Double-motor electric driving device and driving method

Abstract

The invention provides a double-motor electric driving device and a driving method.The driving device comprises a gear shifting element, a first motor, a second motor and at least two rows of first planetary gear trains which are arranged on a rack, the first planetary gear trains in the front row are in driving connection with the first motor, and second connectors are arranged on the first planetary gear trains in the rear row; when the gear shifting element is in a first gear, the first combining piece is combined with the second combining piece; the differential mechanism is in driving connection with a third connector, the rear row first planetary gear train is connected with the third connector, and when the gear shifting element is located at the second gear, the first connector is combined with the third connector; the second motor is in driving connection with the differential through the second planetary gear train; the problem that in the related technology, under the high-speed driving working condition, due to the unicity of the driving mode and the inflexible motor torque distribution mode, the use efficiency of the motor is low is solved.

Description

Technical Field

[0001] The present invention relates to the field of motor drive technology, and in particular to a dual-motor electric drive device and a drive method. Background Art

[0002] With the increasing awareness of global environmental protection and the energy crisis, new energy vehicles, especially electric vehicles, have become the mainstream direction of the development of the automotive industry. As a core component of electric vehicles, the electric drive axle plays a key role in transmitting power from the power source to the wheel end. The quality of its performance is directly related to the vehicle's power performance, energy efficiency level and driving comfort. The electric drive axle usually includes multiple important components such as motors, reducers, motor controllers and differentials. The efficient integration and coordinated work of these components make the electric drive axle a key technology to improve the performance of electric vehicles.

[0003] However, the traditional single-motor electric drive axle design has significant limitations. Due to the high cost of a single high-power motor and its low efficiency under low-load conditions, this type of system often leads to high energy consumption and unsatisfactory power performance of the vehicle. With the continuous advancement of technology, electric drive axles with dual-motor architecture have gradually become a research hotspot. Through the cooperation of two relatively small-power motors, not only the system cost is reduced, but also the motor can be operated more often in the efficient working area through fine speed ratio configuration, thereby significantly improving the vehicle's economy and driving experience.

[0004] In the field of dual-motor electric drive axles, planetary gear mechanisms are widely used to achieve flexible coupling of motors and intelligent distribution of power. Using the planetary gear mechanism, the first motor and the second motor can be connected or disconnected with different components of the gear through the clutch. This dynamic connection method enables the system to smoothly switch between multiple driving modes to cope with different driving conditions and driving needs.

[0005] However, the dual-motor multi-speed electric drive axle system under current technology still has room for improvement. Especially under high-speed driving conditions, due to the single driving mode and inflexible motor torque distribution strategy, the power utilization efficiency of the motor cannot reach the optimal state, which not only leads to additional energy consumption, but also affects the economy and overall performance of electric vehicles. Summary of the invention

[0006] The main purpose of the present invention is to provide a dual-motor electric drive device and a drive method to solve the problem in the related art that under high-speed driving conditions, the motor utilization efficiency is low due to the singleness of the drive mode and the inflexible motor torque distribution method.

[0007] In order to achieve the above objective, according to one aspect of the present invention, a dual-motor electric drive device and a drive method are provided.

[0008] First, the present application provides a dual-motor electric drive device, comprising: a shift mechanism, comprising a first coupling member rotatably disposed on a frame and a shift element movably disposed on the frame, the shift element having a first gear position and a second gear position;

[0009] The first motor and the second motor are both arranged on the frame;

[0010] At least two rows of first planetary gear trains are both arranged on the frame, and the at least two rows of first planetary gear trains include a front row first planetary gear train and a rear row first planetary gear train that are connected, the front row first planetary gear train is drivingly connected to the first motor, and the rear row first planetary gear train is provided with a second combining member, and when the shift element is in the first gear position, the first combining member is combined with the second combining member;

[0011] A differential is arranged on the frame, a third coupling member is drivingly connected to the differential, the first rear planetary gear train is connected to the third coupling member, and when the shift element is in the second gear position, the first coupling member is coupled to the third coupling member;

[0012] The second planetary gear train is arranged on the frame, and the second motor is drivingly connected to the differential through the second planetary gear train.

[0013] Further, the second motor is drivingly connected to the third sun gear of the second planetary gear train, and the third planet carrier shaft of the second planetary gear train is drivingly connected to the differential; and / or,

[0014] The first combining member is a first combining gear, the second combining member is a second combining gear, and the third combining member is a third combining gear; and / or,

[0015] The second combining member and the third combining member are coaxially arranged.

[0016] According to another aspect of the present invention, a dual-motor electric driving method is provided, which is applicable to the dual-motor electric driving device described above, and the dual-motor electric driving method comprises:

[0017] During the operation of the target vehicle, a target vehicle speed and a target torque of the target vehicle within a predetermined range are obtained, wherein the target torque is the sum of the torques of the first motor and the second motor;

[0018] In the pre-examination curve database, a linear curve that satisfies the functional relationship between the target vehicle speed and the target torque is searched;

[0019] According to the correspondence between the linear curve of the functional relationship and the driving mode, the driving mode corresponding to the target vehicle speed and the target torque is obtained and marked to obtain the target driving mode;

[0020] Determining a target total speed and a target total efficiency of the first motor and the second motor according to the target vehicle speed;

[0021] When it is determined that the real-time speed of the target vehicle is the target vehicle speed and the sum of the real-time rotation speeds of the first motor and the second motor is the target total rotation speed, the operation efficiency of the first motor and the second motor is controlled to switch to the target total efficiency, and the target vehicle is driven to operate in the target driving mode;

[0022] Among them, the driving mode includes a single-machine driving mode and a multi-machine driving mode. The single-machine driving mode is a mode of driving with any gear of the transmission connected by the first motor or the second motor, and the multi-machine driving mode is a mode of driving with a combination of any gear of the transmission connected by the first motor and any gear of the transmission connected by the second motor.

[0023] Furthermore, the step of searching the pre-examination curve database for a linear curve that satisfies the functional relationship between the target vehicle speed and the target torque includes:

[0024] Constructing a preset curve database, the preset curve database includes first functional relationship linear curves corresponding to various first sub-modes in the single-machine driving mode, and second functional relationship linear curves corresponding to various second sub-modes in the multi-machine driving mode;

[0025] Taking the target vehicle speed as the first search target, traversing the preset curve database to determine the initial function relationship linear curve to form an initial function relationship linear curve library;

[0026] The target torque is used as the second search target, and the initial functional relationship linear curve library is traversed to determine the functional relationship linear curve.

[0027] Furthermore, the step of constructing a preset curve database includes:

[0028] Acquire a historical characteristic parameter database, the historical characteristic parameter database including a plurality of first historical vehicle speeds of the target vehicle when the target vehicle is in a single-machine driving mode, and a first historical torque corresponding to each first historical vehicle speed, the first historical torque being the torque of the first motor or the second motor, and the historical characteristic parameter database also including a plurality of second historical vehicle speeds of the target vehicle when the target vehicle is in a multi-machine driving mode, and a second historical torque corresponding to each second historical vehicle speed, the second historical torque being the sum of the torques of the first motor and the second motor;

[0029] According to a plurality of first historical vehicle speeds and first historical torques corresponding to the first historical vehicle speeds, first functional relationship linear curves corresponding to the first sub-modes in the single-machine driving mode are obtained;

[0030] According to the plurality of second historical vehicle speeds and the second historical torques corresponding to the respective second historical vehicle speeds, second functional relationship linear curves respectively corresponding to the respective second sub-modes in the multi-machine driving mode are obtained.

[0031] Furthermore, the step of obtaining first functional relationship linear curves corresponding to each first sub-mode in the single-machine driving mode according to a plurality of first historical vehicle speeds and first historical torques corresponding to each first historical vehicle speed includes:

[0032] A first rectangular coordinate system is constructed with the first historical vehicle speed as the X-axis and the first historical torque as the Y-axis;

[0033] forming a plurality of first coordinate points in a first rectangular coordinate system according to a plurality of first historical vehicle speeds and a first historical torque corresponding to each first historical vehicle speed;

[0034] Marking the first coordinate points in the first historical torque of the plurality of first coordinate points that are greater than or equal to the first set torque and less than or equal to the second set torque as a first group of coordinate points, and marking the first coordinate points in the first historical torque of the plurality of first coordinate points that are less than the first set torque as a second group of coordinate points;

[0035] Along the X-axis direction, all coordinate points in the first group of coordinate points are connected in sequence to obtain a first functional relationship linear curve corresponding to the first motor or the second motor corresponding to the single-machine driving mode when the transmission connected by the first motor is in the first gear, which is marked as the first single-machine functional relationship linear curve;

[0036] Along the X-axis direction, all coordinate points in the second group of coordinate points are connected in sequence to obtain the first functional relationship linear curve corresponding to the single-machine drive mode when the transmission connected to the first motor or the second motor is in the second gear, which is marked as the second single-machine functional relationship linear curve.

