Torque limiting method, system and vehicle for dual-bridge electric vehicle

Abstract

The application discloses a torque limiting method and system for a double-bridge motor vehicle and a vehicle, and the method comprises the following steps: obtaining the ratio of the front and rear axle motor based on the driver's intention target torque based on the driver's intention; obtaining the maximum power allowed for driving of the power battery based on the current, voltage and power of the real-time operation of the vehicle; obtaining the difference between the power consumed by the front and rear axle motors and the product of the maximum power allowed for driving of the power battery and the safety factor; limiting the torque of the front and rear axle motors based on the regulation and control of the torque of the front and rear axle motors; and ensuring that the actual discharge power of the power battery does not exceed the maximum real-time discharge power allowed for the power battery, thereby improving the safety of the system and avoiding damage to the power battery; if the power battery is not allowed to be used, the driving torques of the front and rear axle motors are simultaneously output as zero, and the abnormal torque state of one motor driving and the other motor braking does not occur, thereby ensuring the safety of the vehicle.

Description

Technical Field

[0001] This invention belongs to the field of automotive torque technology, and more specifically, relates to a method, system, and vehicle for limiting the torque of a dual-axle motor in an automotive vehicle. Background Technology

[0002] With the continuous depletion of global oil resources and the ongoing development of new energy vehicles, the powertrain configuration using electric motors on both the front and rear axles offers advantages such as good acceleration and strong power, and has become a development trend for high-end electric vehicles and off-road electric vehicles. However, due to its dual-motor configuration, its control becomes more complex. The maximum allowable discharge power of the power battery changes with its state of being, requiring the control index to be based on this maximum allowable discharge power, combined with the current vehicle motion state, to limit the torque of the front and rear axle motors. Failure to limit the torque of the front and rear axle motors may lead to over-discharge of the power battery, damaging battery components; conversely, improper torque limiting may result in abnormal torque, posing a risk to vehicle safety.

[0003] To address the aforementioned issues, patent CN 108944572 A provides a torque limiting method, device, and electric vehicle. This method uses the recovered torque obtained from the power battery's feedback power and a preset torque compensation to determine a torque limit value. This limits the required torque, resulting in smaller changes in deceleration during energy recovery in the electric vehicle, thus improving the driver's experience. However, its torque control is not specifically designed for limiting the power battery of a dual-axle motor and is not applicable to torque control. Therefore, it cannot be directly applied to dual-axle motor vehicles to ensure power battery safety. Summary of the Invention

[0004] This invention limits the torque of the front and rear axle motors to ensure that the actual discharge power of the power battery does not exceed the maximum allowable discharge power of the power battery in real time, thereby improving the safety of the system and preventing damage to the power battery. If the power battery is not allowed to be used, that is, when the maximum allowable power of the power battery for driving is 0, the driving torque of the front and rear axle motors will be output simultaneously and synchronously to 0, and there will be no abnormal torque state where one motor is driving and the other motor is braking, thus ensuring the safety of vehicle driving.

[0005] To achieve the above objectives, according to one aspect of the present invention, a method for limiting the torque of a dual-axle motor vehicle is provided, comprising the following steps:

[0006] S100 obtains the ratio of the target torque of the front and rear axle motors based on the driver's intention.

[0007] The S200 obtains the maximum power that the power battery is allowed to use for driving based on the vehicle's real-time operating current, voltage, and power.

[0008] The S300 obtains the difference between the power consumed by the front and rear axle motors and the product of the maximum power allowed by the power battery for driving and a safety factor. ;

[0009] S400 based on Adjust the torque of the front and rear axle motors.

[0010] Further, S400 includes:

[0011] S401 when When the torque is less than or equal to zero, the torque of the front and rear axle motors does not need to be reduced. When the value is greater than zero, the torque reduction of the front and rear axle motors is calculated based on their speeds:

[0012]

[0013] --Get the difference between the power consumed by the current rear axle motor and the product of the maximum power allowed by the power battery for driving and the safety factor; —The actual speed of the front axle motor; —The actual speed of the rear axle motor; —The current efficiency of the front and rear axle motors; —The ratio of the front and rear axle motors to the target torque based on the driver's intention;

[0014] S402 obtains the target torque of the front and rear axle motors based on the reduced torque of the front and rear axles and the target torque of the front and rear axle motors based on the driver's intention:

[0015]

[0016] in, —Target torque of the front axle motor; —Target torque of the rear axle motor; —The ratio of the front and rear axle motors to the target torque based on the driver's intention; —The front axle motor is based on the driver's intended target torque; — The rear axle motor is based on the driver's intended target torque.

[0017] Furthermore, when When equal to 0, , All values ​​are zero to prevent one motor from being used as a brake motor to drive another motor.

[0018]

[0019] in, —Target torque of the front axle motor; —Target torque of the rear axle motor; —The ratio of the front and rear axle motors to the target torque based on the driver's intention; —The rear axle motor is based on the driver's intended target torque; — Reduce torque on both front and rear axles.

[0020] Furthermore, S200 specifically includes:

[0021] S201 calculates the current consumed by the high-voltage accessories based on the actual current of the power battery and the current of the front and rear axle motors.

[0022] S202 calculates the power consumed by the high-voltage accessory based on the current consumed by the high-voltage accessory and the total voltage of the power battery;

[0023] S203 calculates the maximum power that the power battery can be used for driving based on the power consumed by the high-voltage accessory and the real-time maximum allowable discharge power of the power battery:

[0024]

[0025] in: —The maximum allowable discharge power of the power battery in real time; —The total voltage of the power battery; —Actual current of the power battery; —The actual current of the front axle motor; —The actual current of the rear axle motor; —The maximum power that the power battery is allowed to use for driving.

[0026] Further, S300 specifically involves: obtaining the difference between the power consumed by the front and rear axle motors and the product of the maximum power allowed by the power battery for driving and a safety factor. :

[0027]

[0028] in: —The actual speed of the front axle motor; —The actual speed of the rear axle motor; —Safety factor, ∈ (0, 1); —The current efficiency of the front and rear axle motors; —The maximum power that the power battery is allowed to use for driving.

[0029] Further, S100 specifically involves: based on the driver's intention, obtaining the target torque of the front and rear axle motors based on the driver's intention, and obtaining the ratio of the target torque of the front and rear axle motors based on the driver's intention.

[0030]

[0031] in: —The ratio of the front and rear axle motors to the target torque based on the driver's intention; —The front axle motor is based on the driver's intended target torque; — The rear axle motor is based on the driver's intended target torque.

[0032] According to a second aspect of the present invention, a dual-axle motor vehicle torque limiting system is provided, which applies the above-described method and includes:

[0033] The intention-torque conversion module is used to obtain the ratio of the target torque of the front and rear axle motors based on the driver's intention.

[0034] The drive power determination module is used to obtain the maximum power that the power battery can be used for driving based on the vehicle's real-time operating current, voltage, and power.

[0035] The power difference acquisition module obtains the difference between the power consumed by the front and rear axle motors and the product of the maximum power allowed by the power battery for driving and a safety factor. ;

[0036] Torque limiting module, used for based Adjust the torque of the front and rear axle motors.

[0037] According to a third aspect of the invention, a dual-axle electric motor vehicle is provided, employing the aforementioned system for torque limiting.

[0038] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects:

[0039] 1. The torque limiting method of the present invention limits the torque of the front and rear axle motors to ensure that the actual discharge power of the power battery does not exceed the real-time maximum allowable discharge power of the power battery, thereby improving the safety of the system and avoiding damage to the power battery;

[0040] 2. In the torque limiting method of the present invention, when the power battery is not allowed to be used, that is, when the maximum power of the power battery allowed to be used for driving is 0, the driving torque of the front and rear axle motors is simultaneously and synchronously output to 0, and there will be no abnormal torque state where one motor drives and the other motor brakes, thus ensuring the safety of vehicle driving. Attached Figure Description

[0041] Figure 1 This is a flowchart of a method for limiting the torque of a dual-axle motor in an automobile according to the present invention;

[0042] Figure 2 This is a flowchart illustrating the process of adjusting the torque of the front and rear axle motors based on power difference, as described in this invention. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0044] like Figure 1 As shown, the present invention provides a method for limiting the torque of a dual-axle motor vehicle, comprising the following steps:

[0045] S100 obtains the ratio of the target torque of the front and rear axle motors based on the driver's intention.

[0046] The S200 obtains the maximum power that the power battery is allowed to use for driving based on the vehicle's real-time operating current, voltage, and power.

[0047] The S300 obtains the difference between the power consumed by the front and rear axle motors and the product of the maximum power allowed by the power battery for driving and a safety factor. ;

[0048] S400 based on Adjust the torque of the front and rear axle motors.

[0049] Specifically, S100 includes: obtaining the ratio of the front and rear axle motor torques based on the driver's intended target torque.

[0050]

[0051] in: —The ratio of the front and rear axle motors to the target torque based on the driver's intention; —The front axle motor is based on the driver's intended target torque; — The rear axle motor is based on the driver's intended target torque.

[0052] Specifically, S200 includes: S200 specifically includes:

[0053] S201 calculates the current consumed by the high-voltage accessories based on the actual current of the power battery and the current of the front and rear axle motors.

[0054] S202 calculates the power consumed by the high-voltage accessory based on the current consumed by the high-voltage accessory and the total voltage of the power battery;

[0055] S203 calculates the maximum power that the power battery can be used for driving based on the power consumed by the high-voltage accessory and the real-time maximum allowable discharge power of the power battery:

[0056]

[0057] in: —The maximum allowable discharge power of the power battery in real time; —The total voltage of the power battery; —Actual current of the power battery; —The actual current of the front axle motor; —The actual current of the rear axle motor; —The maximum power that the power battery is allowed to use for driving.

[0058] Specifically, S300 includes: obtaining the difference between the maximum power allowed by the power battery for driving and the power consumed by the current rear axle motor. :

[0059]

[0060] in: —The actual speed of the front axle motor; —The actual speed of the rear axle motor; —Safety factor, ∈ (0, 1), with a priority of 90%; —The current efficiency of the front and rear axle motors;

[0061] The S400 includes:

[0062] S401 when When the torque is less than or equal to zero, the torque of the front and rear axle motors does not decrease. When the value is greater than zero, the torque reduction of the front and rear axle motors is calculated based on their speeds:

[0063]

[0064] --Obtain the difference between the power consumed by the front and rear axle motors and the product of the maximum power allowed by the power battery for driving and the safety factor; —The actual speed of the front axle motor; —The actual speed of the rear axle motor; —The current efficiency of the front and rear axle motors; —The ratio of the front and rear axle motors to the target torque based on the driver's intention;

[0065] S402 obtains the target torque of the front and rear axle motors based on the reduced torque of the front and rear axles and the target torque of the front and rear axle motors based on the driver's intention:

[0066]

[0067] in, —Target torque of the front axle motor; —Target torque of the rear axle motor; —The ratio of the front and rear axle motors to the target torque based on the driver's intention; —The front axle motor is based on the driver's intended target torque; — The rear axle motor is based on the driver's intended target torque.

[0068] The sum of the electrical power consumed by the target torque of the front and rear axle motors is less than the maximum power that the power battery is allowed to use for driving, which avoids over-discharge of the power battery, improves the safety of the system, and prevents damage to the power battery.

[0069]

[0070]

[0071]

[0072]

[0073] , It can be transformed into:

[0074]

[0075]

[0076]

[0077] when When equal to 0, The calculation is as follows:

[0078]

[0079]

[0080]

[0081]

[0082] when When equal to 0, , Both are zero, thus avoiding the safety hazard of one motor being used for braking and another for driving.

[0083]

[0084] The implementation of the method of this invention is based on programmed processing through a device with central processing unit functionality. Therefore, in practical engineering, the technical solutions and functions of the various embodiments of this invention can be encapsulated into various modules. Based on this reality, and building upon the above embodiments, this invention provides a dual-axle electric motor vehicle torque limiting system for executing the aforementioned dual-axle electric motor vehicle torque limiting method. It includes:

[0085] The intention-torque conversion module is used to obtain the ratio of the target torque of the front and rear axle motors based on the driver's intention.

[0086] The drive power determination module is used to obtain the maximum power that the power battery can be used for driving based on the vehicle's real-time operating current, voltage, and power.

[0087] The power difference acquisition module obtains the difference between the power consumed by the front and rear axle motors and the product of the maximum power allowed by the power battery for driving and a safety factor. ;

[0088] Torque limiting module, used for based Adjust the torque of the front and rear axle motors.

[0089] It should be noted that the system provided by this invention can be used not only to implement the methods in the above-described method embodiments, but also to implement other methods provided by this invention. The only difference is the setting of corresponding functional modules. Its principle is basically the same as that of the above-described system embodiments provided by this invention. As long as those skilled in the art can improve the system in the above-described system embodiments by referring to the specific technical solutions in other method embodiments, combining technical features to obtain corresponding technical means and technical solutions composed of these technical means, while ensuring the practicality of the technical solutions, thereby obtaining corresponding system-like embodiments for implementing the methods in other method-like embodiments.

[0090] Based on the above embodiments, the present invention also provides a dual-axle electric motor vehicle that uses the above-described system for torque limiting.

[0091] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for limiting the torque of a dual-axle motor automobile, characterized in that, Includes the following steps: S100 obtains the ratio of the target torque of the front and rear axle motors based on the driver's intention. The S200 obtains the maximum power that the power battery is allowed to use for driving based on the vehicle's real-time operating current, voltage, and power. The S300 obtains the difference between the power consumed by the front and rear axle motors and the product of the maximum power allowed by the power battery for driving and a safety factor. in: —The actual speed of the front axle motor; —The actual speed of the rear axle motor; —Safety factor, ∈ (0, 1); —The current efficiency of the front and rear axle motors; —The maximum power that the power battery is allowed to use for driving; S400 based on Adjust the torque of the front and rear axle motors; The S400 includes: S401 when When the torque is less than or equal to zero, the torque of the front and rear axle motors does not decrease. When the value is greater than zero, the torque reduction of the front and rear axle motors is calculated based on their speeds: --The difference between the power consumed by the front and rear axle motors and the product of the maximum power allowed by the power battery for driving and the safety factor; —The actual speed of the front axle motor; —The actual speed of the rear axle motor; —The current efficiency of the front and rear axle motors; —The ratio of the front and rear axle motors to the target torque based on the driver's intention; S402 obtains the target torque of the front and rear axle motors based on the reduced torque of the front and rear axles and the target torque of the front and rear axle motors based on the driver's intention: in, —Target torque of the front axle motor; —Target torque of the rear axle motor; —The ratio of the front and rear axle motors to the target torque based on the driver's intention; —The front axle motor is based on the driver's intended target torque; —The rear axle motor is based on the driver's intended target torque; when When equal to 0, , All values ​​are zero to prevent one motor from being used as a brake motor to drive another motor. in, —Target torque of the front axle motor; —Target torque of the rear axle motor; —The ratio of the front and rear axle motors to the target torque based on the driver's intention; —The rear axle motor is based on the driver's intended target torque; — Reduce torque on both front and rear axles.

2. The method for limiting the torque of a dual-axle motor vehicle according to claim 1, characterized in that, Specifically, S200 includes: S201 calculates the current consumed by the high-voltage accessories based on the actual current of the power battery and the current of the front and rear axle motors. S202 calculates the power consumed by the high-voltage accessory based on the current consumed by the high-voltage accessory and the total voltage of the power battery; S203 calculates the maximum power that the power battery can be used for driving based on the power consumed by the high-voltage accessory and the real-time maximum allowable discharge power of the power battery: in: —The maximum allowable discharge power of the power battery in real time; —The total voltage of the power battery; —Actual current of the power battery; —The actual current of the front axle motor; —The actual current of the rear axle motor; —The maximum power that the power battery is allowed to use for driving.

3. The method for limiting the torque of a dual-axle motor vehicle according to claim 1, characterized in that, Specifically, S100 involves: based on the driver's intention, obtaining the target torque of the front and rear axle motors based on the driver's intention, and obtaining the ratio of the target torque of the front and rear axle motors based on the driver's intention. in: —The ratio of the front and rear axle motors to the target torque based on the driver's intention; —The front axle motor is based on the driver's intended target torque; — The rear axle motor is based on the driver's intended target torque.

4. A torque limiting system for a dual-axle motor vehicle, characterized in that, The method described in any one of claims 1-3 includes: The intention-torque conversion module is used to obtain the ratio of the target torque of the front and rear axle motors based on the driver's intention. The drive power determination module is used to obtain the maximum power that the power battery can use for driving based on the vehicle's real-time operating current, voltage, and power. The power difference acquisition module acquires the difference between the power consumed by the front and rear axle motors and the product of the maximum power allowed by the power battery for driving and the safety factor. Torque limiting module, used for based Adjust the torque of the front and rear axle motors.

5. A dual-axle electric motor vehicle, characterized in that, Torque limiting is performed using the system described in claim 4.

Images