A control method and device of a three-motor hybrid vehicle, a vehicle and a medium

Abstract

The application discloses a control method and device of a three-motor hybrid vehicle, the vehicle and a medium, and the method comprises the following steps: when the vehicle is in an engine direct-drive four-wheel drive power generation mode, determining a power battery target power based on front drive motor demand power, rear drive motor demand power and accessory power; acquiring power battery actual power and power battery charging / discharging capacity; determining a power battery target feedback control result; determining front drive motor feedback control demand power; determining front drive motor feedback control demand torque; adjusting the output torque of the front drive motor based on the front drive motor feedback control demand torque, and returning to the step of acquiring the power battery actual power and the power battery charging / discharging capacity. The control method of the three-motor hybrid vehicle provided by the application can control the actual power of the battery to quickly reach the target power by adjusting the output torque of the front drive motor.

Description

Technical Field

[0001] This invention relates to the field of vehicle control technology, and in particular to a control method, device, vehicle, and medium for a three-motor hybrid vehicle. Background Technology

[0002] To address global demands for CO2 emission reduction, a three-motor hybrid vehicle has been developed. This vehicle can operate in three modes: pure electric mode, series mode, and engine direct drive mode, automatically switching modes based on driving conditions to achieve better overall vehicle fuel economy. The three-motor hybrid powertrain mainly consists of an engine, a generator, and front and rear drive motors.

[0003] In a hybrid vehicle with a three-motor structure, the vehicle enters a series operating mode after the engine starts. In this mode, the engine drives a generator to produce electricity to power the front and rear axle drive motors and the battery, or the engine-driven generator, along with the battery, powers both the front and rear drive motors. As the vehicle speed increases, when the driver's load and speed reach the engine-driven direct drive economic zone, the clutch engages, and the engine directly participates in driving, entering engine-driven direct drive mode. In engine-driven direct drive two-wheel drive mode, the rear axle drive motor torque is zero, and the engine and front axle drive motor work together to drive the vehicle. In engine-driven direct drive four-wheel drive mode, the engine, front and rear axle drive motors work together to drive the vehicle.

[0004] However, when a hybrid vehicle is in engine-driven four-wheel drive power generation mode, with the front axle engine driving the front axle drive motor to generate electricity and the rear axle drive motor outputting positive torque, part of the engine's output power is used to drive the vehicle, and part is used to provide electricity for the rear axle drive motor's driving torque and to charge the battery. At this time, the front drive motor is in a power generation state, with part of the generated power meeting the needs of the rear drive motor and part charging the battery. Due to the efficiency of the front and rear drive motors and the efficiency of mechanical energy conversion to electrical energy, the battery charge may not reach the target value for a long time, or may even deviate from the target value. Summary of the Invention

[0005] This invention provides a control method, device, vehicle, and medium for a three-motor hybrid vehicle, which achieves the effect of rapidly controlling the actual power of the battery to reach the target power by adjusting the output torque of the front drive motor.

[0006] In a first aspect, the present invention provides a control method for a three-motor hybrid vehicle, comprising:

[0007] When the vehicle is in engine direct drive four-wheel drive power generation mode, the target power of the power battery is determined based on the power demand of the front drive motor, the power demand of the rear drive motor, and the power of the accessories.

[0008] To obtain the actual power of the power battery and its charging / discharging capacity;

[0009] The target feedback control result of the power battery is determined based on the target power of the power battery, the actual power of the power battery, and the charging / discharging capacity of the power battery.

[0010] Based on the target feedback control result of the power battery, the required power of the rear drive motor, and the power of the accessory, the required power of the front drive motor feedback control is determined.

[0011] The feedback control torque of the front drive motor is determined based on the power required for the front drive motor feedback control.

[0012] Based on the feedback control torque requirement of the front drive motor, adjust the output torque of the front drive motor, and return to the execution of the steps to obtain the actual power of the power battery and the charging / discharging capacity of the power battery.

[0013] In a second aspect, the present invention provides a control device for a three-motor hybrid vehicle, comprising:

[0014] The battery target power determination module is used to determine the target power of the power battery based on the power demand of the front drive motor, the power demand of the rear drive motor, and the power of the accessories when the vehicle is in the engine direct drive four-wheel drive power generation mode.

[0015] The battery capability acquisition module is used to acquire the actual power of the power battery and its charging / discharging capability.

[0016] The battery feedback result determination module is used to determine the target feedback control result of the power battery based on the target power of the power battery, the actual power of the power battery, and the charging / discharging capacity of the power battery.

[0017] The front drive motor feedback demand power determination module is used to determine the front drive motor feedback control demand power based on the target feedback control result of the power battery, the demand power of the rear drive motor, and the power of the accessory.

[0018] The front drive motor feedback demand torque determination module determines the front drive motor feedback control demand torque based on the front drive motor feedback control demand power.

[0019] The front drive motor torque adjustment module is used to adjust the output torque of the front drive motor based on the feedback control torque demand of the front drive motor, and return to the execution steps of obtaining the actual power of the power battery and the charging / discharging capacity of the power battery.

[0020] Thirdly, the present invention provides a vehicle, comprising: an engine, an engine management system, a generator, a generator control unit, a generator inverter, a front drive motor, a front drive motor control unit, a front drive motor inverter, a front axle reduction gear, a front axle wheel, a rear drive motor, a rear drive motor control unit, a rear drive motor inverter, a rear axle reduction gear, a rear axle wheel, a power battery, a battery management system, a clutch, and a vehicle controller.

[0021] The engine management system is electrically connected to the engine;

[0022] The generator is electrically connected to the power battery via the generator inverter; the generator control unit is electrically connected to the generator via the generator inverter.

[0023] The front drive motor is electrically connected to the engine and the power battery respectively through the front drive motor inverter; the front drive motor control unit is electrically connected to the front drive motor through the front drive motor inverter; the front drive motor is mechanically connected to the front axle wheel through the front axle reduction device.

[0024] The rear drive motor is electrically connected to the engine via the rear drive motor inverter; the rear drive motor control unit is electrically connected to the rear drive motor via the rear drive motor inverter; the rear drive motor is mechanically connected to the rear axle wheels via the rear axle reduction gear.

[0025] The battery management system is electrically connected to the power battery; the engine is linked to the generator via a gear pair, and the engine is also mechanically connected to the front axle reduction gear via the clutch;

[0026] The vehicle controller is communicatively connected to the engine management system, the front drive motor control unit, the rear drive motor control unit, the generator control unit, and the battery management system, respectively; the vehicle controller is used to execute the control method for the three-motor hybrid vehicle described in the first aspect of the present invention.

[0027] Fourthly, the present invention provides a computer-readable storage medium storing computer instructions that, when executed by a processor, implement the control method for a three-motor hybrid vehicle described in the first aspect of the present invention.

[0028] The technical solution provided by this invention, when the vehicle is in engine direct drive four-wheel drive power generation mode, firstly, determines the target power of the power battery based on the acquired power requirements of the front drive motor, the rear drive motor, and the accessory power; secondly, acquires the actual power of the power battery and its charging / discharging capacity; and based on the target power of the power battery, its actual power, and its charging / discharging capacity, determines the target feedback control result of the power battery; thirdly, based on the target feedback control result of the power battery, the power requirements of the rear drive motor, and the accessory power, determines the feedback control power requirement of the front drive motor, and further determines the feedback control torque requirement of the front drive motor; and finally, based on the feedback control torque requirement of the front drive motor, adjusts the output torque of the front drive motor, and returns to acquire the actual power of the power battery and its charging / discharging capacity to further determine whether to adjust the actual power of the power battery, thereby achieving the effect of quickly controlling the actual power of the battery to reach the target power. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of a vehicle structure provided in Embodiment 1 of the present invention;

[0030] Figure 2 This is a flowchart of a control method for a three-motor hybrid vehicle provided in Embodiment 2 of the present invention;

[0031] Figure 3 A flowchart of a control method for a three-motor hybrid vehicle provided in Embodiment 3 of the present invention;

[0032] Figure 4 This is a flowchart of a control method for a three-motor hybrid vehicle provided in Embodiment 4 of the present invention;

[0033] Figure 5 A flowchart of a control method for a three-motor hybrid vehicle provided in Embodiment 5 of the present invention;

[0034] Figure 6 A flowchart of a control method for a three-motor hybrid vehicle provided in Embodiment Six of the present invention;

[0035] Figure 7 A flowchart of a control method for a three-motor hybrid vehicle provided in Embodiment 7 of the present invention;

[0036] Figure 8 A flowchart of a control method for a three-motor hybrid vehicle provided in Embodiment 8 of the present invention;

[0037] Figure 9 A flowchart of a control method for a three-motor hybrid vehicle provided in Embodiment 9 of the present invention;

[0038] Figure 10 This is a schematic diagram of a control device for a three-motor hybrid vehicle provided in Embodiment 10 of the present invention. Detailed Implementation

[0039] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0040] Example 1

[0041] Figure 1 This is a schematic diagram of a vehicle structure provided in Embodiment 1 of the present invention, as shown below. Figure 1 As shown, the vehicle includes: an engine 101, an engine management system 102, a generator 103, a generator control unit 104, a generator inverter 105, a front drive motor 106, a front drive motor control unit 107, a front drive motor inverter 108, a front axle reduction gear 109, a front axle wheel 110, a rear drive motor 111, a rear drive motor control unit 112, a rear drive motor inverter 113, a rear axle reduction gear 114, a rear axle wheel 115, a power battery 116, a battery management system 117, a clutch 118, and a vehicle controller 119.

[0042] The engine management system 102 is electrically connected to the engine 101; the engine management system 102 is used to control operations such as fuel cut-off shutdown or fuel injection ignition of the engine 101. The generator 103 is electrically connected to the power battery 116 via a generator inverter 105; the generator control unit 104 is electrically connected to the generator 103 via the generator inverter 105; the generator inverter 105 ensures that the generator 103 can charge the power battery 116, or that the power battery 116 can provide power to the generator 103. The generator inverter 105 enables the generator 103 to receive control signals from the generator control unit 104 and perform corresponding operations. The front drive motor 106 is electrically connected to the engine 101 and the power battery 116 via the front drive motor inverter 108; the front drive motor control unit 107 is electrically connected to the front drive motor 106 via the front drive motor inverter 108; the front drive motor 106 is mechanically connected to the front axle wheel 110 via the front axle reduction gear 109; the rear drive motor 111 is electrically connected to the engine 101 via the rear drive motor inverter 113; the rear drive motor control unit 112 is electrically connected to the rear drive motor 111 via the rear drive motor inverter 113; the rear drive motor 111 is electrically connected to the rear axle reduction gear... The rear axle wheel 115 is mechanically connected to the rear axle wheel 115; the battery management system 117 is electrically connected to the power battery 116; the engine 101 and the generator 103 are linked through a gear pair, and the engine 101 is also mechanically connected to the front axle reduction gear 109 through the clutch 118; the vehicle controller 119 is communicatively connected to the engine management system 102, the front drive motor control unit 107, the rear drive motor control unit 112, the generator control unit 104, and the battery management system 117 respectively; the vehicle controller 119 is used to execute the control method of the three-motor hybrid vehicle of any embodiment of the present invention.

[0043] Specifically, the electrical connection between the front drive motor inverter 108 and the front drive motor 106, the engine 101, and the power battery 116 ensures that the energy provided by the engine 101 and the power battery 116 can be transferred to the front drive motor 106. The electrical connection between the front drive motor inverter 108 and the front drive motor control unit 107 and the front drive motor 106 ensures that the control signals issued by the front drive motor control unit 107 can be received by the front drive motor 106 and corresponding actions can be taken. The front drive motor control unit 107 is used to report parameters such as the torque or vehicle speed of the front drive motor 106. The mechanical connection between the front axle reduction gear 109 and the front drive motor 106 and the front axle wheels 110 allows the front drive motor 106 to perform operations such as deceleration or torque recovery on the front axle wheels 110 through the front axle reduction gear 109.