[0037] Further, the step of obtaining the second functional relationship linear curves corresponding to each second sub-mode in the multi-machine driving mode according to the plurality of second historical vehicle speeds and the second historical torques corresponding to each second historical vehicle speed includes:

[0038] A second rectangular coordinate system is constructed with the second historical vehicle speed as the X-axis and the second historical torque as the Y-axis;

[0039] According to the plurality of second historical vehicle speeds and the second historical torques corresponding to the respective second historical vehicle speeds, a plurality of second coordinate points are formed in a second rectangular coordinate system;

[0040] Mark the second coordinate points in the second historical torque among the plurality of second coordinate points that are less than the third set torque as a third group of coordinate points, mark the second coordinate points that are greater than or equal to the third set torque and less than or equal to the fourth set torque as a fourth group of coordinate points, and mark the second coordinate points that are greater than the fourth set torque and less than or equal to the fifth set torque as a fifth group of coordinate points;

[0041] Along the X-axis direction, all coordinate points in the third group of coordinate points are connected in sequence to obtain a second functional relationship linear curve corresponding to the multi-machine driving mode when the first motor is in the second gear and the second motor is in the second gear, which is marked as a first multi-machine functional relationship linear curve;

[0042] Along the X-axis direction, all coordinate points in the fourth group of coordinate points are connected in sequence to obtain a second functional relationship linear curve corresponding to the multi-machine driving mode when the transmission connected by the first motor driving is in the first gear and the transmission connected by the second motor driving is in the second gear, which is marked as the second multi-machine functional relationship linear curve;

[0043] Along the X-axis direction, all coordinate points in the fifth group of coordinate points are connected in sequence to obtain the second functional relationship linear curve corresponding to the multi-machine drive mode when the transmission connected by the first motor drive is in first gear and the transmission connected by the second motor drive is in first gear, which is marked as the third multi-machine functional relationship linear curve.

[0044] Furthermore, the driving mode corresponding to the target vehicle speed and the target torque is obtained and marked, and the step of obtaining the target driving mode includes:

[0045] If it is determined that the coordinate points of the target vehicle speed and the target torque in the first rectangular coordinate system are only within the area enclosed by the first single-machine function relationship linear curve and the second single-machine function relationship linear curve, the driving mode corresponding to the first single-machine function relationship linear curve is used as the target driving mode.

[0046] Furthermore, the preset curve database includes a first single-machine function relationship linear curve, a second single-machine function relationship linear curve, a third multi-machine function relationship linear curve and a second multi-machine function relationship linear curve, and the drive mode corresponding to the target vehicle speed and the target torque is obtained and marked, and the step of obtaining the target drive mode includes:

[0047] When it is determined that the target vehicle speed and the target torque are within the region enclosed by the first single-machine function relationship linear curve and the second single-machine function relationship linear curve, and when it is determined that the target vehicle speed and the target torque are within the region enclosed by the third multi-machine function relationship linear curve and the second multi-machine function relationship linear curve, the vehicle operation parameters are obtained, and the vehicle operation parameters at least include the real-time vehicle speed and the rotation speeds of the first motor and the second motor;

[0048] Calculate a first energy consumption corresponding to a first single-machine function relationship linear curve and a second energy consumption corresponding to a third multi-machine function relationship linear curve according to vehicle operating parameters, target vehicle speed and target torque;

[0049] The driving mode corresponding to the minimum value between the first energy consumption and the second energy consumption is used as the target driving mode.

[0050] Further, a first rectangular coordinate system is constructed with the first historical vehicle speed as the X-axis and the first historical torque as the Y-axis, and a second rectangular coordinate system is constructed with the second historical vehicle speed as the X-axis and the second historical torque as the Y-axis, and a drive mode corresponding to the target vehicle speed and the target torque is obtained and marked, and a step of obtaining a target drive mode includes:

[0051] When it is determined that the coordinate points of the target vehicle speed and the target torque in the first rectangular coordinate system are within the region enclosed by the second single-machine function relationship linear curve and the X-axis of the first rectangular coordinate system, and when it is determined that the coordinate points of the target vehicle speed and the target torque in the second rectangular coordinate system are within the region enclosed by the second multi-machine function relationship linear curve and the X-axis of the second rectangular coordinate system, the vehicle operating parameters are obtained, and the vehicle operating parameters at least include the real-time vehicle speed and the rotational speeds of the first motor and the second motor;

[0052] According to the vehicle operating parameters, the target vehicle speed and the target torque, respectively calculate the third energy consumption corresponding to the second single-machine function relationship linear curve, the fourth energy consumption corresponding to the second multi-machine function relationship linear curve and the fifth energy consumption corresponding to the first multi-machine function relationship linear curve;

[0053] A driving mode corresponding to a minimum value among the third energy consumption, the fourth energy consumption and the fifth energy consumption is used as a target driving mode.

[0054] Further, after the step of taking the driving mode corresponding to the minimum value of the first energy consumption and the second energy consumption as the target driving mode, the method further includes:

[0055] When it is determined that the second energy consumption is less than the first energy consumption, obtaining the maximum torque of the first motor;

[0056] dividing the maximum torque into a plurality of first partial torques at set torque intervals;

[0057] Controlling the rotation speed of the first motor to remain unchanged, and calculating the first power consumption of the first motor corresponding to each first partial torque;

[0058] Determine the torque corresponding to the minimum value among the plurality of first power consumptions as the current torque of the first motor;

[0059] determining a current torque of the second motor according to the target torque and the current torque of the first motor;

[0060] A first torque request is sent to a controller of the first electric machine to cause the first electric machine to respond and operate at the first electric machine's current torque, and a second torque request is sent to a controller of the second electric machine to cause the second electric machine to respond and operate at the second electric machine's current torque.

[0061] Further, the step of determining the current torque of the second motor according to the target torque and the current torque of the first motor includes:

[0062] calculating a torque difference between the target torque and the current torque of the first motor;

[0063] Controlling the rotation speed of the second motor to remain unchanged, and calculating the second power consumption of the second motor corresponding to all first partial torques that are smaller than the torque difference among the plurality of first partial torques;

[0064] Determine the torque corresponding to the minimum value of the multiple second power consumptions as the current torque of the second motor.

[0065] By applying the technical solution of the present invention and configuring a multi-gear planetary gear system for the first motor, the most suitable gear can be intelligently selected under different working conditions to ensure that the motor operates in a high-efficiency area, reduce energy waste, and thus significantly improve the economy of the system.

[0066] The second motor is equipped with a fixed-ratio reduction gearbox, which can respond quickly when starting or overtaking, increase wheel-end torque, and ensure that the vehicle has sufficient power in any situation.

[0067] The dual-motor electric drive device of the present application can not only realize the flexible switching between single-motor drive and dual-motor drive, but also select gears according to the vehicle driving conditions to achieve the optimal torque distribution of power coupling, ensuring that the optimal energy utilization effect is achieved while meeting the power requirements.

[0068] The second coupling member and the third coupling member are coaxially arranged, which simplifies the power transmission path, reduces the complexity of the control system, and makes the implementation of the driving strategy easier.

[0069] The use of a fixed-speed ratio reduction gearbox for the second motor not only reduces system costs, but also optimizes the layout space of the drive axle, which is beneficial to the compactness and lightweight of the overall vehicle design.

[0070] To sum up, the dual-motor multi-speed electric drive system proposed in this embodiment, through precise shifting mechanism design and innovative driving strategy, effectively overcomes the problems of motor power waste and single driving strategy in the prior art, realizes high efficiency, economy and flexibility of power transmission, and has significant technical effects on improving the overall performance of new energy commercial vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0072] Figure 1 A schematic diagram of the architecture of an electric drive device according to an embodiment of the present invention is shown.

[0073] The above drawings include the following reference numerals:

[0074] 1. Frame; 2. First coupling member; 3. Shift element; 4. First motor; 5. Second motor; 6. First sun gear; 7. First planetary carrier shaft; 8. Second sun gear; 9. Second planetary carrier shaft; 10. Second coupling member; 11. Differential; 12. First reducer; 13. Second reducer; 14. Third coupling member; 15. Ring gear shaft; 16. Third planetary carrier shaft. DETAILED DESCRIPTION

[0075] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0076] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0077] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present invention. Meanwhile, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0078] With the increasing awareness of global environmental protection and the energy crisis, new energy vehicles, especially electric vehicles, have become the mainstream direction of the development of the automotive industry. As a core component of electric vehicles, the electric drive axle plays a key role in transmitting power from the power source to the wheel end. The quality of its performance is directly related to the vehicle's power performance, energy efficiency level and driving comfort. The electric drive axle usually includes multiple important components such as motors, reducers, motor controllers and differentials. The efficient integration and coordinated work of these components make the electric drive axle a key technology to improve the performance of electric vehicles.

[0079] However, the traditional single-motor electric drive axle design has significant limitations. Due to the high cost of a single high-power motor and its low efficiency under low-load conditions, this type of system often leads to high energy consumption and unsatisfactory power performance of the vehicle. With the continuous advancement of technology, electric drive axles with dual-motor architecture have gradually become a research hotspot. Through the cooperation of two relatively small-power motors, not only the system cost is reduced, but also the motor can be operated more often in the efficient working area through fine speed ratio configuration, thereby significantly improving the vehicle's economy and driving experience.

[0080] In the field of dual-motor electric drive axles, planetary gear mechanisms are widely used to achieve flexible coupling of motors and intelligent distribution of power. Using the planetary gear mechanism, the first motor and the second motor can be connected or disconnected with different components of the gear through the clutch. This dynamic connection method enables the system to smoothly switch between multiple driving modes to cope with different driving conditions and driving needs.

[0081] However, the dual-motor multi-speed electric drive axle system under current technology still has room for improvement. Especially under high-speed driving conditions, due to the single driving mode and inflexible motor torque distribution strategy, the power utilization efficiency of the motor cannot reach the optimal state, which not only leads to additional energy consumption, but also affects the economy and overall performance of electric vehicles.

[0082] The main purpose of the present invention is to provide a dual-motor electric drive device and a drive method to solve the problem in the related art that under high-speed driving conditions, the motor utilization efficiency is low due to the singleness of the drive mode and the inflexible motor torque distribution method.

[0083] First, the present application provides a dual-motor electric drive device, such as Figure 1As shown, the dual-motor electric drive device provided in the present application includes a shift mechanism, the shift mechanism includes a first coupling member 2 rotatably arranged on a frame 1, and a shift element 3 movably arranged on the frame 1, the shift element 3 has a first gear position and a second gear position, a first motor 4 and a second motor 5 are also arranged on the frame 1, and at least two rows of first planetary gear trains are also arranged on the frame 1, the at least two rows of the first planetary gear trains include a front row first planetary gear train and a rear row first planetary gear train, the first sun gear 6 of the front row first planetary gear train is drivingly connected to the first motor 4, the first planetary wheel carrier shaft 7 of the front row first planetary gear train is drivingly connected to the second sun gear 8 of the rear row first planetary gear train, and the second coupling member 10 is arranged on the second planetary wheel carrier shaft 9;

[0084] The differential 11, the first reducer 12 and the second reducer 13 are all arranged on the frame 1. The first reducer 12 and the second reducer 13 are respectively connected to the first reducer 12 and the second reducer 13 on both sides of the differential 11. The differential 11 is drivingly connected with a third coupling member 14. The ring gear shaft 15 of the rear first planetary gear train in the different first planetary gear trains is connected to the third coupling member 14. The frame 1 is also provided with a second planetary gear train, and the second motor 5 is connected to the differential 11 through the second planetary gear train.

[0085] Among them, the second motor 5 is drivingly connected to the third sun gear in the second planetary gear system, the third planetary carrier shaft 16 of the second planetary gear system is drivingly connected to the differential 11, the first coupling component 2 is the first coupling gear, the second coupling component 10 is the second coupling gear, the third coupling component 14 is the third coupling gear, and the second coupling component 10 and the third coupling component 14 are coaxially arranged.

[0086] The shift mechanism includes a first coupling member 2 and a shift element 3, wherein the first coupling member 2 is rotatably arranged on the frame 1, and the shift element 3 is movably arranged on the frame 1, and has a first gear and a second gear, and can switch different transmission paths by moving. The first motor 4 and the second motor 5 are respectively configured with at least two rows of first planetary gear trains and one row of second planetary gear trains, the first sun gear 6 of the front row first planetary gear train is directly connected to the first motor 4 by driving, and the first planetary gear carrier shaft 7 of the front row first planetary gear train is connected to the second sun gear 8 of the rear row first planetary gear train by driving, so as to realize the multi-gear shifting of the first motor 4. The second motor 5 is connected to the differential 11 through the second planetary gear train, wherein the second motor 5 is connected to the third sun gear of the second planetary gear train by driving, and the third planetary carrier shaft 16 of the second planetary gear train is directly connected to the differential 11 by driving, so as to ensure that the second motor operates efficiently at a fixed speed ratio.

[0087] The differential 11, the first reducer 12 and the second reducer 13 are all arranged on the frame 1. The two sides of the differential 11 are respectively connected to the first reducer 12 and the second reducer 13. The power is evenly distributed to the driving wheels on both sides of the vehicle through the differential 11. The third coupling member 14 is connected to the ring gear shaft 15 of the rear planetary gear system in different first planetary gear systems to ensure that the power can be effectively transmitted from the first motor 4 to the differential 11 after shifting.

[0088] By configuring a multi-gear planetary gear system for the first motor 4, the most suitable gear can be intelligently selected under different working conditions to ensure that the motor operates in a high-efficiency area, reduce energy waste, and thus significantly improve the economy of the system.

[0089] The second motor 5 is equipped with a fixed speed ratio reduction box, which can respond quickly under starting or overtaking conditions, increase wheel-end torque, and ensure that the vehicle can obtain sufficient power in any situation.

[0090] The dual-motor electric drive device of the present application can not only realize the flexible switching between single-motor drive and dual-motor drive, but also select gears according to the vehicle driving conditions to achieve the optimal torque distribution of power coupling, ensuring that the optimal energy utilization effect is achieved while meeting the power requirements.

[0091] The second coupling member 10 and the third coupling member 14 are coaxially arranged, which simplifies the power transmission path, reduces the complexity of the control system, and makes the implementation of the driving strategy easier.

[0092] The use of a fixed speed ratio reduction gearbox for the second motor 5 not only reduces the system cost, but also optimizes the layout space of the drive axle, which is beneficial to the compactness and lightweight of the overall vehicle design.

[0093] To sum up, the dual-motor multi-speed electric drive system proposed in this embodiment, through precise shifting mechanism design and innovative driving strategy, effectively overcomes the problems of motor power waste and single driving strategy in the prior art, realizes high efficiency, economy and flexibility of power transmission, and has significant technical effects on improving the overall performance of new energy commercial vehicles.

[0094] The present application also provides a dual-motor electric drive method, which is applicable to the dual-motor electric drive device described above, and the dual-motor electric drive method includes:

[0095] Get the target vehicle speed and target torque:

[0096] During the scheduled travel of the target vehicle, the vehicle operating status is monitored in real time, and data of the target vehicle speed (i.e., the current or expected driving speed of the vehicle) and the target torque (the total torque output by the first motor and the second motor) are collected. These data can be obtained through on-board sensors, such as speed sensors, torque sensors, etc., or can be inferred through driver input (such as accelerator pedal position, driving mode selection, etc.).

[0097] By monitoring the target speed and target torque of the target vehicle, the dual-motor multi-speed electric drive axle architecture of the present invention can quickly calculate and determine the most economical driving mode. It can not only intelligently select single-motor or dual-motor drive, but also in the dual-motor drive mode, according to the target torque (i.e., the sum of the torques of the first motor and the second motor), perform optimal torque distribution to ensure that each motor operates at its most efficient operating point, thereby reducing power consumption and improving energy utilization efficiency.

[0098] Under different working conditions, the electric drive axle of the present invention can achieve mode switching without power interruption, ensuring driving smoothness while avoiding power loss in the traditional gear shifting process. This smooth switching capability is crucial to improving driving experience and overall vehicle performance.

[0099] The present invention adopts an economical shifting rule, which enables the motor to operate at the most appropriate gear according to the change of vehicle speed, thereby meeting the power demand while minimizing energy consumption. This feature is particularly prominent under high-speed driving conditions, which can effectively avoid the waste of motor power and reduce the energy consumption of the entire vehicle.

[0100] Taking into account the various operating conditions that the target vehicle may encounter during the scheduled journey, the drive strategy design of the present invention fully considers the operating conditions, scenarios, minimum energy consumption, motor efficiency MAP and optimal torque distribution of the dual motors, so that the electric drive axle system can flexibly adapt to various driving conditions, whether it is urban congestion, high-speed cruising or complex road conditions, it can maintain excellent performance.

[0101] By simplifying the design of the shift mechanism, the present invention reduces the use of complex planetary gear mechanisms and reduces the overall cost of the system. The dual-motor configuration can further reduce costs through economies of scale, while the motors operate in a high-efficiency region to reduce power consumption.

[0102] Since the present invention can reduce vehicle energy consumption and reduce electricity consumption, it indirectly reduces carbon emissions in the electricity production process, making a positive contribution to environmental protection. In addition, the motor running in the high-efficiency zone also reduces noise and heat emissions, further improving the environmental performance of the vehicle.

[0103] S2. searching a linear curve that satisfies the functional relationship between the target vehicle speed and the target torque in a preliminary examination curve database;

[0104] Specifically, a preset curve database is constructed, wherein the preset curve database includes first functional relationship linear curves corresponding to various first sub-modes in the single-machine driving mode, and second functional relationship linear curves corresponding to various second sub-modes in the multi-machine driving mode;

[0105] The steps of constructing the pre-trial curve database include:

[0106] Obtain a historical characteristic parameter database, wherein the historical characteristic parameter database includes a plurality of first historical vehicle speeds of the target vehicle when the target vehicle is in a single-machine driving mode, and a first historical torque corresponding to each first historical vehicle speed, wherein the first historical torque is the torque of the first motor or the second motor, and the historical characteristic parameter database also includes a plurality of second historical vehicle speeds of the target vehicle when the target vehicle is in a multi-machine driving mode, and a second historical torque corresponding to each second historical vehicle speed, wherein the second historical torque is the sum of the torques of the first motor and the second motor.

[0107] In order to build a preset curve database that can effectively guide the intelligent operation of the dual-motor electric drive axle system, the following steps elaborate on how to extract data from the historical characteristic parameter database, analyze and establish functional relationship linear curves under various drive modes, and provide a decision-making basis for drive mode selection and motor torque distribution under dynamic conditions.

[0108] First, historical data of the target vehicle under different driving environments and working conditions are collected, including key parameters such as vehicle speed and motor torque in single-machine driving mode and multi-machine driving mode. These data can be obtained through the vehicle's driving recorder, on-board sensors, or driver's operation records.

[0109] The collected historical data is cleaned and sorted to ensure the accuracy and completeness of the data. The data is classified according to the driving mode and stored as historical characteristic parameters of the target vehicle in single-machine driving mode and multi-machine driving mode respectively to build a historical characteristic parameter database.

[0110] Single-machine driving mode curve construction: With the first historical vehicle speed as the X-axis and the corresponding first historical torque (i.e., the torque of the first motor or the second motor) as the Y-axis, a first rectangular coordinate system is constructed. In this coordinate system, all the collected combination points of the first historical vehicle speed and the first historical torque are plotted as coordinate points.

[0111] According to the corresponding relationship between the first historical vehicle speed and the first historical torque, a curve is fitted. Each first sub-mode (ie, different gears in the single-machine drive mode) will generate a first functional relationship linear curve, representing the relationship between the motor torque and the vehicle speed in this mode.

[0112] Multi-machine drive mode curve construction: With the second historical vehicle speed as the X-axis and the corresponding second historical torque (i.e. the sum of the torques of the first motor and the second motor) as the Y-axis, a second rectangular coordinate system is constructed, and all collected combination points of the second historical vehicle speed and the second historical torque are plotted as coordinate points.

[0113] As in the single-machine driving mode, a second functional relationship linear curve is generated for each second sub-mode (i.e., different gear combinations in the multi-machine driving mode) according to the corresponding relationship between the second historical vehicle speed and the second historical torque, to ensure that all possible multi-machine driving modes are covered.

[0114] Establishment of preset curve database: Design and establish a preset curve database, and classify and store all the first functional relationship linear curves and second functional relationship linear curves constructed above according to different driving modes and sub-modes.

[0115] To ensure the accuracy and timeliness of the database, a curve update mechanism is designed. The curves in the database are updated regularly or according to specific conditions (such as vehicle maintenance, software upgrades, etc.) to reflect the latest changes and optimization improvements in vehicle performance.

[0116] During the operation of the target vehicle, the system obtains the target vehicle speed and target torque in real time, and compares them with the curves in the preset curve database to determine the optimal driving mode and motor torque distribution strategy.

[0117] As an important decision-making basis for the intelligent drive system, the preset curve database can guide the system to quickly and accurately select the most economical and effective drive mode according to the current working conditions, while achieving smooth gear shifting and torque distribution of the motor in the efficient gear.

[0118] The pre-examination curve database includes functional relationship linear curves of various first sub-modes in the single-machine driving mode and various second sub-modes in the multi-machine driving mode. These curves are based on the data in the historical characteristic parameter database and include the operating status of the target vehicle at different vehicle speeds and torques. By querying the database, the present invention can quickly and accurately find the driving mode that meets the current target vehicle speed and target torque, and achieve the best motor operating state.

[0119] According to the target speed and target torque of the target vehicle, the present invention can find the motor operating point with the lowest energy consumption from the preset curve database. This intelligent matching mechanism ensures that the motor can operate in the high-efficiency zone under any operating conditions, reduces overall energy consumption, and improves energy utilization, which significantly improves the endurance and economy of electric vehicles.

[0120] The linear function relationship curve in the preset curve database not only provides the optimal operating point of the motor under different driving modes, but also guides the smooth transition of the electric drive axle between various modes, avoiding power interruption or impact that may occur during mode switching, and improving driving comfort and safety.

[0121] The establishment of a historical characteristic parameter database enables the electric drive axle system of the present invention to make decisions based on a large amount of historical data. This data-driven intelligent analysis improves the accuracy and reliability of system decisions, can better cope with unknown changes in operating conditions in the future, and enhances the adaptability and flexibility of the vehicle.

[0122] The present invention reduces unnecessary power consumption by optimizing the motor operation state and shifting strategy, thereby reducing the vehicle's operating costs. At the same time, by reducing energy waste, the present invention also helps reduce carbon emissions and other environmental impacts, conforms to the global environmental protection trend, and has significant social and environmental benefits.

[0123] The use of a preset curve database enables the electric drive axle system to adjust the drive mode and motor operating status in real time during vehicle operation, ensuring that the vehicle performance is always in the best state, providing the best driving experience and performance whether driving at low speeds in the city or cruising on the highway.

[0124] According to a plurality of first historical vehicle speeds and first historical torques corresponding to the first historical vehicle speeds, first functional relationship linear curves corresponding to the first sub-modes in the single-machine driving mode are obtained;

[0125] Specifically, a first rectangular coordinate system is constructed with the first historical vehicle speed as the X-axis and the first historical torque as the Y-axis;

[0126] forming a plurality of first coordinate points in a first rectangular coordinate system according to a plurality of first historical vehicle speeds and a first historical torque corresponding to each first historical vehicle speed;

[0127] Marking the first coordinate points in the first historical torque of the plurality of first coordinate points that are greater than or equal to the first set torque and less than or equal to the second set torque as a first group of coordinate points, and marking the first coordinate points in the first historical torque of the plurality of first coordinate points that are less than the first set torque as a second group of coordinate points;

[0128] Along the X-axis direction, all coordinate points in the first group of coordinate points are connected in sequence to obtain a first functional relationship linear curve corresponding to the first motor or the second motor corresponding to the single-machine driving mode when the transmission connected by the first motor is in the first gear, which is marked as the first single-machine functional relationship linear curve;

[0129] Along the X-axis direction, all coordinate points in the second group of coordinate points are connected in sequence to obtain the first functional relationship linear curve corresponding to the single-machine drive mode when the transmission connected to the first motor or the second motor is in the second gear, which is marked as the second single-machine functional relationship linear curve.

[0130] This implementation focuses on constructing a linear curve of the functional relationship between the first motor or the second motor in the single-machine driving mode. These curves will be used to guide the optimization of the driving strategy and the selection of the motor gear to ensure that the motor can operate at the optimal efficiency under different working conditions. The following are the detailed steps:

[0131] The historical data of the target vehicle in actual operation are collected, including the first historical vehicle speed and the first historical torque in the single-machine driving mode, where the historical torques refer to the output torque of any motor (the first motor or the second motor).

[0132] The collected first historical vehicle speed and first historical torque data are preprocessed, including data cleaning and format standardization, to ensure the accuracy and consistency of the data.

[0133] A first rectangular coordinate system is defined, with the first historical vehicle speed as the X-axis and the first historical torque as the Y-axis, and each combination of the first historical vehicle speed and the first historical torque in the historical data is plotted as a coordinate point according to the defined coordinate system.

[0134] According to the size of the torque, the first coordinate points are divided into two groups. The coordinate points with a torque between the first set torque and the second set torque are the first group of coordinate points, marked as "torque working range A"; the coordinate points with a torque less than the first set torque are the second group of coordinate points, marked as "torque working range B".

[0135] In the first rectangular coordinate system, the first set of coordinate points are connected in sequence along the X-axis direction to form a continuous curve. This curve represents the linear relationship between the torque and the vehicle speed of the motor in the first gear, and is marked as the "first single-machine function relationship linear curve".

[0136] Similarly in the first rectangular coordinate system, the second set of coordinate points are connected in sequence along the X-axis direction to form a continuous curve, which represents the linear relationship between the torque of the motor in the second gear and the vehicle speed, and is marked as the "second single-machine function relationship linear curve".

[0137] The established functional relationship linear curve will be used to guide the gear selection and torque distribution of the motor in the single-machine driving mode. When the monitored target vehicle speed and target torque are in the "torque working range A", the system will refer to the "first single-machine functional relationship linear curve" to adjust the gear and torque to ensure that the motor runs in the first gear; when it is in the "torque working range B", it will refer to the "second single-machine functional relationship linear curve" to adjust the motor to run in the second gear.

[0138] The system will monitor the vehicle speed and torque demand in real time, and compare them with the pre-built functional linear curve to decide whether to select the single-machine drive mode under the current working conditions, as well as which motor (first motor or second motor) and which gear (first gear or second gear) to select for driving, so as to achieve the best energy efficiency ratio and driving experience.

[0139] By constructing a first functional relationship linear curve of the first motor or the second motor in the single-machine driving mode, the system can quickly determine the optimal torque that matches the target vehicle speed. This mechanism ensures that the transmission driven by the first motor or the second motor can operate efficiently in both the first gear and the second gear, avoiding energy waste caused by the mismatch between torque and vehicle speed.

[0140] The preset first single machine function relationship linear curve and second single machine function relationship linear curve provide the basis for intelligent gear shifting for the electric drive axle system. When the target torque is between the first set torque and the second set torque, the first gear corresponding to the first single machine function relationship linear curve will be automatically selected for driving; if the target torque is lower than the first set torque, the system will switch to the second gear corresponding to the second single machine function relationship linear curve to achieve a more economical operating mode.

[0141] During the driving process, the current vehicle speed and torque demand can be monitored in real time, and adjustments can be made quickly by querying the preset functional relationship linear curve. This real-time performance optimization capability ensures that the motor always runs in the best state, providing stable and efficient power output at low speeds or high-speed cruising, and improving the driving experience.

[0142] By marking the first and second groups of coordinate points and constructing corresponding linear curves of functional relationships, the present invention can accurately identify and adapt to various working conditions. This working condition adaptability based on historical data enables the system to make more accurate decisions when facing complex and changing driving environments, thereby enhancing the stability and reliability of the system.

[0143] The method of constructing a linear curve of functional relationship simplifies the control logic and avoids complex real-time calculations. The system can find the optimal operating state according to the preset curve by only monitoring the vehicle speed and torque, which reduces the control complexity and improves the system's response speed and control accuracy.

[0144] By improving the operating efficiency of the motor and reducing unnecessary gear shifting, the present invention helps reduce operating costs and energy consumption, thereby reducing carbon emissions and having a positive impact on environmental protection. In addition, the optimized motor operation state also reduces noise and vibration, improving driving comfort.

[0145] According to the plurality of second historical vehicle speeds and the second historical torques corresponding to the respective second historical vehicle speeds, second functional relationship linear curves corresponding to the respective second sub-modes in the multi-machine driving mode are obtained;

[0146] Specifically, a second rectangular coordinate system is constructed with the second historical vehicle speed as the X-axis and the second historical torque as the Y-axis;

[0147] According to the plurality of second historical vehicle speeds and the second historical torques corresponding to the respective second historical vehicle speeds, a plurality of second coordinate points are formed in a second rectangular coordinate system;

[0148] Mark the second coordinate points in the second historical torque among the plurality of second coordinate points that are less than the third set torque as a third group of coordinate points, mark the second coordinate points that are greater than or equal to the third set torque and less than or equal to the fourth set torque as a fourth group of coordinate points, and mark the second coordinate points that are greater than the fourth set torque and less than or equal to the fifth set torque as a fifth group of coordinate points;

[0149] Along the X-axis direction, all coordinate points of the third group of coordinate points are connected in sequence to obtain a second functional relationship linear curve corresponding to the multi-machine driving mode when the transmission connected by the first motor driving is in the second gear and the transmission connected by the second motor driving is in the second gear, which is marked as the first multi-machine functional relationship linear curve;

[0150] Along the X-axis direction, all coordinate points in the fourth group of coordinate points are connected in sequence to obtain a second functional relationship linear curve corresponding to the multi-machine driving mode when the transmission connected by the first motor driving is in the first gear and the transmission connected by the second motor driving is in the second gear, which is marked as the second multi-machine functional relationship linear curve;

[0151] Along the X-axis direction, all the coordinate points in the fifth group of coordinate points are connected in sequence to obtain a second functional relationship linear curve corresponding to the multi-machine driving mode when the transmission connected by the first motor driving is in the first gear and the transmission connected by the second motor driving is in the first gear, which is marked as the third multi-machine functional relationship linear curve;

[0152] Taking the target vehicle speed as the first search target, traversing the preset curve database to determine the initial function relationship linear curve to form an initial function relationship linear curve library;

[0153] The target torque is used as the second search target, and the initial functional relationship linear curve library is traversed to determine the functional relationship linear curve.

[0154] The second historical vehicle speed and the second historical torque data of the target vehicle operating in the multi-motor driving mode are extracted from the historical characteristic parameter database, and these data represent the vehicle performance under the joint action of the dual motors.

[0155] A second rectangular coordinate system is defined, wherein the second historical vehicle speed is used as an X-axis and the second historical torque is used as a Y-axis, and all combined data points of the second historical vehicle speed and the second historical torque are plotted as second coordinate points, distributed in the second rectangular coordinate system.

[0156] Torque range division: According to the size of the torque, the second coordinate points are divided into three groups. The coordinate points with a torque less than the third set torque are marked as the third group of coordinate points, the coordinate points with a torque between the third set torque and the fourth set torque are marked as the fourth group of coordinate points, and the coordinate points with a torque greater than the fourth set torque and not exceeding the fifth set torque are marked as the fifth group of coordinate points. These five set torque values ​​are pre-set according to the performance of the motor and the vehicle operating characteristics.

[0157] The first multi-machine function relationship linear curve: along the X-axis direction, all coordinate points in the third group of coordinate points are connected in sequence using linear interpolation or curve fitting methods to form a curve. This curve represents the multi-machine drive mode characteristics when the transmission connected by the first motor drive is in second gear and the transmission connected by the second motor drive is also in second gear, and is marked as "the first multi-machine function relationship linear curve".

[0158] The second multi-machine function relationship linear curve: Also along the X-axis direction, connect all the coordinate points in the fourth group of coordinate points to form a curve representing the multi-machine drive mode characteristics when the transmission connected by the first motor drive is in first gear and the transmission connected by the second motor drive is in second gear, marked as the "second multi-machine function relationship linear curve".

[0159] The third multi-machine function relationship linear curve: Finally, all the coordinate points in the fifth group of coordinate points are connected along the X-axis direction to obtain a curve representing the multi-machine drive mode characteristics when the transmission connected by the first motor drive is in first gear and the transmission connected by the second motor drive is also in first gear, which is marked as the "third multi-machine function relationship linear curve".

[0160] The constructed "first multi-machine", "second multi-machine" and "third multi-machine" functional relationship linear curves are stored in a preset curve database to form an initial functional relationship linear curve library.

[0161] Taking the target vehicle speed as the search target, traverse the preset curve database, find the initial function relationship linear curve corresponding to the target vehicle speed, and preliminarily determine the possible driving mode.

[0162] Taking the target torque as the search target, the preliminary determined initial function relationship linear curve library is traversed in depth, and the function relationship linear curve that best meets the target torque requirement is determined by comparing the curves, thereby determining the optimal multi-machine driving mode.

[0163] Curve application: By searching the preset curve database for a curve that matches the target vehicle speed and target torque, the system can intelligently select the most economical driving mode, which includes determining the motor's gear and torque distribution strategy to ensure that the motor operates in the high-efficiency zone while meeting the vehicle's power requirements.

[0164] By constructing a second functional relationship linear curve based on historical data, the load of the two motors can be intelligently distributed according to different vehicle speeds and torque requirements. The first multi-machine functional relationship linear curve, the second multi-machine functional relationship linear curve and the third multi-machine functional relationship linear curve correspond to three different gear combinations, ensuring that the most economical and effective motor torque distribution solution can be found under any working condition.

[0165] The system searches and adjusts the initial function relationship linear curve in real time according to the target vehicle speed and target torque. This dynamic working condition matching capability enables the dual-motor system to quickly adapt to different driving conditions, such as urban congestion, high-speed driving or climbing conditions, and provide continuous, stable and efficient power output.

[0166] The linear curve of the functional relationship constructed based on historical vehicle speed and torque data can guide the system to select the mode and motor operating point with the lowest energy consumption while meeting the vehicle performance requirements, achieving an effective balance between performance and economy, which is of great significance for improving the vehicle's endurance and reducing power consumption.

[0167] The present invention simplifies the complexity of real-time decision-making by constructing a linear curve database. Compared with the real-time calculation of the optimal motor torque and gear combination, the system only needs to find the corresponding linear curve according to the target vehicle speed and torque, which greatly reduces the calculation time and resource consumption, and improves the response speed and efficiency of the control system.

[0168] Through precise motor torque distribution and gear selection, the present invention can reduce fluctuations in power output and improve driving smoothness. At the same time, the intelligent adaptability to working conditions can also reduce the impact during gear shifting and improve overall driving comfort.

[0169] Considering the motor torque distribution strategy with the lowest energy consumption not only helps to reduce power consumption and operating costs, but also reduces carbon emissions, which has a positive impact on environmental protection. In addition, by optimizing the motor operating status, unnecessary maintenance and loss are reduced, further improving cost-effectiveness.

[0170] The present invention makes full use of historical data to make decisions, reflecting the concept of data-driven intelligent control. This decision-making model based on big data not only improves the accuracy and reliability of decision-making, but also demonstrates the potential for future development of technology, which can continuously learn and optimize to adapt to more complex and changeable driving environments.

[0171] S3, according to the correspondence between the linear curve of the functional relationship and the driving mode, obtaining the driving mode corresponding to the target vehicle speed and the target torque at the same time and marking them to obtain the target driving mode;

[0172] Specifically, it is determined that the coordinate points of the target vehicle speed and the target torque in the first rectangular coordinate system are only within the area enclosed by the first single-machine function relationship linear curve and the second single-machine function relationship linear curve, and the driving mode corresponding to the first single-machine function relationship linear curve is used as the target driving mode;

[0173] When it is determined that the target vehicle speed and the target torque are within the region enclosed by the first single-machine function relationship linear curve and the second single-machine function relationship linear curve, and when it is determined that the target vehicle speed and the target torque are within the region enclosed by the third multi-machine function relationship linear curve and the second multi-machine function relationship linear curve, the vehicle operation parameters are obtained, and the vehicle operation parameters at least include the real-time vehicle speed and the rotation speeds of the first motor and the second motor;

[0174] Calculate a first energy consumption corresponding to a first single-machine function relationship linear curve and a second energy consumption corresponding to a third multi-machine function relationship linear curve according to vehicle operating parameters, target vehicle speed and target torque;

[0175] taking a driving mode corresponding to a minimum value between the first energy consumption and the second energy consumption as a target driving mode;

[0176] When it is determined that the second energy consumption is less than the first energy consumption, obtaining the maximum torque of the first motor;

[0177] dividing the maximum torque into a plurality of first partial torques at set torque intervals;

[0178] Controlling the rotation speed of the first motor to remain unchanged, and calculating the first power consumption of the first motor corresponding to each first partial torque;

[0179] Determine the torque corresponding to the minimum value among the plurality of first power consumptions as the current torque of the first motor;

[0180] Determine the current torque of the second motor according to the target torque and the current torque of the first motor; specifically: calculate the torque difference between the target torque and the current torque of the first motor;

[0181] Controlling the rotation speed of the second motor to remain unchanged, and calculating the second power consumption of the second motor corresponding to all first partial torques that are smaller than the torque difference among the plurality of first partial torques;

[0182] Determine the torque corresponding to the minimum value among the plurality of second power consumptions as the current torque of the second motor;

[0183] The calculation formula for calculating the first energy consumption is as follows:

[0184]

[0185] Where: E1 represents the first energy consumption;

[0186] T1 represents the real-time torque of the first motor during the operation of the target vehicle;

[0187] T2 represents the real-time torque of the second motor during the operation of the target vehicle;

[0188] n2 represents the real-time speed of the second motor;

[0189] n1 represents the real-time speed of the first motor;

[0190] η0 represents the transmission efficiency of the main reducer;

[0191] η1 represents the efficiency of the first motor;

[0192] η2 represents the efficiency of the second motor;

[0193] Δt represents the simulation duration;

[0194] The calculation formula of the real-time speed n2 of the second motor is as follows:

[0195]

[0196] The calculation formula of the real-time speed n1 of the first motor is as follows:

[0197]

[0198] Where: u1=u2 represents the target vehicle speed, i0 represents the fixed speed ratio of the wheel-side reducer, i1 represents the speed ratio of the transmission connected to the first motor in the single-machine driving mode when it is in the first gear, and r represents the tire radius;

[0199] The calculation formula for the second energy consumption is as follows:

[0200]

[0201] Where: E2 represents the second energy consumption;

[0202] T1 represents the real-time torque of the first motor during the operation of the target vehicle;

[0203] T2 represents the real-time torque of the second motor during the operation of the target vehicle;

[0204] n2 represents the real-time speed of the second motor;

[0205] n1 represents the real-time speed of the first motor;

[0206] η0 represents the transmission efficiency of the main reducer;

[0207] η1 represents the efficiency of the first motor;

[0208] η2 represents the efficiency of the second motor;

[0209] Δt represents the simulation duration;

[0210] The calculation formula of the real-time speed n2 of the second motor is as follows:

[0211]

[0212] The calculation formula of the real-time speed n1 of the first motor is as follows:

[0213]

[0214] Where: u1=u2 represents the target vehicle speed, i0 represents the fixed speed ratio of the wheel-side reducer, i1 represents the speed ratio of the transmission connected to the first motor drive in the single-machine driving mode when it is in the second gear, and r represents the tire radius;

[0215] Sending a first torque request to a controller of the first electric machine to cause the first electric machine to respond and operate at the current torque of the first electric machine, and sending a second torque request to a controller of the second electric machine to cause the second electric machine to respond and operate at the current torque of the second electric machine;

[0216] When it is determined that the coordinate points of the target vehicle speed and the target torque in the first rectangular coordinate system are within the region enclosed by the second single-machine function relationship linear curve and the X-axis of the first rectangular coordinate system, and when it is determined that the coordinate points of the target vehicle speed and the target torque in the second rectangular coordinate system are within the region enclosed by the second multi-machine function relationship linear curve and the X-axis of the second rectangular coordinate system, the vehicle operating parameters are obtained, and the vehicle operating parameters at least include the real-time vehicle speed and the rotational speeds of the first motor and the second motor;

[0217] According to the vehicle operating parameters, the target vehicle speed and the target torque, respectively calculate the third energy consumption corresponding to the second single-machine function relationship linear curve, the fourth energy consumption corresponding to the second multi-machine function relationship linear curve and the fifth energy consumption corresponding to the first multi-machine function relationship linear curve;

[0218] Among them, the calculation formula of the third energy consumption is:

[0219]

[0220] Where: E3 represents the third energy consumption;

[0221] T1 represents the real-time torque of the first motor during the operation of the target vehicle;

[0222] n1 represents the real-time speed of the first motor;

[0223] η1 represents the efficiency of the first motor;

[0224] η2 represents the efficiency of the second motor;

[0225] Δt represents the simulation duration;

[0226] The calculation formula of the real-time speed n1 of the first motor is as follows:

[0227]

[0228] Where: u1=u2=u represents the target vehicle speed, i1 represents the speed ratio of the transmission connected to the first motor in the multi-motor driving mode when it is in the first gear, and r represents the tire radius;

[0229] The calculation formula for the fourth energy consumption is:

[0230]

[0231] Where: E4 represents the fourth energy consumption;

[0232] T1 represents the real-time torque of the first motor during the operation of the target vehicle;

[0233] n1 represents the real-time speed of the first motor;

[0234] η1 represents the efficiency of the first motor;

[0235] η0 represents the transmission efficiency of the main reducer;

[0236] Δt represents the simulation duration;

[0237] The calculation formula of the real-time speed n1 of the first motor is as follows:

[0238]

[0239] Where: u1=u2=u represents the target vehicle speed, i2 represents the speed ratio when the first motor is in the second gear in the multi-motor drive mode, and r represents the tire radius;

[0240] The calculation formula of the fifth energy consumption is:

[0241]

[0242] Where: E5 represents the fifth energy consumption;

[0243] T1 represents the real-time torque of the first motor during the operation of the target vehicle;

[0244] n1 represents the real-time speed of the first motor;

[0245] η2 represents the efficiency of the second motor;

[0246] η0 represents the transmission efficiency of the main reducer;

[0247] Δt represents the simulation duration;

[0248] The calculation formula of the real-time speed n2 of the second motor is as follows:

[0249]

[0250] Where: u1=u2=u represents the target vehicle speed, i0 represents the fixed speed ratio of the wheel reducer, and r represents the tire radius;

[0251] The driving mode corresponding to the minimum value among the third energy consumption, the fourth energy consumption and the fifth energy consumption is taken as the target driving mode.

[0252] In the first rectangular coordinate system, the coordinate point positions of the target vehicle speed and the target torque are determined, and it is judged whether the point is located in the area enclosed by the first single-machine function relationship linear curve and the second single-machine function relationship linear curve. The area represents the applicable range of the single-machine drive mode.

[0253] If the target point is located within the above-mentioned single-machine driving mode area, the driving mode corresponding to the first single-machine function relationship linear curve is directly selected as the target driving mode.

[0254] If the target point is located in both the single-machine driving mode area and the multi-machine driving mode area (ie, the area enclosed by the third multi-machine function relationship linear curve and the second multi-machine function relationship linear curve), the next step of energy consumption calculation is entered.

[0255] Based on the vehicle operating parameters (real-time vehicle speed, motor speed, etc.) and the target vehicle speed and torque, the first energy consumption and the second energy consumption in the first single-machine mode and the third multi-machine mode are calculated respectively.

[0256] The first energy consumption is compared with the second energy consumption, and the driving mode with lower energy consumption is selected as the target driving mode. If the third multi-machine mode has lower energy consumption, the torque distribution step is entered.

[0257] The maximum torque of the first motor is obtained, and divided into a plurality of first partial torques at set torque intervals, the first power consumption caused by each first partial torque at a fixed speed is calculated, and the first partial torque with the minimum power consumption is selected as the current torque of the first motor.

[0258] Based on the target torque and the current torque of the first motor, the torque difference between the two is calculated to determine whether the difference can be satisfied by the second motor at the current speed. If so, the power consumption of the second motor that satisfies the torque difference is calculated, and the torque with the minimum power consumption is selected as the current torque of the second motor.

[0259] The first torque request and the second torque request are sent to the controllers of the first motor and the second motor, so that the two motors respectively operate with the calculated current torques, thereby ensuring the execution of the driving strategy.

[0260] If the target point is located in the second single-machine mode area and the second multi-machine mode area at the same time, and is also located in the first multi-machine mode area at the same time, repeat the above energy consumption calculation steps to compare the third energy consumption in the second single-machine mode, the fourth energy consumption in the second multi-machine mode, and the fifth energy consumption in the first multi-machine mode.

[0261] The driving mode with the lowest energy consumption is selected as the target driving mode, so as to maximize energy efficiency while meeting power requirements.

[0262] The present invention can dynamically select the most economical and effective driving mode between the single-machine driving mode and the multi-machine driving mode according to the real-time monitored target vehicle speed and target torque. This dynamic matching capability ensures that the motor can operate in the best state under any working conditions, improving the vehicle's power performance and energy efficiency.

[0263] By calculating the energy consumption under different driving modes (first to fifth energy consumption), the driving mode with the lowest energy consumption can be selected as the target mode. This energy consumption optimization strategy not only reduces the overall power consumption, but also improves the vehicle's endurance, which is particularly important for long-distance driving and frequent gear shifting.

[0264] In multi-motor drive mode, the system can accurately calculate and distribute the torque of the first motor and the second motor to ensure that the motors operate in the high-efficiency zone. By minimizing the motor power consumption (the first power consumption and the second power consumption), the system achieves optimal torque distribution for the dual motors, avoids power waste, and improves energy utilization.

[0265] Through the intelligent selection of the target driving mode, the present invention can ensure a smooth transition between different driving modes, avoid power interruption or impact during the gear shifting process, and improve driving smoothness and comfort.

[0266] The system builds a linear curve of functional relationships based on historical data, which can provide real-time and accurate decision-making basis. This data-driven decision-making mechanism not only improves the reliability of decision-making, but also demonstrates the adaptability of technology under complex working conditions and its potential for future development.

[0267] The optimized driving mode and torque distribution strategy not only reduces energy consumption and carbon emissions, thus having a positive impact on environmental protection; at the same time, the operation of the motor in the high-efficiency area also reduces maintenance costs and improves overall cost-effectiveness.

[0268] By intelligently selecting driving modes and torque distribution, the present invention can improve the overall dynamic performance of the vehicle, including acceleration performance, grade climbing ability and cruising efficiency, so that the vehicle can maintain optimal performance under different driving conditions.

[0269] S4, determining a target total speed and a target total efficiency of the first motor and the second motor according to the target vehicle speed;

[0270] S5. When it is determined that the real-time speed of the target vehicle is the target speed and the sum of the real-time rotation speeds of the first motor and the second motor is the target total rotation speed, the operating efficiencies of the first motor and the second motor are controlled to switch to the target total efficiency, and the target vehicle is driven to operate in the target driving mode;

[0271] Among them, the driving mode includes a single-machine driving mode and a multi-machine driving mode. The single-machine driving mode is a mode of driving with any gear of the first motor or the second motor, and the multi-machine driving mode is a mode of driving with a combination of any gear of the first motor and any gear of the second motor.

[0272] The target total speed of the first motor and the second motor is calculated based on the target vehicle speed and the transmission ratio of the vehicle (including the tire radius). The total speed should ensure that the two motors have the same speed when coupled, so as to achieve smooth power transmission.

[0273] The target total efficiency is a comprehensive efficiency value based on the target driving mode, taking into account multiple factors such as motor efficiency, transmission efficiency and energy consumption. The target total efficiency under this working condition can be calculated by combining the target vehicle speed and target torque through the functional relationship linear curve in the preset curve database.

[0274] Real-time monitoring of the target vehicle's speed to determine whether the target speed has been reached. Real-time speed monitoring: Simultaneously monitor the real-time speeds of the first motor and the second motor to determine whether the sum of the real-time speeds of the two motors is equal to the target total speed.

[0275] When the real-time speed of the target vehicle is the set target speed, and the sum of the real-time speeds of the two motors is equal to the target total speed, it indicates that the vehicle is in an ideal operating condition and can enter the next stage of operating efficiency adjustment.

[0276] According to the target driving mode, the operating efficiency of the first motor and the second motor is controlled to switch to the target total efficiency. This may include adjusting the working state of the motor, the shifting logic and the torque distribution strategy to ensure that the motor operates in the high efficiency zone.

[0277] After adjusting the operating efficiency of the two motors to the target total efficiency, the target vehicle is driven according to the target driving mode. If the target mode is single-motor driving, the selected motor (the first motor or the second motor) is controlled to operate at the optimal gear position; if the target mode is multi-motor driving, the two motors are controlled to cooperate with each other at the optimal gear position combination.

[0278] During real-time monitoring, if the vehicle operating conditions change, the current target speed and target torque will be re-evaluated, and the single-machine drive mode or multi-machine drive mode will be intelligently selected based on the preset curve database.

[0279] Once the new target driving mode is determined, the operating states of the two motors, including gear selection and torque distribution, will be adjusted quickly to ensure that the vehicle operates at the target total speed and target total efficiency in the new mode.

[0280] The target total speed and target total efficiency of the first and second motors are predicted and determined based on the target vehicle speed, ensuring that the motors operate at the highest efficiency at a specific speed. This optimization can significantly reduce energy consumption and improve energy efficiency, which plays an important role in extending the range of new energy vehicles.

[0281] When the real-time speed of the target vehicle reaches the target speed and the sum of the real-time speeds of the current motors matches the target total speed, the system can intelligently switch the operating efficiency of the first motor and the second motor to the target total efficiency. This instant adjustment capability enables the vehicle to quickly adapt to different working conditions, improving driving flexibility and economy.

[0282] Whether it is a single-machine drive mode or a multi-machine drive mode, the present invention can intelligently select the most appropriate drive mode according to the real-time working conditions. In the single-machine drive mode, the system can select the most efficient motor for driving; while in the multi-machine drive mode, through the combination of different gears, the system can achieve a more refined torque distribution and meet the power requirements of the vehicle in the most economical way.

[0283] By switching the intelligent driving modes and optimizing the motor efficiency, the present invention minimizes the energy consumption while ensuring the vehicle's dynamic performance, thereby finding the best balance between power and economy.

[0284] The intelligent switching mechanism of the present invention can ensure the smoothness of the motor during gear shifting or mode switching, avoid power interruption or impact that may occur during traditional gear shifting, and improve the driving experience.

[0285] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the devices or elements referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention. The directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0286] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0287] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0288] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A dual-motor electric drive device, characterized in that: include: A shift mechanism comprises a first coupling member (2) rotatably arranged on a frame (1) and a shift element (3) movably arranged on the frame (1), wherein the shift element (3) has a first gear position and a second gear position; A first motor (4) and a second motor (5) are both arranged on the frame (1); At least two rows of first planetary gear trains are both arranged on the frame (1), the at least two rows of first planetary gear trains include a front row first planetary gear train and a rear row first planetary gear train that are connected, the front row first planetary gear train is drivingly connected to the first motor (4), and the rear row first planetary gear train is provided with a second coupling member (10), and when the shift element (3) is in a first gear position, the first coupling member (2) is coupled to the second coupling member (10); A differential (11) is arranged on the frame (1); a third coupling member (14) is drivingly connected to the differential (11); the rear first planetary gear train is connected to the third coupling member (14); when the shift element (3) is in the second gear position, the first coupling member (2) is coupled to the third coupling member (14); The second planetary gear train is arranged on the frame (1), and the second motor (5) is drivingly connected to the differential (11) via the second planetary gear train.

2. The dual-motor electric drive device according to claim 1, characterized in that: The second motor (5) is drivingly connected to the third sun gear of the second planetary gear train, and the third planet carrier shaft (16) of the second planetary gear train is drivingly connected to the differential (11); and / or, The first combining member (2) is a first combining gear, the second combining member (10) is a second combining gear, and the third combining member (14) is a third combining gear; and / or, The second combining member (10) and the third combining member (14) are coaxially arranged.

3. A dual-motor electric drive method, characterized in that: The dual-motor electric drive method is applicable to the dual-motor electric drive device according to claim 1 or 2, and the dual-motor electric drive method comprises: During the operation of the target vehicle, a target vehicle speed and a target torque of the target vehicle within a predetermined range are obtained, wherein the target torque is the sum of the torques of the first motor and the second motor; Searching a pre-examination curve database for a linear curve that satisfies a functional relationship between the target vehicle speed and the target torque; According to the correspondence between the linear curve of the functional relationship and the driving mode, a driving mode corresponding to the target vehicle speed and the target torque is obtained and marked to obtain a target driving mode; determining a target total speed of the first motor and the second motor according to the target vehicle speed; When it is determined that the real-time speed of the target vehicle is the target vehicle speed and the sum of the real-time rotation speeds of the first motor and the second motor is the target total rotation speed, the target vehicle is driven to run in the target driving mode; Among them, the driving mode includes a single-machine driving mode and a multi-machine driving mode. The single-machine driving mode is a mode of driving with any gear of the transmission connected by the first motor or the second motor, and the multi-machine driving mode is a mode of driving with a combination of any gear of the transmission connected by the first motor and any gear of the transmission connected by the second motor.

4. The dual-motor electric driving method according to claim 3, characterized in that: The step of searching the pre-examination curve database for a linear curve that satisfies the functional relationship between the target vehicle speed and the target torque includes: Constructing a preset curve database, wherein the preset curve database includes first functional relationship linear curves corresponding to various first sub-modes in the single-machine driving mode, and second functional relationship linear curves corresponding to various second sub-modes in the multi-machine driving mode; Taking the target vehicle speed as the first search target, traversing the preset curve database to determine the initial function relationship linear curve to form an initial function relationship linear curve library; The target torque is used as a second search target, and the initial functional relationship linear curve library is traversed to determine the functional relationship linear curve.

5. The dual-motor electric driving method according to claim 4, characterized in that: The step of constructing the preset curve database includes: Acquire a historical characteristic parameter database, wherein the historical characteristic parameter database includes a plurality of first historical vehicle speeds of the target vehicle when the target vehicle is in the single-machine driving mode, and a first historical torque corresponding to each of the first historical vehicle speeds, wherein the first historical torque is a torque of the first motor or the second motor, and the historical characteristic parameter database also includes a plurality of second historical vehicle speeds of the target vehicle when the target vehicle is in the multi-machine driving mode, and a second historical torque corresponding to each of the second historical vehicle speeds, wherein the second historical torque is a sum of the torques of the first motor and the second motor; Obtaining the first functional relationship linear curves respectively corresponding to the first sub-modes in the single-machine driving mode according to the plurality of the first historical vehicle speeds and the first historical torques corresponding to the first historical vehicle speeds; The second functional relationship linear curves corresponding to each of the second sub-modes in the multi-machine driving mode are obtained according to the plurality of second historical vehicle speeds and the second historical torques corresponding to each of the second historical vehicle speeds.

6. The dual-motor electric driving method according to claim 5, characterized in that: The step of obtaining the first functional relationship linear curves respectively corresponding to each of the first sub-modes in the single-machine driving mode according to the plurality of the first historical vehicle speeds and the first historical torques corresponding to the first historical vehicle speeds comprises: Constructing a first rectangular coordinate system with the first historical vehicle speed as an X-axis and the first historical torque as a Y-axis; forming a plurality of first coordinate points in the first rectangular coordinate system according to a plurality of the first historical vehicle speeds and the first historical torques corresponding to the respective first historical vehicle speeds; Marking the first coordinate points in the first historical torque of the plurality of first coordinate points that are greater than or equal to the first set torque and less than or equal to the second set torque as a first group of coordinate points, and marking the first coordinate points in the first historical torque of the plurality of first coordinate points that are less than the first set torque as a second group of coordinate points; Along the X-axis direction, all coordinate points in the first group of coordinate points are sequentially connected to obtain the first functional relationship linear curve corresponding to the first motor or the second motor corresponding to the single-machine driving mode when the transmission connected by the first motor is in the first gear, which is marked as the first single-machine functional relationship linear curve; Along the X-axis direction, all coordinate points in the second group of coordinate points are connected in sequence to obtain the first functional relationship linear curve corresponding to the first motor corresponding to the single-machine drive mode or the second motor driving the connected transmission in the second gear position, which is marked as the second single-machine functional relationship linear curve.

7. The dual-motor electric driving method according to claim 6, characterized in that: The step of obtaining the second functional relationship linear curves respectively corresponding to each of the second sub-modes in the multi-machine driving mode according to the plurality of second historical vehicle speeds and the second historical torques corresponding to each of the second historical vehicle speeds comprises: Constructing a second rectangular coordinate system with the second historical vehicle speed as an X-axis and the second historical torque as a Y-axis; forming a plurality of second coordinate points in the second rectangular coordinate system according to the plurality of second historical vehicle speeds and the second historical torques corresponding to the respective second historical vehicle speeds; Mark the second coordinate points whose second historical torque is less than the third set torque among the plurality of second coordinate points as a third group of coordinate points, mark the second coordinate points whose second historical torque is greater than or equal to the third set torque and less than or equal to the fourth set torque as a fourth group of coordinate points, and mark the second coordinate points whose second historical torque is greater than the fourth set torque and less than or equal to the fifth set torque as a fifth group of coordinate points; Along the X-axis direction, all the coordinate points in the third group of coordinate points are sequentially connected to obtain the second functional relationship linear curve corresponding to the multi-machine driving mode when the transmission connected by the first motor driving is in the second gear and the transmission connected by the second motor driving is in the second gear, which is marked as the first multi-machine functional relationship linear curve; Along the X-axis direction, all the coordinate points in the fourth group of coordinate points are sequentially connected to obtain the second functional relationship linear curve corresponding to the multi-machine driving mode when the transmission connected by the first motor driving is in the first gear and the transmission connected by the second motor driving is in the second gear, which is marked as the second multi-machine functional relationship linear curve; