehicle.

[0022] Figure 2 It is a three-motor system intelligent torque distribution control architecture;

[0023] Figure 3 The upper limit of the motor output torque is calculated by looking up a table;

[0024] Figure 4 The required torque motor efficiency value is calculated by looking up a table. Detailed Implementation

[0025] This invention designs an intelligent control architecture for torque distribution in a three-motor system for commercial vehicles, comprising four torque distribution layers. The first layer is the operating condition identification layer, which determines whether the vehicle's drive mode is 6×2 or 6×4 based on actual operating conditions to ensure that the actual usage requirements of high-horsepower commercial vehicles are met. The second layer is the motor high-efficiency range allocation layer, which determines the minimum number of motors operating and the torque distribution scheme for each motor. The third layer is the lifespan management layer, which determines which motors to operate and their torque distribution values ​​through a lifespan allocation algorithm. The fourth layer is the smoothness control layer, which improves the smoothness of vehicle operation by compensating for torque during and after gear shifting, as well as smoothing and limiting the slope of the output torque. Figure 2As shown.

[0026] The three-motor system architecture is based on a 6×4 vehicle where one drive axle has a single motor drive and the other drive axle has a dual-motor parallel drive. For this architecture, the intelligent torque distribution control architecture for the three-motor system in commercial vehicles is as follows: Figure 1 , 2 As shown.

[0027] The intelligent control method for torque distribution in a three-motor system is as follows:

[0028] The first step is to identify the actual operating conditions of the vehicle. This invention designs four vehicle operating conditions and drive mode allocation methods and a minimum number of motors operating control methods, including hill climbing, getting out of trouble, acceleration, and normal driving. The vehicle operating condition identification method is as follows:

[0029] If the accelerator pedal opening is ≥50% (actual vehicle calibration) and the vehicle speed is ≤20km / h (actual vehicle calibration), it is determined to be a climbing condition, and the drive mode is assigned as 6×4, with a minimum of 3 motors operating.

[0030] If the accelerator pedal opening is ≥40% (actual vehicle calibration) and the difference between the highest wheel speed of the drive axle and the wheel speed of the non-drive axle is ≥200rpm / min (actual vehicle calibration), it is determined to be a traction condition, the drive configuration is 6×4, and the minimum number of motors is 2.

[0031] If a vehicle speed ≥ 40km / h (actual vehicle calibration) and accelerator pedal opening ≥ 50% (actual vehicle calibration) are detected, it is determined to be an acceleration condition, and the drive mode is assigned as 6×2, with a minimum of 2 motors operating.

[0032] If climbing, getting out of trouble, and acceleration conditions are not detected, it is determined to be a normal driving condition, and the drive configuration is assigned as 6×2 with a minimum of 1 motor operating.

[0033] The second step is to update the minimum number of motor operations. This is done by querying the motor's external characteristic curve (derived from motor test data; the input value is the motor speed, and the output value is the upper limit of the motor's output torque). The upper limit of the motor's output torque is then obtained by dividing the required torque by the upper limit of the motor's output torque, and the coefficient is added by 1 to get the updated minimum number of motor operations. See [link to documentation]. Figure 3 .

[0034] The third step involves calculating the required torque motor efficiency value. This invention employs a method for allocating the high-efficiency range of the motor. By querying the motor system drive efficiency MAP table (derived from motor test data, the MAP table has two input values: motor speed and torque, and the output value is the motor drive efficiency value), the efficiency value corresponding to the input required torque is obtained. Specifically, the motor drive efficiency values ​​for 1x, 1 / 2x, and 1 / 3x the required torque are retrieved. See [link / see details]. Figure 4 .

[0035] The fourth step is to determine the actual number of motors in operation. The driving efficiency values ​​for motors operating at 1 times the required torque, 1 / 2 times the required torque, and 1 / 3 times the required torque are compared. The torque allocation scheme with the highest driving efficiency value is selected, designated as minimum motor operating number 1, minimum motor operating number 2, and minimum motor operating number 3, respectively. The maximum value between this result and the updated minimum motor operating number is taken as the target number of motors in operation. The actual number of motors in operation is obtained by subtracting the number of faulty motors from the target number of motors in operation.

[0036] Fifth, this invention designs a main and auxiliary motor sequence value motor allocation method. The main and auxiliary motor sequence values ​​are divided into three types, namely 123, 231, and 312. By turning on the key, the sequence values ​​123, 231, and 312 are switched in sequence. Within one key cycle, if the cumulative mileage exceeds 200km (test data calibration), the next main and auxiliary motor sequence value needs to be automatically switched.

[0037] Step 6: Based on the actual number of motors in operation and the sequence value of the main and auxiliary motors, determine the specific working motors to be assigned. The required torque of each motor is the required torque divided by the actual number of motors in operation. For example, if the actual number of motors in operation is 2 and the sequence value of the main and auxiliary motors is 231, then the working motors are motor 2 and motor 3.

[0038] The seventh step involves addressing the torque reduction issue during gear shifting. If one motor reduces torque during shifting, another motor is needed for torque compensation. The compensation torque must satisfy the following condition: compensation torque + actual torque of the shifting motor = required torque value. By compensating for torque during gear shifting, the torque interruption problem during shifting is resolved, improving the smoothness of gear shifting.

[0039] The eighth step involves addressing the change in transmission ratio after shifting gears. Torque compensation using this ratio is necessary. The specific formula is: Target torque value = Wheel-end torque requirement / Current gear transmission ratio. For example, in a four-speed transmission, the corresponding gear ratios for 1st / 2nd / 3rd / 4th gears are 8.482 / 4.265 / 2.019 / 1, respectively. Therefore, the corresponding torque values ​​for the transmission output shaft T in each gear are: 1st gear: T / 8.482, 2nd gear: T / 4.265, 3rd gear: T / 2.019, and 4th gear: T / 1. By compensating for torque before and after gear shifts, the problem of sudden changes in transmission output shaft torque before and after shifts is solved, improving smoothness. Finally, filtering and slope limiting are applied to the output torque to ensure smoothness and further improve vehicle ride comfort.

[0040] This invention designs an intelligent control method for torque distribution in a three-motor system, including a method for identifying the actual operating conditions of the vehicle, a torque distribution control method that makes full use of the high-efficiency range of the motors, a method for allocating the service life of each motor in the three-motor system, and also fully considers the control of motor torque distribution in the event of motor failure, thus making the intelligent control method for torque distribution in a three-motor system highly robust.

Claims

1. A method for intelligent control of torque distribution in a three-motor system for commercial vehicles, characterized by: Includes the following steps: The first step is to identify the actual operating conditions of the vehicle and design four vehicle operating conditions and drive type allocation and minimum motor operating number control methods, including climbing, getting out of trouble, acceleration, and normal driving. The vehicle operating condition identification method is as follows: If the accelerator pedal opening is ≥50% and the vehicle speed is ≤20km / h, it is determined to be a climbing condition, and the drive mode is assigned as 6×4, with a minimum of 3 motors working. If the accelerator pedal opening is ≥40% and the difference between the highest wheel speed of the drive axle and the wheel speed of the non-drive axle is ≥200rpm / min, it is determined to be a traction condition. The drive configuration is assigned as 6×4 and the minimum number of motors is 2. If the vehicle speed is ≥40km / h and the accelerator pedal opening is ≥50%, it is determined to be an acceleration condition, and the drive mode is assigned as 6×2, with a minimum of 2 motors operating. If the climbing, getting out of trouble and acceleration conditions are not identified, it is determined to be a normal driving condition, the drive mode is assigned as 6×2, and the minimum number of motors working is 1; The second step is to update the minimum number of motors to be operated. By querying the external characteristic curve of the motor, the upper limit value of the motor output torque is obtained. The upper limit value of the motor output torque is divided by the required torque to obtain a coefficient plus 1, which is the updated value of the minimum number of motors to be operated. The third step is to calculate the motor efficiency value of the required torque, design a method for allocating the high-efficiency range of the motor, and obtain the efficiency value corresponding to the input required torque by querying the motor system drive efficiency MAP table. The motor drive efficiency values ​​of 1 times the required torque, 1 / 2 times the required torque, and 1 / 3 times the required torque are obtained respectively. The fourth step is to determine the actual number of motors in operation. The motor drive efficiency values ​​of 1 times the required torque, 1 / 2 times the required torque, and 1 / 3 times the required torque are compared respectively. The torque allocation scheme with the highest motor drive efficiency value is selected as the minimum number of motors in operation 1, 2, and 3, respectively. The maximum value between the result and the updated minimum number of motors in operation is taken as the target number of motors in operation. The fifth step is to design the main and auxiliary motor sequence value motor allocation method. There are three main and auxiliary motor sequence values: 123, 231, and 312. The sequence values ​​are switched sequentially by turning on the key. Within one key cycle, the cumulative mileage exceeds 200km and the next main and auxiliary motor sequence value is automatically switched. Step 6: Based on the actual number of motors in operation and the sequence values ​​of the main and auxiliary motors, determine the specific working motors to be allocated. The required torque for each motor is the required torque divided by the actual number of motors in operation. Step 7: During gear shifting, if one motor reduces torque during gear shifting, another motor is used for torque compensation. The compensation torque satisfies the following condition: compensation torque + actual torque of the shifting motor = required torque value. By compensating for torque during gear shifting, the problem of torque interruption during gear shifting is solved, and the smoothness of gear shifting is improved. The eighth step involves using the gear ratio to compensate for the change in transmission ratio after shifting up or down. The specific compensation formula is: target torque value = wheel end torque demand / current gear transmission ratio. By compensating for the torque before and after shifting, the problem of sudden torque change in the output shaft of the gearbox before and after shifting is solved, and the smoothness before and after shifting is improved.

2. The intelligent control method for torque distribution in a three-motor system of a commercial vehicle according to claim 1, characterized in that: The output torque is filtered and the slope is limited to ensure smooth output torque and improve the smoothness of vehicle operation.

3. A smart control architecture for torque distribution in a three-motor system for commercial vehicles, characterized by: It includes a working condition identification layer, an efficient allocation layer, a lifespan management layer, and a smoothness control layer. The working condition identification layer determines whether the vehicle drive mode is 6×2 or 6×4 based on the actual working conditions to ensure that it meets the actual usage requirements of high-horsepower commercial vehicles. The efficient allocation layer determines the minimum number of motors to operate and the torque distribution scheme of each motor. The lifespan management layer determines which motors to operate and the torque distribution value of each motor through the lifespan allocation algorithm of each motor. The smoothness control layer improves the smoothness of vehicle operation by compensating for torque during and after shifting gears, as well as smoothing the output torque and limiting the slope.

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