[0044] The electrical connection between the rear drive motor inverter 113, the rear drive motor 111, and the engine 101 ensures that the energy provided by the engine 101 can be transferred to the rear drive motor 111. The electrical connection between the rear drive motor inverter 113, the rear drive motor control unit 112, and the rear drive motor 111 ensures that the control signals issued by the rear drive motor control unit 112 can be received by the rear drive motor 111 and corresponding actions can be performed. The rear drive motor control unit 112 is also used to report parameters such as the torque or vehicle speed of the rear drive motor 111. The mechanical connection between the rear axle reduction gear 114, the rear drive motor 111, and the rear axle wheels 115 allows the rear drive motor 111 to perform operations such as deceleration or torque recovery on the rear axle wheels 115 through the rear axle reduction gear 114.

[0045] The battery management system 117 is used to report the actual voltage and current of the power battery 116, as well as parameters such as battery charge, temperature, and health status. The generator 103 can start the engine 101 through gears. When the clutch 118 is disengaged, the engine 101 does not directly drive the vehicle, but instead drives the generator 103 to generate electricity, providing energy to the battery 116 or the drive motor, which then drives the vehicle. When the clutch 118 is engaged, the torque of the engine 101 is transmitted to the wheels through the clutch 118 and the reduction gear, allowing the engine 101 to work with the front and rear drive motors to drive the hybrid vehicle.

[0046] The vehicle controller 119 is used to receive signals transmitted from the engine management system 102, the front drive motor control unit 107, the rear drive motor control unit 112, the generator control unit 104, and the battery management system 117, and sends fuel injection commands and related torque commands according to these signals to the corresponding execution units or systems.

[0047] The vehicle provided in the embodiments of the present invention is used to execute the control method of the three-motor hybrid vehicle provided in any embodiment of the present invention, and has the same beneficial effect, that is, by controlling the output torque of the engine and the front drive motor, the actual power of the power battery can reach the target power as soon as possible.

[0048] Example 2

[0049] Figure 2 This is a flowchart of a control method for a three-motor hybrid vehicle provided in Embodiment 2 of the present invention. This method is applicable when the battery charge in the vehicle deviates from a target value. This method can be executed by the control device of the three-motor hybrid vehicle provided in this embodiment of the invention, which is implemented in hardware and / or software. Figure 2 As shown, the control method for this three-motor hybrid vehicle includes:

[0050] S210. When the vehicle is in engine direct drive four-wheel drive power generation mode, the target power of the power battery is determined based on the power demand of the front drive motor, the power demand of the rear drive motor, and the power of the accessories.

[0051] In the engine-driven four-wheel drive power generation mode, the engine and the front and rear axle drive motors work together to drive the vehicle. The power requirements of the front drive motor, rear drive motor, and accessories are calculated using their respective formulas after the corresponding control units report relevant parameters. The target power of the power battery can be determined by the power requirements of the front drive motor, rear drive motor, and accessories.

[0052] Optionally, the target power of the power battery is determined based on the required power of the front drive motor, the required power of the rear drive motor, and the power of the accessories. Specifically, a formula for calculating the target power of the battery is constructed based on the required power of the front drive motor, the required power of the rear drive motor, and the power of the accessories; the target power of the battery is calculated using the formula for calculating the target power of the battery.

[0053] The formula for calculating the target battery power is: Target battery power = (Power required by the front drive motor + Power required by the rear drive motor + Power of accessories) * (-1).

[0054] Specifically, the required torque of the front drive motor = the sum of the required torques of the front and rear drive motors - the required torque of the rear axle in the four-wheel drive torque distribution. The required power of the front drive motor = the required torque of the front drive motor * the front drive motor speed / the final drive ratio / 9550. Here, the required torque and speed of the front drive motor are reported by the front drive motor control unit, the final drive ratio is a preset fixed value, and 9550 is an empirical value. The required torque and speed of the rear drive motor are reported by the rear drive motor control unit. The required power of the rear drive motor = the required torque of the rear drive motor * the rear drive motor speed / the final drive ratio / 9550. The accessory power is the sum of the required power of the high-voltage or low-voltage equipment in the vehicle. After determining the required power of the front drive motor, the required power of the rear drive motor, and the accessory power, the target battery power can be calculated based on the above battery target power calculation formula. During charging, the target battery power is defined as positive, and during discharging, the target battery power is defined as negative.

[0055] S220: Obtain the actual power of the power battery and the charging / discharging capability of the power battery.

[0056] Specifically, the actual voltage, actual current, and charge / discharge capacity of the power battery are reported by the battery management system. Based on the reported actual voltage of the power battery, the actual power of the power battery is calculated as: Actual voltage of power battery * Actual current of power battery / 1000 * (-1) (unit: kilowatt). Similarly, the actual power of the power battery is defined as positive when charging and negative when discharging.

[0057] S230. Determine the target feedback control result of the power battery based on the target power of the power battery, the actual power of the power battery, and the charging / discharging capacity of the power battery.

[0058] Specifically, the target feedback control result for the power battery is calculated as follows: Max(Min(Power battery discharge capacity (positive), Power battery target power + Power battery power error integral), Power battery charging capacity (negative)). Here, the difference between the target power and the actual power of the power battery is the target power feedback error, and the power error integral is determined by parameters such as the target power feedback error and the power feedback error. The purpose of calculating the target feedback control result is to limit the sum of the target power and the integral portion of the target power feedback to between the power battery discharge capacity and the power battery charging capacity, or between the maximum and minimum values. When the sum of the target power and the integral portion of the target power feedback is greater than the charging capacity but less than the discharge capacity, the sum of the target power and the integral portion of the target power feedback is the target feedback control result.

[0059] S240. Based on the target feedback control results of the power battery, the required power of the rear drive motor and the power of the accessories, determine the required power of the front drive motor feedback control.

[0060] Among them, the power demand for feedback control of the front drive motor = the target feedback control result of the power battery + the power demand for the rear drive motor + the power of the accessories.

[0061] S250. Determine the feedback control torque requirement of the front drive motor based on the power requirement of the front drive motor feedback control.

[0062] The torque required for feedback control of the front drive motor can be determined based on the power required for feedback control of the front drive motor, that is, it can be calculated using the formula for the power required for feedback control of the front drive motor.

[0063] Optionally, the feedback control required torque of the front drive motor is determined based on the feedback control required power of the front drive motor, including: obtaining the front drive motor speed and the main reduction ratio; constructing a calculation formula for the feedback control required torque of the front drive motor based on the front drive motor speed, the main reduction ratio, and the feedback control required power of the front drive motor; the calculation formula for the feedback control required torque of the front drive motor is: feedback control required torque of the front drive motor = feedback control required power of the front drive motor * 9550 / front drive motor speed * main reduction ratio * (-1); the feedback control required torque of the front drive motor is determined based on the calculation formula.

[0064] Specifically, the front drive motor speed is reported by the battery management system, and the main reduction ratio is a preset fixed value. Based on the obtained front drive motor speed, main reduction ratio, and front drive motor feedback control power requirement, the front drive motor feedback control torque requirement can be calculated using the formula for calculating the front drive motor feedback control torque requirement.

[0065] S260: Based on the feedback control torque demand of the front drive motor, adjust the output torque of the front drive motor and return to execute S220.

[0066] Specifically, based on the obtained feedback control torque requirement of the front drive motor, the output torque of the front drive motor is adjusted, and the process returns to obtain the actual power and charging / discharging capacity of the power battery. If the actual power of the power battery is equal to the target power, there is no need to further determine the target feedback control result. If there is still a gap between the actual power and the target power, the target feedback control result is determined, and then the feedback control torque requirement of the front drive motor is determined. By adjusting the output torque of the front drive motor, the actual power of the power battery is made equal to the target power. This process is repeated until the actual power of the power battery equals the target power.

[0067] The control method for a three-motor hybrid vehicle provided in this invention, when the vehicle is in engine direct drive four-wheel drive power generation mode, firstly, determines the target power of the power battery based on the acquired power demand of the front drive motor, the power demand of the rear drive motor, and the accessory power. Secondly, it acquires the actual power of the power battery and the power battery charging / discharging capacity, and determines the target feedback control result of the power battery based on the target power of the power battery, the actual power of the power battery, and the power battery charging / discharging capacity. Thirdly, based on the target feedback control result of the power battery, the power demand of the rear drive motor, and the accessory power, it determines the feedback control demand power of the front drive motor, and then determines the feedback control demand torque of the front drive motor. Further, based on the feedback control demand torque of the front drive motor, it adjusts the output torque of the front drive motor, and then returns to acquire the actual power of the power battery and the power battery charging / discharging capacity to continue to determine whether to adjust the actual power of the power battery, thereby achieving the effect of quickly controlling the actual power of the battery to reach the target power.

[0068] Example 3

[0069] Figure 3 This is a flowchart of a control method for a three-motor hybrid vehicle provided in Embodiment 3 of the present invention. Based on the above embodiments, this embodiment describes how the target feedback control result of the power battery is determined according to the target power of the power battery, the actual power of the power battery, and the charging / discharging capacity of the power battery. For example... Figure 3 As shown, the method includes:

[0070] S301. When the vehicle is in engine direct drive four-wheel drive power generation mode, the target power of the power battery is determined based on the power demand of the front drive motor, the power demand of the rear drive motor, and the power of the accessories.

[0071] S302, Obtain the actual power of the power battery and the charging / discharging capability of the power battery.

[0072] S303. Determine the power battery power feedback error based on the difference between the target power of the power battery and the actual power of the power battery.

[0073] Among them, the power battery power feedback error = power battery target power - power battery actual power.

[0074] S304. Determine whether the power battery power feedback error is less than the preset power error value; if so, proceed to S305.

[0075] The preset power error value is a pre-set fixed value, which is a relatively small value.

[0076] Specifically, if the power battery power feedback error is less than the difference, the integral gain coefficient is determined based on the power battery power feedback error. If the power battery power feedback error is greater than or equal to the difference, it indicates that the difference between the actual power of the power battery and the target power is too large, and the subsequent steps are not used to adjust the actual power of the power battery.

[0077] S305. Determine the integral gain coefficient based on the power battery power feedback error.

[0078] Specifically, if the power battery power feedback error is less than the preset power error value, it indicates that the difference between the actual power and the target power of the power battery is very small. In this case, the present invention uses an integral method to adjust the actual power of the power battery, requiring the determination of the integral gain coefficient. The integral gain coefficient consists of two parts: the integral coefficient and the gain coefficient, determined by the product of the integral coefficient and the gain coefficient. The gain coefficient is obtained using a one-dimensional lookup table of the power battery power feedback error, and the integral coefficient can be 1 or 0. Specifically, when the actual power of the power battery is in the same direction as the target power of the power battery and the difference is within a certain range, and within the power battery's capability range, the gain coefficient is set to 1; otherwise, it is 0, to reduce the fluctuation of the feedback control target caused by the engine operating point fluctuation during speed adjustment. When the gain coefficient is 0, the integral gain coefficient is not directly cleared to zero. Instead, after a certain delay time, if the gain system remains at 0, the integral gain coefficient is cleared to zero to prevent repeated jumps in the direction of the actual power and the target power of the power battery. During the delay time, the power battery power feedback error remains unchanged, while the integral calculation is paused when the integral gain coefficient is 0, thereby achieving the control target and preventing fluctuations in the integral part of the target power feedback of the series drive battery.

[0079] S306. The integral of the product of the power battery power feedback error and the integral gain coefficient over time is determined as the power battery power error integral quantity.

[0080] Specifically, after determining the integral gain coefficient, the product of the power battery power feedback error and the integral gain coefficient can be integrated over time to obtain the power battery power error integral quantity. This power battery power error integral quantity ensures that the deviation between the target power and the actual power of the battery is adjusted within a certain range. Correspondingly, when the power battery power feedback error exceeds a certain range, i.e., when the power battery power feedback error is greater than or equal to the preset power error value, it can be considered that a steady-state operating condition has not been reached or that there is a large deviation in the response accuracy of the vehicle assembly. In this case, the product of the power battery power feedback error and the integral gain system will not be integrated over time, and other methods can be used for adjustment.

[0081] S307. Determine the target feedback control result of the power battery based on the integral of the power battery power error, the target power of the power battery, and the charging / discharging capacity of the power battery.

[0082] Specifically, the sum of the power battery power error integral and the power battery target power should satisfy the power battery's charging / discharging capacity. In this case, the power battery charging capacity can be used as the upper limit and the power battery discharging capacity as the lower limit to restrict the sum of the power battery power error integral and the power battery target power. That is, the power battery target feedback control result = Max(Min(power battery discharging capacity (positive), power battery target power + power battery power error integral), power battery charging capacity (negative)). When the sum of the power battery target power and the power battery power error integral is between the power battery discharging capacity and the power battery charging capacity, the sum of the power battery target power and the power battery power error integral can be directly determined as the power battery target feedback control result.

[0083] Furthermore, in determining the integral amount of the power battery power error by integrating the product of the power battery feedback error and the integral gain coefficient over time, the slope of the change of the integral amount of the power battery power error can be limited. That is, the integral amount of the power battery power error should not have a large change, so as to ensure that the integral part is smoothly superimposed on the target power of the battery.

[0084] Optionally, based on the integral of the power battery power error, the target power of the power battery, and the charging / discharging capacity of the power battery, the target feedback control result for the power battery is determined, including: determining whether the sum of the integral of the power battery power error and the target power of the power battery is less than the power battery discharge capacity; if so, further determining whether the sum of the integral of the power battery power error and the target power of the power battery is greater than the power battery charging capacity; if so, the sum of the integral of the power battery power error and the target power of the power battery is determined as the target feedback control result for the power battery; if the sum of the integral of the power battery power error and the target power of the power battery is greater than or equal to the power battery discharge capacity, the power battery discharge capacity is determined as the target feedback control result for the power battery; if the sum of the integral of the power battery power error and the target power of the power battery is less than or equal to the power battery charging capacity, the power battery charging capacity is determined as the target feedback control result for the power battery.

[0085] Specifically, both the battery discharge capacity and the battery charging capacity can be reported by the battery management system. After determining the sum of the battery power error integral and the battery target power, this sum is compared with the battery discharge capacity and the battery charging capacity respectively to determine whether it falls within the range between the battery discharge capacity and the battery charging capacity. If the sum of the battery power error integral and the battery target power falls within the range between the battery discharge capacity and the battery charging capacity, that is, the sum of the battery power error integral and the battery target power is greater than the battery charging capacity but less than the battery discharge capacity, then the sum of the battery power error integral and the battery target power can be determined as the battery target feedback control result. Conversely, if the sum of the battery power error integral and the battery target power is less than the battery charging capacity, then the battery charging capacity can be directly determined as the battery target feedback control result. Alternatively, if the sum of the battery power error integral and the battery target power is less than the battery discharge capacity, then the battery discharge capacity can be directly determined as the battery target feedback control result. In this way, by using the charging capacity and discharging capacity of the power battery to limit the target feedback control result of the power battery, the target feedback control result of the power battery changes smoothly and within a reasonable range.

[0086] S308. Based on the target feedback control results of the power battery, the required power of the rear drive motor and the power of the accessories, determine the required power of the front drive motor feedback control.

[0087] S309. Determine the feedback control torque of the front drive motor based on the power required for feedback control of the front drive motor.

[0088] S310: Based on the feedback control torque demand of the front drive motor, adjust the output torque of the front drive motor and return to execute S302.

[0089] The control method for a three-motor hybrid vehicle provided in this invention determines the power battery power feedback error by obtaining the difference between the actual power of the power battery and the target power of the power battery. Then, it determines whether the power battery power feedback error is less than a preset power error value. If so, it determines the integral gain coefficient and the integral amount of the power battery error based on the power battery power feedback error. Furthermore, it determines the target feedback control result of the power battery and the feedback control torque requirement of the front drive motor based on the integral amount of the power battery power error, the target power of the power battery, and the charging / discharging capacity of the power battery. Then, it adjusts the output torque of the front drive motor to enable the actual power of the battery to quickly reach the target power.

[0090] Example 4

[0091] Figure 4 This is a flowchart of a control method for a three-motor hybrid vehicle provided in Embodiment 4 of the present invention. Based on the above embodiments, this method is applicable to situations where the target power of the power battery is determined based on the power requirements of the front drive motor, the rear drive motor, and the accessory power. Figure 4 As shown, the method also includes:

[0092] S401, obtain the driver's required torque, accessory power required torque, power battery charge balance torque, engine actual torque, engine speed, power battery charge information, SOC balance charging torque and SOC balance discharging torque.

[0093] Specifically, the driver's required torque is calculated using a two-dimensional lookup table based on accelerator pedal opening and vehicle speed; the accessory power required torque is determined by parameters such as accessory power, front drive motor efficiency, and engine speed; the power battery charge balance torque is related to parameters such as front drive motor efficiency, power battery status information, current vehicle speed, SOC balance charging power, and SOC balance discharging power; the actual engine torque is reported by the engine management system. Engine speed is also reported by the engine management system; the SOC balance charging power and SOC balance discharging power are calculated using a one-dimensional lookup table based on the difference between the power battery charge level and the median value.

[0094] Optionally, the accessory power demand torque is obtained, including: obtaining the front drive motor efficiency, the power demand of the high-voltage accessory, and the power demand of the low-voltage accessory; determining the accessory power by summing the power demand of the high-voltage accessory and the power demand of the low-voltage accessory; and determining the accessory power demand torque based on the accessory power, engine speed, and front drive motor efficiency.

[0095] Specifically, the efficiency of the front drive motor is obtained by looking up a two-dimensional table using the actual torque and actual speed of the front drive motor. Both the actual torque and actual speed of the front drive motor are reported by the front drive motor control unit. Accessory power includes high-voltage accessory power and low-voltage accessory power, i.e., accessory power = demanded power of high-voltage accessories + demanded power of low-voltage accessories. High-voltage accessory power is reported by the controller of the high-voltage accessories, which may include air conditioning, etc. Low-voltage accessory power is calculated from the voltage and current output by the DC-DC voltage converter, and low-voltage accessories may include entertainment facilities, etc. Engine speed is reported by the engine management system. Correspondingly, the accessory power demand torque = accessory power * 9550 / front drive motor efficiency / engine speed. The obtained accessory power demand torque output needs to be filtered, for example, using a first-order filter, to eliminate glitches.

[0096] Optionally, the power battery charge balancing torque is obtained, including: obtaining the front drive motor efficiency, power battery status information, current vehicle speed information, SOC balance charging power, and SOC balance discharging power; determining the upper limit of power battery charging during driving and the lower limit of power battery assist based on the power battery status information and current vehicle speed information; determining the forced generation power and forced discharge power of the power battery based on the power battery charge information, the upper limit of power battery charging during driving, and the lower limit of power battery assist; determining the power battery charge balancing power based on the SOC balance charging power, SOC balance discharging power, forced generation power, and forced discharge power; and determining the power battery charge balancing torque based on the battery charge balancing power, the front drive motor efficiency, and the engine speed.

[0097] Specifically, the efficiency of the front drive motor is calculated by a two-dimensional lookup table based on the actual torque and actual speed of the front drive motor, both of which are reported by the front drive motor control unit; the power battery status information, including the power battery charge, temperature, and health status, is reported by the battery management system; the current vehicle speed information can be obtained through the corresponding sensors; and the SOC balance charging power and SOC balance discharging power are calculated by a one-dimensional lookup table based on the difference between the power battery charge and the median value.

[0098] The upper limit of the power battery charging limit is set by offsetting a certain value upwards from the median power battery charge based on the temperature information and current vehicle speed information in the power battery status information. This offset can be set according to actual needs. The lower limit of the power battery assist is determined by a one-dimensional lookup table based on the health status of the power battery. Usually, the lower limit of the power battery assist is lower than the median power battery charge with a certain margin. Similarly, the offset of the lower limit of the power battery assist relative to the median power battery charge can be set according to actual needs.

[0099] The forced generation power can be determined based on the relationship between the power battery charge and the forced generation threshold. The forced generation threshold can be determined based on the lower limit of the power battery assist. Usually, the forced generation threshold = lower limit of the power battery assist - hysteresis value. The hysteresis value is a fixed value set by the user and is generally a small number. When the power battery charge is less than or equal to the forced generation threshold, the forced generation power is calculated by looking up the difference between the power battery charge and the forced generation threshold in a one-dimensional table. When the power battery charge is between the lower limit of the power battery assist and the upper limit of the power battery charging limit, the forced generation power is generally 0.

[0100] The forced discharge power is related to the forced discharge threshold and the upper limit of the power battery's driving charge. The forced discharge threshold is related to the prohibited energy recovery threshold. The forced discharge threshold = prohibited energy recovery threshold + hysteresis value. The prohibited energy recovery threshold is calculated by looking up a table based on the power battery temperature. The prohibited energy recovery threshold is usually higher than the upper limit of the driving charge and leaves a certain margin. When the power battery capacity is greater than or equal to the forced discharge threshold, the forced discharge power is calculated by looking up a table based on the difference between the power battery capacity and the forced discharge threshold. When the power battery capacity is between the lower limit of the power battery's assist function and the upper limit of the power battery's driving charge, the forced discharge power is generally 0.

[0101] The power battery balance power is usually determined by the forced generation power, SOC balance charging power, forced discharge power, and SOC balance discharge power, that is, power battery balance power = Max(forced generation power, SOC balance charging power) - Max(forced discharge power, SOC balance discharge power).

[0102] The power battery charge balancing torque is determined by the battery charge balancing power, the front drive motor efficiency, and the engine speed, i.e., power battery charge balancing torque = battery charge balancing power * 9550 / front drive motor efficiency / engine speed. The engine speed is obtained from the engine management system, and the front drive motor efficiency is obtained from the front drive motor control unit.

[0103] S402. Determine the basic torque requirement for direct drive of the engine based on the torque demanded by the driver, the torque demanded by the accessories, and the torque balance of the power battery.

[0104] Among them, the basic torque required for direct drive of the engine = the torque required by the driver + the torque required by the accessories + the torque required to balance the power battery charge.

[0105] S403. Determine the engine load adjustment torque based on engine speed, engine direct drive basic torque requirements, and power battery charge information.

[0106] Among them, engine load adjustment torque includes engine high load adjustment torque and engine low load adjustment torque. When the engine is under high load adjustment torque, it indicates that the engine direct drive basic torque requirement is greater than the upper limit of the preset engine direct drive economic torque range. When the engine is under low load adjustment torque, it indicates that the engine direct drive basic torque requirement is less than the lower limit of the preset engine direct drive economic torque range. The engine high load adjustment torque and low load adjustment torque can be determined by parameters such as engine speed, engine direct drive basic torque requirement, and power battery charge information.

[0107] S404. Determine the initial torque requirements of the front and rear drive motors based on the engine load adjustment torque, accessory power demand torque, SOC balance charging torque, and SOC balance discharging torque.

[0108] Wherein, the initial torque required by the front and rear drive motors = (engine high load adjustment torque + SOC balance discharge torque + (engine low load adjustment torque - SOC balance charging torque) + accessory power demand torque * (-1) * engine to wheel end speed ratio; the SOC balance discharge torque and SOC balance charging torque are determined by the SOC balance discharge power and SOC balance charging power, and the engine to wheel end speed ratio is usually a certain value.

[0109] S405. Determine the actual torque required by the engine based on the driver's required torque and the initial required torque of the front and rear drive motors.

[0110] Wherein, the actual torque required by the engine = ((driver's required torque - initial required torque of the front and rear drive motors) / engine to wheel speed ratio).

[0111] S406. Determine the basic required torque of the front and rear drive motors based on the actual required torque of the engine, the actual torque of the engine, and the initial required torque of the front and rear drive motors.

[0112] Wherein, the basic required torque of the front and rear drive motors = the initial required torque of the front and rear drive motors + (actual required torque of the engine - actual torque of the engine).

[0113] S407. Determine the required torque of the rear drive motor based on the driver's required torque.

[0114] Specifically, the torque required by the driver can be determined by parameters such as the displacement of the pedal and the angle of the steering wheel. The torque required by the rear drive motor is directly related to the torque required by the driver, that is, the torque required by the rear drive motor can also be determined by parameters such as the displacement of the pedal and the angle of the steering wheel.

[0115] S408. Determine the required torque of the front drive motor based on the difference between the basic required torque of the front and rear drive motors and the required torque of the rear drive motor.

[0116] Wherein, the required torque of the front drive motor = the basic required torque of the front and rear drive motors - the required torque of the rear drive motor.

[0117] S409. Based on the target torque requirements of the front drive motor and the target torque requirements of the rear drive motor, determine the required power of the front drive motor and the required power of the rear drive motor respectively.

[0118] The required power of the front drive motor is related to parameters such as the required torque, speed, and main reduction ratio of the front drive motor. The speed of the front drive motor is reported by the front drive motor control unit, and the main reduction ratio is a preset fixed value. The required power of the front drive motor = required torque of the front drive motor * speed of the front drive motor / main reduction ratio / 9550. Similarly, the required power of the rear drive motor is related to parameters such as required torque, speed, and main reduction ratio of the rear drive motor. The speed of the rear drive motor is reported by the rear drive motor control unit. The required power of the rear drive motor = required torque of the rear drive motor * speed of the rear drive motor / main reduction ratio / 9550.

[0119] S410. When the vehicle is in engine direct drive four-wheel drive power generation mode, the target power of the power battery is determined based on the power demand of the front drive motor, the power demand of the rear drive motor, and the power of the accessories.

[0120] S411, Obtain the actual power of the power battery and the charging / discharging capability of the power battery.

[0121] S412. Determine the target feedback control result of the power battery based on the target power of the power battery, the actual power of the power battery, and the charging / discharging capacity of the power battery.

[0122] S413. Based on the target feedback control results of the power battery, the required power of the rear drive motor and the power of the accessories, determine the required power of the front drive motor feedback control.

[0123] S414. Determine the feedback control torque requirement of the front drive motor based on the power requirement of the front drive motor feedback control.

[0124] S415. Based on the feedback control torque demand of the front drive motor, adjust the output torque of the front drive motor and return to execute S411.

[0125] The control method for a three-motor hybrid vehicle provided in this invention first acquires the driver's required torque, accessory power required torque, power battery charge balance torque, engine actual torque, engine speed, power battery charge information, SOC balance charging torque, and SOC balance discharging torque before determining the target power of the power battery based on the required power of the front drive motor, the required power of the rear drive motor, and the accessory power. Then, it determines the generator direct drive basic required torque and the engine load adjustment torque. Further, it determines the required power of the front drive motor and the required power of the rear drive motor. When the vehicle is in engine direct drive four-wheel drive generator mode, the target power of the power battery can be determined based on the required power of the front drive motor, the required power of the rear drive motor, and the accessory power. Subsequently, based on parameters such as the difference between the target power and the actual power of the power battery, it determines parameters such as the target feedback control result of the power battery and the feedback control required torque of the front drive motor. Then, by adjusting the output torque of the front drive motor, the actual power of the battery quickly reaches the target power.

[0126] Example 5

[0127] Figure 5 This is a flowchart of a control method for a three-motor hybrid vehicle provided in Embodiment 5 of the present invention. Based on the above embodiments, this method is applicable to situations where the actual torque demand of the engine is determined according to the driver's required torque and the initial required torque of the front and rear drive motors. Figure 5 As shown, the method includes:

[0128] S501: Obtain the driver's required torque, accessory power required torque, power battery charge balance torque, engine actual torque, engine speed, power battery charge information, SOC balance charging torque, and SOC balance discharging torque.

[0129] S502. Determine the basic torque requirement for direct drive of the engine based on the torque demanded by the driver, the torque demanded by the accessories, and the torque balance of the power battery.

[0130] S503: Determine the engine load adjustment torque based on engine speed, engine direct drive basic torque requirements, and power battery charge information.

[0131] S504. Determine the initial torque requirements of the front and rear drive motors based on the engine load adjustment torque, accessory power demand torque, SOC balance charging torque, and SOC balance discharging torque.

[0132] S505: Obtain the speed ratio from the engine to the wheel end.

[0133] The speed ratio from the engine to the wheels is a fixed value set by the vehicle itself.

[0134] S506. A formula for calculating engine torque demand is constructed based on the driver's required torque, the initial required torque of the front and rear drive motors, and the speed ratio from the engine to the wheel ends.

[0135] The formula for calculating the engine torque demand is: Engine torque demand = (Driver torque demand - Initial torque demand of front and rear drive motors) / Engine-to-wheel speed ratio.

[0136] S507. Determine whether the engine demand torque calculated based on the engine demand torque calculation formula is between the upper limit of the engine demand torque capacity and the lower limit of the engine demand torque; if yes, execute S508; if no, execute S509.

[0137] S508. The engine demand torque calculated based on the engine demand torque calculation formula shall be determined as the actual engine demand torque.

[0138] S509. When the engine demand torque calculated based on the engine demand torque calculation formula is less than or equal to the lower limit of the engine demand torque, the lower limit of the engine demand torque shall be determined as the actual engine demand torque; when the engine demand torque calculated based on the engine demand torque calculation formula is greater than or equal to the upper limit of the engine demand torque, the upper limit of the engine demand torque shall be determined as the actual engine demand torque.

[0139] Specifically, based on the acquired driver's required torque, the initial required torque of the front and rear drive motors, and the engine-to-wheel speed ratio, the engine's required torque is calculated using a constructed formula. The system determines whether the required engine torque falls between the upper and lower limits of the engine's required torque capacity. If so, the calculated engine required torque is considered within the engine's required torque capacity range and is determined as the actual required engine torque. When the calculated engine required torque is less than or equal to the lower limit, it is considered to exceed the lower limit of the engine's required torque capacity range, and the lower limit is determined as the actual required engine torque. Conversely, when the calculated engine required torque is greater than or equal to the upper limit, it is considered to exceed the upper limit of the engine's required torque capacity range, and the upper limit is determined as the actual required engine torque. This method of setting the actual required engine torque ensures that it remains between the upper and lower limits of the engine's required torque capacity range and does not exceed this range.

[0140] S510. Determine the basic required torque of the front and rear drive motors based on the actual required torque of the engine, the actual torque of the engine, and the initial required torque of the front and rear drive motors.

[0141] Wherein, the basic required torque of the front and rear drive motors = the initial required torque of the front and rear drive motors + (actual required torque of the engine - actual torque of the engine).

[0142] S511. Determine the required torque of the rear drive motor based on the driver's required torque.

[0143] S512. Determine the required torque of the front drive motor based on the difference between the basic required torque of the front and rear drive motors and the required torque of the rear drive motor.

[0144] S513. Based on the target torque requirement of the front drive motor and the target torque requirement of the rear drive motor, determine the required power of the front drive motor and the required power of the rear drive motor respectively.

[0145] S514. When the vehicle is in the engine direct drive four-wheel drive power generation mode, the target power of the power battery is determined based on the power demand of the front drive motor, the power demand of the rear drive motor, and the power of the accessories.

[0146] S515: Obtain the actual power of the power battery and the charging / discharging capability of the power battery.

[0147] S516. Determine the target feedback control result of the power battery based on the target power of the power battery, the actual power of the power battery, and the charging / discharging capacity of the power battery.

[0148] S517. Based on the target feedback control results of the power battery, the required power of the rear drive motor and the power of the accessories, determine the required power of the front drive motor feedback control.

[0149] S518. Determine the feedback control torque of the front drive motor based on the power required for feedback control of the front drive motor.

[0150] S519. Based on the feedback control torque demand of the front drive motor, adjust the output torque of the front drive motor and return to execute S515.

[0151] The control method for a three-motor hybrid vehicle provided in this invention determines the actual engine torque demand based on the driver's required torque and the initial required torque of the front and rear drive motors. First, the speed ratio from the engine to the wheels is obtained. Then, the engine torque demand is calculated using the engine torque demand calculation formula. It is determined whether the engine torque demand falls between the upper and lower limits of the engine torque demand capability, thus determining the actual engine torque demand. This actual engine torque demand is consistently maintained between the upper and lower limits, ensuring the accuracy of subsequent calculations based on the actual engine torque demand. Next, parameters such as the target feedback control result of the power battery and the feedback control torque demand of the front drive motor are determined. Finally, the output torque of the front drive motor is adjusted to rapidly bring the battery's actual power to the target power.

[0152] Example 6

[0153] Figure 6 This is a flowchart of a control method for a three-motor hybrid vehicle provided in Embodiment Six of the present invention. Based on the above embodiments, this embodiment explains how to determine the basic required torque of the front and rear drive motors according to the actual required torque of the engine, the actual engine torque, and the initial required torque of the front and rear drive motors. For example... Figure 6 As shown, the method includes:

[0154] S601, obtain the driver's required torque, accessory power required torque, power battery charge balance torque, engine actual torque, engine speed, power battery charge information, SOC balance charging torque and SOC balance discharging torque.

[0155] S602. Determine the basic torque requirement for direct drive of the engine based on the torque demanded by the driver, the torque demanded by the accessories, and the torque balance of the power battery.

[0156] S603: Determine the engine load adjustment torque based on engine speed, engine direct drive basic torque requirements, and power battery charge information.

[0157] S604. Determine the initial torque requirements of the front and rear drive motors based on the engine load adjustment torque, accessory power demand torque, SOC balance charging torque, and SOC balance discharging torque.

[0158] S605. Determine the actual torque required by the engine based on the driver's required torque and the initial required torque of the front and rear drive motors.

[0159] S606. Based on the actual required torque of the engine, the actual torque of the engine, and the initial required torque of the front and rear drive motors, a formula for calculating the sum of the required torques of the front and rear drive motors is constructed.

[0160] The formula for calculating the sum of the required torques of the front and rear drive motors is: Sum of required torques of the front and rear drive motors = Initial required torques of the front and rear drive motors + (Actual required torque of the engine - Actual torque of the engine).

[0161] S607. Determine whether the sum of the required torques of the front and rear drive motors calculated based on the formula for the sum of the required torques of the front and rear drive motors is between the maximum positive torque capacity and the maximum negative torque capacity of the front and rear drive motors; if yes, execute S608; if no, execute S609.

[0162] S608. The sum of the required torques of the front and rear drive motors, calculated based on the formula for the sum of the required torques of the front and rear drive motors, shall be determined as the basic required torques of the front and rear drive motors.

[0163] S609. When the sum of the required torques of the front and rear drive motors calculated based on the formula for the sum of the required torques of the front and rear drive motors is less than or equal to the maximum negative torque capacity of the front and rear drive motors, the maximum negative torque capacity of the front and rear drive motors shall be determined as the basic required torque of the front and rear drive motors; when the sum of the required torques of the front and rear drive motors calculated based on the formula for the sum of the required torques of the front and rear drive motors is greater than or equal to the maximum positive torque capacity of the front and rear drive motors, the maximum positive torque capacity of the front and rear drive motors shall be determined as the basic required torque of the front and rear drive motors.

[0164] Among them, the capabilities of the front and rear drive motors are reported by the front drive motor control unit and the rear drive motor control unit. The maximum positive torque capability of the front and rear drive motors = Min((power battery discharge capability - accessory power) + the sum of the positive torque capabilities of the front and rear drive motors), and the maximum negative torque capability of the front and rear drive motors = Min((power battery charging capability + accessory power) + the sum of the negative torque capabilities of the front and rear drive motors) * (-1).

[0165] Specifically, the required torque of the engine is calculated based on the actual torque demanded by the engine and the initial torque demanded by the front and rear drive motors, using a formula for calculating the sum of the required torques of the front and rear drive motors. It is then determined whether the calculated sum of the required torques of the front and rear drive motors falls between the maximum positive torque capacity and the maximum negative torque capacity of the front and rear drive motors. If so, the sum of the required torques of the front and rear drive motors is considered to be within the torque range of the front and rear drive motors, and is thus determined as the basic required torque of the front and rear drive motors. When the sum of the required torques of the front and rear drive motors is less than or equal to the maximum negative torque capacity of the front and rear drive motors, the sum of the required torques of the front and rear drive motors is considered to exceed the lower limit of the negative torque range of the front and rear drive motors, and is thus determined as the basic required torque of the front and rear drive motors. When the sum of the required torques of the front and rear drive motors, calculated using the formula for the sum of the required torques of the front and rear drive motors, is greater than or equal to the maximum positive torque capacity of the front and rear drive motors, it is considered that the sum of the required torques of the front and rear drive motors exceeds the upper limit of the positive torque range of the front and rear drive motors. Therefore, the maximum positive torque capacity of the front and rear drive motors is determined as the basic required torque of the front and rear drive motors. This method of setting the basic required torque of the front and rear drive motors ensures that the basic required torque remains between the maximum positive torque capacity and the maximum negative torque capacity of the front and rear drive motors, and will not exceed this range.

[0166] S610: Determine the required torque of the rear drive motor based on the driver's required torque.

[0167] S611. Determine the required torque of the front drive motor based on the difference between the basic required torque of the front and rear drive motors and the required torque of the rear drive motor.

[0168] S612. Based on the target torque requirements of the front drive motor and the target torque requirements of the rear drive motor, determine the required power of the front drive motor and the required power of the rear drive motor respectively.

[0169] S613. When the vehicle is in the engine direct drive four-wheel drive power generation mode, the target power of the power battery is determined based on the power demand of the front drive motor, the power demand of the rear drive motor, and the power of the accessories.

[0170] S614. Obtain the actual power of the power battery and the charging / discharging capability of the power battery.

[0171] S615. Determine the target feedback control result of the power battery based on the target power of the power battery, the actual power of the power battery, and the charging / discharging capacity of the power battery.

[0172] S616. Based on the target feedback control results of the power battery, the required power of the rear drive motor and the power of the accessories, determine the required power of the front drive motor feedback control.

[0173] S617. Determine the feedback control torque of the front drive motor based on the power required for feedback control of the front drive motor.

[0174] S618. Based on the feedback control torque demand of the front drive motor, adjust the output torque of the front drive motor and return to execute S614.

[0175] The control method for a three-motor hybrid vehicle provided in this invention calculates the sum of the required torques of the front and rear drive motors based on the actual required torque of the engine, the actual engine torque, and the initial required torques of the front and rear drive motors. It then determines whether the calculated sum of the required torques falls between the maximum positive torque capacity and the maximum negative torque capacity of the front and rear drive motors. This ensures that the basic required torque of the front and rear drive motors remains within this range, guaranteeing that subsequent calculations based on the basic required torques are accurate. Next, parameters such as the target feedback control result of the power battery and the feedback control required torque of the front drive motor are determined. Finally, by adjusting the output torque of the front drive motor, the actual power of the battery quickly reaches the target power.

[0176] Example 7

[0177] Based on the above embodiments, Figure 7 This is a flowchart of a control method for a three-motor hybrid vehicle provided in Embodiment 7 of the present invention. This method is applicable before each return to the execution of the step of obtaining the actual power of the power battery and the charging / discharging capacity of the power battery. This method can be executed by the control device provided in this embodiment of the invention, which is implemented in hardware and / or software. Figure 7 As shown, the method includes:

[0178] S701, obtains the driver's required torque, accessory power required torque, power battery charge balance torque, engine actual torque, engine speed, power battery charge information, SOC balance charging torque and SOC balance discharging torque.

[0179] S702. Determine the basic torque requirement for direct drive of the engine based on the torque demanded by the driver, the torque demanded by the accessories, and the torque balance of the power battery.

[0180] S703 determines the engine load adjustment torque based on engine speed, engine direct drive basic torque requirements, and power battery charge information.

[0181] S704. Determine the initial torque requirements of the front and rear drive motors based on the engine load adjustment torque, accessory power demand torque, SOC balance charging torque, and SOC balance discharging torque.

[0182] S705. Determine the actual torque required by the engine based on the driver's required torque and the initial required torque of the front and rear drive motors.

[0183] S706. Determine the basic required torque of the front and rear drive motors based on the actual required torque of the engine, the actual torque of the engine, and the initial required torque of the front and rear drive motors.

[0184] S707: Determine the required torque of the rear drive motor based on the driver's required torque.

[0185] S708. Determine the required torque of the front drive motor based on the difference between the basic required torque of the front and rear drive motors and the required torque of the rear drive motor.

[0186] S709. Based on the target torque requirement of the front drive motor and the target torque requirement of the rear drive motor, determine the required power of the front drive motor and the required power of the rear drive motor respectively.

[0187] S710. When the vehicle is in engine direct drive four-wheel drive power generation mode, the target power of the power battery is determined based on the power demand of the front drive motor, the power demand of the rear drive motor, and the power of the accessories.

[0188] S711, Obtain the actual power of the power battery and the charging / discharging capability of the power battery.

[0189] S712. Determine the target feedback control result of the power battery based on the target power of the power battery, the actual power of the power battery, and the charging / discharging capacity of the power battery.

[0190] S713. Based on the target feedback control results of the power battery, the required power of the rear drive motor and the power of the accessories, determine the required power of the front drive motor feedback control.

[0191] S714. Determine the feedback control torque of the front drive motor based on the power required for feedback control of the front drive motor.

[0192] S715. Determine the engine feedback control torque based on the engine's actual torque requirement, the front drive motor feedback control torque requirement, and the front drive motor's torque requirement.

[0193] Wherein, the engine feedback control required torque = engine actual required torque + (front drive motor feedback control required torque - front drive motor required torque) / engine to wheel end speed ratio * (-1).

[0194] S716: Adjusts the engine's output torque based on the engine feedback control torque demand.

[0195] S717. Based on the feedback control torque demand of the front drive motor, adjust the output torque of the front drive motor and return to execute S711.

[0196] Specifically, based on the calculated engine feedback control torque demand and front drive motor feedback control torque demand, the output torques of the engine and front drive motor are adjusted. The output torque of the front drive motor is related to the engine output torque; adjusting the engine output torque can adjust the output torque of the front drive motor. That is, the engine output torque serves as the power source for the front drive motor; when the output torque of the front drive motor needs to be adjusted, the engine output torque can be adjusted simultaneously to achieve a balance in power demand. After adjusting the engine and front drive motor output torques, the process returns to obtain the actual power of the battery and its charging / discharging capacity. If the actual power of the battery is equal to the target power, there is no need to further determine the battery target feedback control result. If there is still a gap between the actual power of the battery and the target power, the battery target feedback control result is determined again, thereby determining the front drive motor feedback control torque demand and the engine feedback control torque demand. This is used to adjust the engine output torque and the front drive motor output torque so that the final actual power of the battery can equal the target power.

[0197] The control method for a three-motor hybrid vehicle provided in this invention first acquires the driver's required torque, accessory power required torque, power battery charge balance torque, engine actual torque, engine speed, power battery charge information, SOC balance charging torque, and SOC balance discharging torque before determining the target power of the power battery based on the required power of the front drive motor, the required power of the rear drive motor, and the accessory power. Then, it determines the generator direct drive basic required torque and the engine load adjustment torque. Further, it determines the required power of the front drive motor and the required power of the rear drive motor. When the vehicle is in engine direct drive four-wheel drive generator mode, the target power of the power battery can be determined based on the required power of the front drive motor, the required power of the rear drive motor, and the accessory power. Subsequently, based on parameters such as the difference between the target power and the actual power of the power battery, it determines parameters such as the target feedback control result of the power battery and the feedback control required torque of the front drive motor. Then, by adjusting the output torque of the front drive motor, the actual power of the battery quickly reaches the target power.

[0198] Example 8

[0199] Figure 8 This is a flowchart of a control method for a three-motor hybrid vehicle provided in Embodiment 8 of the present invention. Based on the above embodiments, this embodiment describes the situation before determining the target power of the power battery based on the required power of the front drive motor, the required power of the rear drive motor, and the power of the accessories. Figure 8 As shown, the method specifically includes:

[0200] S801: Obtain the driver's required torque, accessory power required torque, power battery charge balance torque, engine actual torque, engine speed, power battery charge information, SOC balance charging torque, and SOC balance discharging torque.

[0201] S802. Determine the basic torque requirement for direct drive of the engine based on the torque demanded by the driver, the torque demanded by the accessories, and the torque balance of the power battery.

[0202] S803 determines the engine load adjustment torque based on engine speed, engine direct drive basic torque requirements, and power battery charge information.

[0203] S804. Determine the initial required torque of the front and rear drive motors based on the engine load adjustment torque, accessory power demand torque, SOC balance charging torque, and SOC balance discharging torque.

[0204] S805. Determine the actual torque required by the engine based on the driver's required torque and the initial required torque of the front and rear drive motors.

[0205] S806. Determine the basic required torque of the front and rear drive motors based on the actual required torque of the engine, the actual torque of the engine, and the initial required torque of the front and rear drive motors.

[0206] S807. Determine the required torque of the rear drive motor based on the driver's required torque.

[0207] S808. Determine the required torque of the front drive motor based on the difference between the basic required torque of the front and rear drive motors and the required torque of the rear drive motor.

[0208] S809. Based on the target torque requirement of the front drive motor and the target torque requirement of the rear drive motor, determine the required power of the front drive motor and the required power of the rear drive motor respectively.

[0209] S810: Based on the engine direct drive basic torque requirement and power battery charge information, determine whether the vehicle has entered engine direct drive mode; if so, execute S811.

[0210] Specifically, based on the obtained basic torque requirement for direct engine drive and power battery charge information, it is compared with the corresponding parameter range in engine direct drive mode. If the obtained basic torque requirement for direct engine drive and power battery charge information are within the corresponding parameter range in engine direct drive mode, then the vehicle is determined to enter engine direct drive mode; otherwise, it is not.

[0211] S811. Determine whether the time it takes for the vehicle to enter engine direct drive mode is greater than the first preset time; if so, execute S812.

[0212] Specifically, the first preset time is a pre-set time. If the vehicle enters the engine direct drive mode, the timer starts from the time of entering the mode. It is determined whether the time of entering the engine direct drive mode is greater than the first preset time. If so, it is considered that the vehicle has stably entered the engine direct drive mode and the subsequent judgment continues. If not, it is considered that the vehicle has not entered the engine direct drive mode.

[0213] S812. Determine whether the vehicle is in a state where the front motor generates electricity and the rear motor drives it; if so, execute S813.

[0214] Specifically, when the vehicle is in a state where the front motor generates electricity and the rear motor drives it, the front drive motor is in a state of generating electricity and the rear drive motor is in a state of driving.

[0215] Specifically, if the vehicle enters engine direct drive mode for a time longer than a first preset time, it is further determined whether the vehicle is in a state where the front motor generates electricity and the rear motor drives it. If the front drive motor is generating electricity and the rear drive motor is driving, the vehicle is considered to be in a state where the front motor generates electricity and the rear motor drives it, and the subsequent judgment process continues. Otherwise, it is considered that the vehicle has not entered a state where the front motor generates electricity and the rear motor drives it, and no further judgment process is required.

[0216] S813. Determine whether the time the vehicle has been in the state of being driven by the front motor after the front motor generates electricity is greater than the second preset time; if so, execute S814.

[0217] S814. Confirm that the vehicle is in engine direct drive four-wheel drive power generation mode.

[0218] Specifically, the second preset time is also a pre-set time. If the vehicle enters the state of front motor power generation and motor drive, the timer starts from the time of entering the mode and it is determined whether the time of entering the state of front motor power generation and motor drive is greater than the second preset time. If so, it is considered that the vehicle has been stably in the engine direct drive four-wheel drive power generation mode. If not, it is considered that the vehicle has not entered the engine direct drive four-wheel drive power generation mode.

[0219] S815. When the vehicle is in engine direct drive four-wheel drive power generation mode, the target power of the power battery is determined based on the power demand of the front drive motor, the power demand of the rear drive motor, and the power of the accessories.

[0220] S816, obtain the actual power of the power battery and the charging / discharging capability of the power battery.

[0221] S817. Determine the target feedback control result of the power battery based on the target power of the power battery, the actual power of the power battery, and the charging / discharging capacity of the power battery.

[0222] S818. Based on the target feedback control results of the power battery, the required power of the rear drive motor and the power of the accessories, determine the required power of the front drive motor feedback control.

[0223] S819. Determine the feedback control torque of the front drive motor based on the power required for feedback control of the front drive motor.

[0224] S820: Based on the feedback control torque demand of the front drive motor, adjust the output torque of the front drive motor and return to execute S816.

[0225] The control method for a three-motor hybrid vehicle provided in this invention determines whether the vehicle has entered engine direct drive mode based on the engine direct drive basic torque requirement and the power battery charge information before determining the target power of the power battery based on the power demand of the front drive motor, the power demand of the rear drive motor, and the accessory power. Secondly, by successively determining whether the time for the vehicle to enter engine direct drive mode is greater than a first preset time and whether the time for the vehicle to be in the front motor generating and rear motor driving state is greater than a second preset time, it is determined whether the vehicle is stably in engine direct drive four-wheel drive power generation mode. After the engine direct drive four-wheel drive power generation mode is stable, the actual power of the power battery is adjusted to prevent fluctuations in the required torque of the front and rear drive motors before feedback control.

[0226] Example 9

[0227] Based on the above embodiments, Figure 9 This is a flowchart of a control method for a three-motor hybrid vehicle provided in Embodiment 9 of the present invention. This method is applicable to situations where the engine load adjustment torque is determined based on engine speed, the engine's direct-drive basic torque requirement, and the power battery charge information. Figure 9 As shown, the method includes:

[0228] S901: Obtain the driver's required torque, accessory power required torque, power battery charge balance torque, engine actual torque, engine speed, power battery charge information, SOC balance charging torque, and SOC balance discharging torque.

[0229] S902. Determine the basic torque requirement for direct drive of the engine based on the torque demanded by the driver, the torque demanded by the accessories, and the torque balance of the power battery.

[0230] S903: Obtain the vehicle's maximum charging limit and minimum assist limit.

[0231] Specifically, the median value of the power battery charge is set based on the power battery temperature and vehicle speed. The upper limit of the power battery charging during driving is determined by shifting the median value upward by a certain amount. The lower limit of the power battery assist is calculated by a one-dimensional lookup table based on the battery health status, ensuring that the lower limit of the power battery assist is lower than the median value and leaves a certain margin.

[0232] S904. Determine whether the basic torque requirement for direct drive of the engine is within the torque range of the engine's direct drive economic zone; if not, proceed to S905; if yes, proceed to S906.

[0233] Specifically, the upper and lower limits of the engine's direct-drive economic torque are calculated using a one-dimensional lookup table based on engine speed. Generally, the upper limit of the engine's direct-drive economic torque is higher than the lower limit but lower than the engine's external characteristic curve. Based on the upper and lower limits of the engine's direct-drive economic torque obtained from the lookup table, the range of the engine's direct-drive economic torque can be determined, and then it can be judged whether the engine's basic direct-drive torque requirement is within the range of the engine's direct-drive economic torque.

[0234] S905. When the basic torque requirement of the engine direct drive is less than the lower limit of the torque range of the engine direct drive economic zone, the target value of the engine direct drive low-load adjustment torque is determined based on the engine speed and the lower limit of the torque range of the engine direct drive economic zone. The engine direct drive low-load adjustment torque is determined based on the upper limit of vehicle charging, power battery charge information, the basic torque requirement of the engine direct drive, and the target value of the engine direct drive low-load adjustment torque. Alternatively, when the basic torque requirement of the engine direct drive is greater than the upper limit of the torque range of the engine direct drive economic zone, the engine direct drive high-load adjustment torque is determined based on the basic torque requirement of the engine direct drive and the upper limit of the torque range of the engine direct drive economic zone.

[0235] Specifically, if the basic torque requirement of the engine direct drive is not within the torque range of the engine direct drive economic zone, then when the basic torque requirement of the engine direct drive is less than the lower limit of the torque range of the engine direct drive economic zone, the engine direct drive load is considered to be in a low load zone. At this time, the engine load should be increased as much as possible to bring it into the torque range of the engine direct drive economic zone. Among them, the engine direct drive low load adjustment torque is related to the upper limit of vehicle charging, the power battery charge information, the basic torque requirement of the engine direct drive, and the target value of the engine direct drive low load adjustment torque. The target value of the engine direct drive low load adjustment torque can be calculated by one-dimensional lookup table using engine speed. Generally, the target value of the engine direct drive low load adjustment torque is not lower than the lower limit of the torque range of the engine direct drive economic zone. When the power battery charge is greater than or equal to the upper limit of the power battery charging, the current engine direct drive low load adjustment torque can be considered to be 0. When the power battery charge is less than the difference between the upper limit of the power battery charging and the hysteresis value, the engine direct drive low load adjustment torque = (target value of engine direct drive low load adjustment torque - basic torque requirement of engine direct drive) * (-1) * engine to wheel end speed ratio. That is, the engine direct drive low load adjustment torque = Min(0, (engine direct drive low load adjustment torque target value - engine direct drive basic required torque) * (-1) * engine to wheel end speed ratio).

[0236] Correspondingly, when the basic torque requirement for direct drive is greater than the upper limit of the torque range of the engine's direct drive economic zone, the engine's direct drive load is considered to be in the high-load zone. In this case, the engine load should be reduced as much as possible to bring it into the torque range of the engine's direct drive economic zone. At this point, the engine's direct drive high-load adjustment torque can be determined based on the engine's basic torque requirement and the upper limit of the engine's direct drive economic zone torque range, i.e., Engine direct drive high-load adjustment torque = Max(0, (Engine direct drive basic torque requirement - Engine direct drive economic zone torque upper limit) * Engine-to-wheel speed ratio).

[0237] S906. Determine the engine load adjustment torque based on the SOC balance charging torque and / or SOC balance discharging torque.

[0238] Specifically, if the engine direct drive basic torque requirement is within the engine direct drive economic torque range, and the engine direct drive load is considered to be in the medium load range, then the generator load adjustment torque is determined based on the SOC balance charging torque and / or SOC balance discharging torque.

[0239] S907. After determining the engine direct drive low-load adjustment torque, determine the low-load motor demand torque based on the difference between the engine direct drive low-load adjustment torque and the SOC balance charging torque.

[0240] Optionally, determining the low-load motor torque requirement based on the difference between the engine direct-drive low-load adjustment torque and the SOC balance charging torque specifically includes: determining whether the difference between the engine direct-drive low-load adjustment torque and the SOC balance charging torque is greater than the power battery charging capacity; if the difference is greater than the power battery charging capacity, then determining whether the difference is greater than the maximum negative torque capacity of the front and rear drive motors; if the difference is greater than the maximum negative torque capacity of the front and rear drive motors, then determining the difference between the engine direct-drive low-load adjustment torque and the SOC balance charging torque as the low-load motor torque requirement. If the difference between the engine direct drive low-load adjustment torque and the SOC balance charging torque is less than or equal to the power battery charging capacity, then determine whether the power battery charging capacity is greater than the maximum negative torque capacity of the front and rear drive motors. If the power battery charging capacity is greater than the maximum negative torque capacity of the front and rear drive motors, then determine the power battery charging capacity as the low-load motor demand torque. If the difference between the engine direct drive low-load adjustment torque and the SOC balance charging torque is less than or equal to the maximum negative torque capacity of the front and rear drive motors, or if the power battery charging capacity is less than or equal to the maximum negative torque capacity of the front and rear drive motors, then determine the maximum negative torque capacity of the front and rear drive motors as the low-load motor demand torque.

[0241] Specifically, the difference between the engine direct-drive low-load adjustment torque and the SOC balance charging torque is first limited by using the power battery discharge capacity (positive value) as the upper limit and the power battery charging capacity (negative value) as the lower limit. Then, the difference between the engine direct-drive low-load adjustment torque and the SOC balance charging torque is limited a second time by using the maximum positive torque capacity of the front and rear drive motors as the upper limit and the maximum negative torque capacity of the front and rear drive motors as the lower limit. This ensures that the difference between the engine direct-drive low-load adjustment torque and the SOC balance charging torque does not exceed the range between the power battery discharge capacity and the power battery charging capacity, nor does it exceed the range between the maximum positive torque capacity and the maximum negative torque capacity of the front and rear drive motors. Specifically, when the difference between the engine's direct-drive low-load adjustment torque and the SOC balancing charging torque falls within the range between the power battery's discharge capacity and charging capacity, and between the maximum positive torque capacity and the maximum negative torque capacity of the front and rear drive motors, the difference between the engine's direct-drive low-load adjustment torque and the SOC balancing charging torque can be directly determined as the low-load motor's required torque. When the difference between the engine's direct-drive low-load adjustment torque and the SOC balancing charging torque is less than or equal to the power battery's charging capacity, and the power battery's charging capacity is greater than the maximum negative torque capacity of the front and rear drive motors, the power battery's charging capacity can be determined as the low-load motor's required torque. When the difference between the engine's direct-drive low-load adjustment torque and the SOC balancing charging torque is greater than the power battery's charging capacity but less than the maximum negative torque capacity of the front and rear drive motors, the maximum negative torque capacity of the front and rear drive motors can be determined as the low-load motor's required torque. Alternatively, when the difference between the engine's direct-drive low-load adjustment torque and the SOC balancing charging torque is less than or equal to the power battery's charging capacity, and the power battery's charging capacity is less than or equal to the maximum negative torque capacity of the front and rear drive motors, the maximum negative torque capacity of the front and rear drive motors can be determined as the low-load motor's required torque.

[0242] S908. After determining the engine direct drive high load adjustment torque, the high load motor demand torque is determined based on the sum of the engine direct drive high load adjustment torque and the SOC balance discharge torque.

[0243] Optionally, the required torque of the high-load motor is determined based on the sum of the engine direct-drive high-load adjustment torque and the SOC balance discharge torque, including: determining whether the sum of the engine direct-drive high-load adjustment torque and the SOC balance discharge torque is less than the power battery discharge capacity; if the sum of the engine direct-drive high-load adjustment torque and the SOC balance discharge torque is less than the power battery discharge capacity, then determining whether the sum of the engine direct-drive high-load adjustment torque and the SOC balance discharge torque is less than the maximum positive torque capacity of the front and rear drive motors; if the sum of the engine direct-drive high-load adjustment torque and the SOC balance discharge torque is less than the maximum positive torque capacity of the front and rear drive motors, then the engine direct-drive high-load adjustment torque and the SOC balance discharge torque are adjusted accordingly. The torque required for the high-load motor is determined as follows: If the sum of the engine direct-drive high-load adjustment torque and the SOC balance discharge torque is greater than or equal to the power battery discharge capacity, it is determined whether the power battery discharge capacity is less than the maximum positive torque capacity of the front and rear drive motors; if the power battery discharge capacity is less than the maximum negative torque capacity of the front and rear drive motors, the power battery discharge capacity is determined as the torque required for the high-load motor; if the sum of the engine direct-drive high-load adjustment torque and the SOC balance discharge torque is greater than or equal to the maximum positive torque capacity of the front and rear drive motors, or if the power battery discharge capacity is greater than or equal to the maximum positive torque capacity of the front and rear drive motors, the maximum positive torque capacity of the front and rear drive motors is determined as the torque required for the high-load motor.

[0244] Specifically, the sum of the engine's direct-drive high-load adjustment torque and the SOC balance discharge torque is first limited by using the power battery's discharge capacity (positive value) as the upper limit and the power battery's charging capacity (negative value) as the lower limit. Then, the sum of the engine's direct-drive high-load adjustment torque and the SOC balance discharge torque is secondly limited by using the maximum positive torque capacity of the front and rear drive motors as the upper limit and the maximum negative torque capacity of the front and rear drive motors as the lower limit. This ensures that the sum of the engine's direct-drive high-load adjustment torque and the SOC balance discharge torque will not exceed the range between the power battery's discharge capacity and charging capacity, nor will it exceed the range between the maximum positive torque capacity and the maximum negative torque capacity of the front and rear drive motors. Specifically, when the sum of the engine's direct-drive high-load adjustment torque and the SOC balance discharge torque falls within the range between the power battery's discharge capacity and charging capacity, and between the maximum positive torque capacity and the maximum negative torque capacity of the front and rear drive motors, the sum of the engine's direct-drive high-load adjustment torque and the SOC balance discharge torque can be directly determined as the high-load motor's required torque. When the sum of the engine's direct-drive high-load adjustment torque and the SOC balance discharge torque is greater than or equal to the power battery's discharge capacity, and the power battery's discharge capacity is less than the maximum positive torque capacity of the front and rear drive motors, the power battery's discharge capacity can be determined as the high-load motor's required torque. When the sum of the engine's direct-drive high-load adjustment torque and the SOC balance discharge torque is less than the power battery's discharge capacity but greater than or equal to the maximum positive torque capacity of the front and rear drive motors, the maximum positive torque capacity of the front and rear drive motors can be determined as the high-load motor's required torque. Alternatively, when the sum of the engine's direct-drive high-load adjustment torque and the SOC balance discharge torque is greater than or equal to the power battery's discharge capacity, and the power battery's discharge capacity is greater than or equal to the maximum negative torque capacity of the front and rear drive motors, the maximum positive torque capacity of the front and rear drive motors can be determined as the high-load motor's required torque.

[0245] S909. Determine the initial torque requirements of the front and rear drive motors based on the torque requirements of the low-load motor, the torque requirements of the high-load motor, and the torque requirements of the accessories.

[0246] Wherein, the initial torque required by the front and rear drive motors = (engine direct drive high load adjustment torque + SOC balance discharge torque + (engine direct drive low load adjustment torque - SOC balance charging torque) + accessory power demand torque * (-1) * engine to wheel end speed ratio.

[0247] S910: Determine the actual torque required by the engine based on the driver's required torque and the initial required torque of the front and rear drive motors.

[0248] S911. Determine the basic required torque of the front and rear drive motors based on the actual required torque of the engine, the actual torque of the engine, and the initial required torque of the front and rear drive motors.

[0249] S912. Determine the required torque of the rear drive motor based on the driver's required torque.

[0250] S913. Determine the required torque of the front drive motor based on the difference between the basic required torque of the front and rear drive motors and the required torque of the rear drive motor.

[0251] S914. Based on the target torque requirements of the front drive motor and the target torque requirements of the rear drive motor, determine the required power of the front drive motor and the required power of the rear drive motor respectively.

[0252] S915. When the vehicle is in engine direct drive four-wheel drive power generation mode, the target power of the power battery is determined based on the power demand of the front drive motor, the power demand of the rear drive motor, and the power of the accessories.

[0253] S916, obtain the actual power of the power battery and the charging / discharging capability of the power battery.

[0254] S917. Determine the target feedback control result of the power battery based on the target power of the power battery, the actual power of the power battery, and the charging / discharging capacity of the power battery.

[0255] S918. Based on the target feedback control results of the power battery, the required power of the rear drive motor and the power of the accessories, determine the required power of the front drive motor feedback control.

[0256] S919. Determine the feedback control torque of the front drive motor based on the power required for feedback control of the front drive motor.

[0257] S920: Based on the feedback control torque demand of the front drive motor, adjust the output torque of the front drive motor and return to execute S916.

[0258] The control method for a three-motor hybrid vehicle provided in this invention first obtains the vehicle's driving charging upper limit and driving assist lower limit. Then, it determines whether the engine's direct-drive basic torque requirement is within the engine's direct-drive economic torque range, thereby determining the engine's direct-drive low-load adjustment torque, engine direct-drive high-load adjustment torque, and engine load adjustment torque. Further, based on the above parameters, the SOC balance charging torque, and the SOC balance discharging torque, it determines the low-load motor torque requirement and the high-load motor torque requirement. Then, based on the above parameters, it further determines the initial torque requirements of the front and rear drive motors. Subsequently, it determines parameters such as the target feedback control result of the power battery and the feedback control torque requirement of the front drive motor, and then adjusts the output torque of the front drive motor to quickly bring the battery's actual power to the target power.

[0259] Example 10

[0260] Figure 10This is a schematic diagram of a control device for a three-motor hybrid vehicle according to Embodiment 10 of the present invention. This device is suitable for situations where the battery charge in the vehicle deviates from a target value and can be implemented in hardware and / or software. Figure 10 As shown, the device includes:

[0261] The battery target power determination module 11 is used to determine the target power of the power battery based on the power demand of the front drive motor, the power demand of the rear drive motor, and the power of the accessories when the vehicle is in the engine direct drive four-wheel drive power generation mode.

[0262] Battery capability acquisition module 12 is used to acquire the actual power of the power battery and the charging / discharging capability of the power battery;

[0263] The battery feedback result determination module 13 is used to determine the target feedback control result of the power battery based on the target power of the power battery, the actual power of the power battery, and the charging / discharging capacity of the power battery.

[0264] The front drive motor feedback demand power determination module 14 is used to determine the front drive motor feedback control demand power based on the target feedback control result of the power battery, the demand power of the rear drive motor and the accessory power.

[0265] The front drive motor feedback demand torque determination module 15 determines the front drive motor feedback control demand torque based on the front drive motor feedback control demand power.

[0266] The front drive motor torque adjustment module 16 is used to adjust the output torque of the front drive motor based on the feedback control torque demand of the front drive motor, and return to the execution steps of obtaining the actual power of the power battery and the charging / discharging capacity of the power battery.

[0267] The control device for a three-motor hybrid vehicle provided in this embodiment of the invention is used to execute the control method for a three-motor hybrid vehicle provided in any embodiment of the invention, and has the same beneficial effects as the method, which will not be repeated here.

[0268] Example 11

[0269] A computer-readable storage medium stores computer instructions for causing a processor to execute and implement a control method for a three-motor hybrid vehicle according to any embodiment of the present invention. It has the same beneficial effects as the method, which will not be repeated here.

[0270] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, combinations, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A control method for a three-motor hybrid vehicle, characterized in that, The three-motor hybrid vehicle includes: an engine, an engine management system, a generator, a generator control unit, a generator inverter, a front drive motor, a front drive motor control unit, a front drive motor inverter, a front axle reduction gear, front axle wheels, a rear drive motor, a rear drive motor control unit, a rear drive motor inverter, a rear axle reduction gear, rear axle wheels, a power battery, a battery management system, a clutch, and a vehicle controller; the engine management system is electrically connected to the engine; the generator is electrically connected to the power battery via the generator inverter; the generator control unit is electrically connected to the generator via the generator inverter; the front drive motor is electrically connected to the power battery via the front drive motor inverter; the front drive motor control unit is electrically connected to the front drive motor via the front drive motor inverter. The front drive motor is mechanically connected to the front axle wheels via the front axle reduction gear; the rear drive motor is electrically connected to the power battery via the rear drive motor inverter; the rear drive motor control unit is electrically connected to the rear drive motor via the rear drive motor inverter; the rear drive motor is mechanically connected to the rear axle wheels via the rear axle reduction gear; the battery management system is electrically connected to the power battery; the engine and the generator are connected via a gear pair, and the engine is also mechanically connected to the front axle reduction gear via the clutch; the vehicle controller is communicatively connected to the engine management system, the front drive motor control unit, the rear drive motor control unit, the generator control unit, and the battery management system; the vehicle controller is used to execute the control method of the three-motor hybrid vehicle. The control method for the three-motor hybrid vehicle includes: When the vehicle is in engine direct drive four-wheel drive power generation mode, the target power of the power battery is determined based on the power demand of the front drive motor, the power demand of the rear drive motor, and the power of the accessories. To obtain the actual power of the power battery and its charging / discharging capacity; The target feedback control result of the power battery is determined based on the target power of the power battery, the actual power of the power battery, and the charging / discharging capacity of the power battery. Based on the target feedback control result of the power battery, the required power of the rear drive motor, and the power of the accessory, the required power of the front drive motor feedback control is determined. The feedback control torque of the front drive motor is determined based on the power required for the front drive motor feedback control. Based on the feedback control torque requirement of the front drive motor, adjust the output torque of the front drive motor, and return to the step of obtaining the actual power of the power battery and the charging / discharging capacity of the power battery; Before determining the target power of the power battery based on the power requirements of the front drive motor, the power requirements of the rear drive motor, and the power of accessories, the following steps are also included: It acquires the driver's required torque, accessory power required torque, power battery charge balance torque, engine actual torque, engine speed, power battery charge information, SOC balance charging torque, and SOC balance discharging torque; The basic torque requirement for direct drive of the engine is determined based on the torque demanded by the driver, the torque demanded by the accessories, and the torque balance of the power battery. The engine load adjustment torque is determined based on the engine speed, the engine direct drive basic torque requirement, and the power battery charge information. The initial required torques of the front and rear drive motors are determined based on the engine load adjustment torque, the accessory power demand torque, the SOC balance charging torque, and the SOC balance discharging torque. The actual torque required by the engine is determined based on the driver's required torque and the initial required torque of the front and rear drive motors; The basic required torque of the front and rear drive motors is determined based on the actual required torque of the engine, the actual torque of the engine, and the initial required torque of the front and rear drive motors. The required torque of the rear drive motor is determined based on the driver's required torque. The required torque of the front drive motor is determined based on the difference between the basic required torque of the front and rear drive motors and the required torque of the rear drive motor. Based on the target torque requirement of the front drive motor and the target torque requirement of the rear drive motor, the required power of the front drive motor and the required power of the rear drive motor are determined respectively.

2. The control method for a three-motor hybrid vehicle according to claim 1, characterized in that, Obtain the required torque for the accessory power, including: Obtain the efficiency of the front drive motor, the required power of the high-voltage accessories, and the required power of the low-voltage accessories; The sum of the power requirements of the high-voltage accessory and the power requirements of the low-voltage accessory is determined as the accessory power. The required torque for the accessory power is determined based on the accessory power, the engine speed, and the front drive motor efficiency.

3. The control method for a three-motor hybrid vehicle according to claim 1, characterized in that, Obtaining the power battery charge balance torque includes: Acquire front drive motor efficiency, power battery status information, current vehicle speed information, SOC balance charging power, and SOC balance discharging power; Based on the power battery status information and the current vehicle speed information, the upper limit of power battery charging during driving and the lower limit of power battery assist are determined respectively. Based on the power battery charge information, the upper limit of the power battery charging during driving, and the lower limit of the power battery assist, the forced power generation power and forced discharge power of the power battery are determined. The power battery balance power is determined based on the SOC balance charging power, the SOC balance discharging power, the forced generation power, and the forced discharging power. The power battery balance torque is determined based on the battery power balance, the front drive motor efficiency, and the engine speed.

4. The control method for a three-motor hybrid vehicle according to claim 1, characterized in that, Determining the engine load adjustment torque based on the engine speed, the engine direct drive basic torque requirement, and the power battery charge information includes: Obtain the vehicle's maximum charging limit and minimum assist limit; Determine whether the basic torque requirement for direct drive of the engine is within the torque range of the engine's direct drive economic zone; If not, when the basic direct-drive torque requirement of the engine is less than the lower limit of the engine direct-drive economic torque range, the target value of the engine direct-drive low-load adjustment torque is determined based on the engine speed and the lower limit of the engine direct-drive economic torque range, and the engine direct-drive low-load adjustment torque is determined based on the vehicle charging upper limit, the power battery charge information, the basic direct-drive torque requirement of the engine direct-drive, and the target value of the engine direct-drive low-load adjustment torque; or, when the basic direct-drive torque requirement of the engine direct-drive is greater than the upper limit of the engine direct-drive economic torque range, the engine direct-drive high-load adjustment torque is determined based on the basic direct-drive torque requirement of the engine direct-drive and the upper limit of the engine direct-drive economic torque range. If so, the engine load adjustment torque is determined based on the SOC balance charging torque and / or the SOC balance discharging torque.

5. The control method for a three-motor hybrid vehicle according to claim 4, characterized in that, Based on the engine load adjustment torque, the SOC balance charging torque, and the SOC balance discharging torque, the initial torque requirements for the front and rear drive motors are determined, including: After determining the engine direct drive low load adjustment torque, the low load motor demand torque is determined based on the difference between the engine direct drive low load adjustment torque and the SOC balance charging torque. After determining the engine direct drive high load adjustment torque, the high load motor required torque is determined based on the sum of the engine direct drive high load adjustment torque and the SOC balance discharge torque. The initial torque requirements of the front and rear drive motors are determined based on the torque requirements of the low-load motor, the torque requirements of the high-load motor, and the torque requirements of the accessory power.

6. The control method for a three-motor hybrid vehicle according to claim 5, characterized in that, The low-load motor torque requirement is determined based on the difference between the engine direct-drive low-load regulating torque and the SOC balanced charging torque, including: Determine whether the difference between the engine direct drive low load adjustment torque and the SOC balance charging torque is greater than the power battery charging capacity; If so, determine whether the difference between the engine direct drive low load adjustment torque and the SOC balance charging torque is greater than the maximum negative torque capability of the front and rear drive motors. If so, the difference between the engine direct drive low-load adjustment torque and the SOC balance charging torque is determined as the low-load motor required torque.

7. The control method for a three-motor hybrid vehicle according to claim 6, characterized in that, The method for determining the low-load motor torque requirement based on the difference between the engine direct-drive low-load regulating torque and the SOC balanced charging torque also includes: If the difference between the engine direct drive low load adjustment torque and the SOC balance charging torque is less than or equal to the power battery charging capacity, then it is determined whether the power battery charging capacity is greater than the maximum negative torque capacity of the front and rear drive motors. If so, the charging capacity of the power battery is determined as the torque required by the low-load motor.

8. The control method for a three-motor hybrid vehicle according to claim 7, characterized in that, The method for determining the low-load motor torque requirement based on the difference between the engine direct-drive low-load regulating torque and the SOC balanced charging torque also includes: If the difference between the engine direct drive low-load adjustment torque and the SOC balance charging torque is less than or equal to the maximum negative torque capability of the front and rear drive motors, or if the power battery charging capability is less than or equal to the maximum negative torque capability of the front and rear drive motors, then the maximum negative torque capability of the front and rear drive motors is determined as the required torque of the low-load motor.

9. The control method for a three-motor hybrid vehicle according to claim 5, characterized in that, The high-load motor torque requirement is determined based on the sum of the engine direct-drive high-load regulating torque and the SOC balanced discharge torque, including: Determine whether the sum of the engine direct drive high load regulating torque and the SOC balanced discharge torque is less than the power battery discharge capacity; If so, determine whether the sum of the engine direct drive high load regulating torque and the SOC balanced discharge torque is less than the maximum positive torque capability of the front and rear drive motors. If so, the sum of the engine direct drive high-load regulating torque and the SOC balanced discharge torque is determined as the high-load motor required torque.

10. The control method for a three-motor hybrid vehicle according to claim 9, characterized in that, The high-load demand motor torque is determined based on the sum of the engine direct-drive high-load regulating torque and the SOC balanced discharge torque, and further includes: If the sum of the engine direct drive high load adjustment torque and the SOC balance discharge torque is greater than or equal to the power battery discharge capacity, then it is determined whether the power battery discharge capacity is less than the maximum positive torque capacity of the front and rear drive motors. If so, the discharge capacity of the power battery is determined as the torque required by the high-load motor.

11. The control method for a three-motor hybrid vehicle according to claim 10, characterized in that, The high-load demand motor torque is determined based on the sum of the engine direct-drive high-load regulating torque and the SOC balanced discharge torque, and further includes: If the sum of the engine direct drive high-load adjustment torque and the SOC balanced discharge torque is greater than or equal to the maximum positive torque capability of the front and rear drive motors, or if the power battery discharge capability is greater than or equal to the maximum positive torque capability of the front and rear drive motors, then the maximum positive torque capability of the front and rear drive motors is determined as the torque required by the high-load motor.

12. The control method for a three-motor hybrid vehicle according to claim 1, characterized in that, Based on the driver's required torque and the initial required torque of the front and rear drive motors, the actual required torque of the engine is determined, including: Obtain the speed ratio from the engine to the wheel end; Based on the driver's required torque, the initial required torque of the front and rear drive motors, and the speed ratio from the engine to the wheel end, a formula for calculating the engine's required torque is constructed; the formula for calculating the engine's required torque is: Engine required torque = (Driver's required torque - Initial required torque of the front and rear drive motors) / Speed ​​ratio from the engine to the wheel end; Determine whether the engine demand torque calculated based on the engine demand torque calculation formula is between the upper limit of the engine demand torque capacity and the lower limit of the engine demand torque; If so, the engine demand torque calculated based on the engine demand torque calculation formula shall be determined as the actual engine demand torque; If not, when the engine demand torque calculated based on the engine demand torque calculation formula is less than or equal to the lower limit of the engine demand torque, the lower limit of the engine demand torque is determined as the actual engine demand torque; when the engine demand torque calculated based on the engine demand torque calculation formula is greater than or equal to the upper limit of the engine demand torque, the upper limit of the engine demand torque is determined as the actual engine demand torque.

13. The control method for a three-motor hybrid vehicle according to claim 1, characterized in that, Based on the actual torque demand of the engine, the actual torque of the engine, and the initial torque demand of the front and rear drive motors, the basic torque demand of the front and rear drive motors is determined, including: Based on the actual required torque of the engine, the actual torque of the engine, and the initial required torque of the front and rear drive motors, a formula is constructed to calculate the sum of the required torques of the front and rear drive motors; the formula for calculating the sum of the required torques of the front and rear drive motors is: the sum of the required torques of the front and rear drive motors = the initial required torque of the front and rear drive motors + (actual required torque of the engine - actual torque of the engine). Determine whether the sum of the required torques of the front and rear drive motors, calculated based on the formula for the sum of the required torques of the front and rear drive motors, is between the maximum positive torque capacity and the maximum negative torque capacity of the front and rear drive motors. If so, the sum of the required torques of the front and rear drive motors calculated based on the formula for the sum of the required torques of the front and rear drive motors shall be determined as the basic required torques of the front and rear drive motors. If not, then when the sum of the required torques of the front and rear drive motors calculated based on the formula for the sum of the required torques of the front and rear drive motors is less than or equal to the maximum negative torque capacity of the front and rear drive motors, the maximum negative torque capacity of the front and rear drive motors is determined as the basic required torque of the front and rear drive motors; when the sum of the required torques of the front and rear drive motors calculated based on the formula for the sum of the required torques of the front and rear drive motors is greater than or equal to the maximum positive torque capacity of the front and rear drive motors, the maximum positive torque capacity of the front and rear drive motors is determined as the basic required torque of the front and rear drive motors.

14. The control method for a three-motor hybrid vehicle according to claim 1, characterized in that, Based on the power requirements of the front drive motor, the power requirements of the rear drive motor, and the power of accessories, the target power of the power battery is determined, including: Based on the power requirements of the front drive motor, the power requirements of the rear drive motor, and the power of the accessories, a formula for calculating the target power of the battery is constructed; the formula for calculating the target power of the battery is: target power of battery = (power requirements of front drive motor + power requirements of rear drive motor + power of accessories) * (-1). The target power of the battery is calculated using the aforementioned battery target power calculation formula.

15. The control method for a three-motor hybrid vehicle according to claim 1, characterized in that, Based on the target power of the power battery, the actual power of the power battery, and the charging / discharging capacity of the power battery, the target feedback control result of the power battery is determined, including: The power battery power feedback error is determined based on the difference between the target power of the power battery and the actual power of the power battery. Determine whether the power battery power feedback error is less than a preset power error value; If so, the integral gain coefficient is determined based on the power battery power feedback error; The integral of the product of the power battery power feedback error and the integral gain coefficient over time is determined as the power battery power error integral quantity. The target feedback control result of the power battery is determined based on the integral of the power battery power error, the target power of the power battery, and the charging / discharging capacity of the power battery.

16. The control method for a three-motor hybrid vehicle according to claim 15, characterized in that, The power battery charging / discharging capability includes the power battery charging capability and the power battery discharging capability. Based on the integral of the power battery power error, the target power of the power battery, and the charging / discharging capacity of the power battery, the target feedback control result of the power battery is determined, including: Determine whether the sum of the power battery power error integral and the power battery target power is less than the power battery discharge capacity; If so, determine whether the sum of the power battery power error integral and the power battery target power is greater than the power battery charging capacity; If so, the sum of the power battery power error integral and the power battery target power is determined as the power battery target feedback control result.

17. The control method for a three-motor hybrid vehicle according to claim 16, characterized in that, The determination of the target feedback control result for the power battery, based on the integral of the power battery power error, the target power of the power battery, and the charging / discharging capacity of the power battery, further includes: If the sum of the power battery power error integral and the power battery target power is greater than or equal to the power battery discharge capacity, then the power battery discharge capacity is determined as the power battery target feedback control result.

18. The control method for a three-motor hybrid vehicle according to claim 17, characterized in that, The determination of the target feedback control result for the power battery, based on the integral of the power battery power error, the target power of the power battery, and the charging / discharging capacity of the power battery, further includes: If the sum of the power battery power error integral and the power battery target power is less than or equal to the power battery charging capacity, then the power battery charging capacity is determined as the power battery target feedback control result.

19. The control method for a three-motor hybrid vehicle according to claim 1, characterized in that, Based on the power requirement for feedback control of the front drive motor, the torque requirement for feedback control of the front drive motor is determined, including: Obtain the front drive motor speed and the main reduction ratio; Based on the front drive motor speed, main reduction ratio, and front drive motor feedback control required power, a formula for calculating the front drive motor feedback control required torque is constructed; the formula for calculating the front drive motor feedback control required torque is: front drive motor feedback control required torque = front drive motor feedback control required power * 9550 / front drive motor speed * main reduction ratio * (-1). The required torque for feedback control of the front drive motor is determined according to the formula for calculating the required torque for feedback control of the front drive motor.

20. The control method for a three-motor hybrid vehicle according to claim 1, characterized in that, Before each return to execute the steps of obtaining the actual power of the power battery and the power battery's charge / discharge capacity, the following is also included: The engine feedback control torque is determined based on the actual torque demand of the engine, the feedback control torque demand of the front drive motor, and the torque demand of the front drive motor. Based on the engine feedback control torque requirement, the engine output torque is adjusted.

21. The control method for a three-motor hybrid vehicle according to claim 1, characterized in that, Before determining the target power of the power battery based on the power requirements of the front drive motor, the power requirements of the rear drive motor, and the power of accessories, the following steps are also included: Based on the engine direct drive basic torque requirement and the power battery charge information, determine whether the vehicle enters engine direct drive mode; If so, determine whether the time it takes for the vehicle to enter engine direct drive mode is greater than the first preset time; If so, determine whether the vehicle is in the state of front motor generating electricity and rear motor driving; when the vehicle is in the state of front motor generating electricity and rear motor driving, the front drive motor is in the state of generating electricity and the rear drive motor is in the state of driving. If so, determine whether the time the vehicle is in the state of front motor generating electricity and then being driven by the motor is greater than the second preset time; If so, then the vehicle is determined to be in engine direct drive four-wheel drive power generation mode.

22. A control device for a three-motor hybrid vehicle, characterized in that, include: The battery target power determination module is used to determine the target power of the power battery based on the power demand of the front drive motor, the power demand of the rear drive motor, and the accessory power when the vehicle is in engine direct drive four-wheel drive power generation mode. Before determining the target power of the power battery based on the power demand of the front drive motor, the rear drive motor, and the accessory power, the module further includes: acquiring the driver's required torque, the accessory power required torque, the power battery charge balance torque, the actual engine torque, the engine speed, the power battery charge information, the SOC balance charging torque, and the SOC balance discharging torque; determining the engine direct drive basic required torque based on the driver's required torque, the accessory power required torque, and the power battery charge balance torque; and determining the engine load adjustment torque based on the engine speed, the engine direct drive basic required torque, and the power battery charge information. The following steps are taken: Based on the engine load adjustment torque, the accessory power demand torque, the SOC balance charging torque, and the SOC balance discharging torque, determine the initial demand torque for the front and rear drive motors; based on the driver's demand torque and the initial demand torques of the front and rear drive motors, determine the actual demand torque for the engine; based on the actual demand torque of the engine, the actual engine torque, and the initial demand torques of the front and rear drive motors, determine the basic demand torques for the front and rear drive motors; based on the driver's demand torque, determine the demand torque for the rear drive motor; based on the difference between the basic demand torques of the front and rear drive motors and the demand torque of the rear drive motor, determine the demand torque for the front drive motor; based on the target demand torques of the front and rear drive motors, determine the target power demand for the front and rear drive motors, respectively. The battery capability acquisition module is used to acquire the actual power of the power battery and its charging / discharging capability. The battery feedback result determination module is used to determine the target feedback control result of the power battery based on the target power of the power battery, the actual power of the power battery, and the charging / discharging capacity of the power battery. The front drive motor feedback demand power determination module is used to determine the front drive motor feedback control demand power based on the target feedback control result of the power battery, the demand power of the rear drive motor, and the power of the accessory. The front drive motor feedback demand torque determination module determines the front drive motor feedback control demand torque based on the front drive motor feedback control demand power. The front drive motor torque adjustment module is used to adjust the output torque of the front drive motor based on the feedback control torque demand of the front drive motor, and return to the execution steps of obtaining the actual power of the power battery and the charging / discharging capacity of the power battery.

23. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions that, when executed by a processor, implement the control method for the three-motor hybrid vehicle as described in any one of claims 1-21.

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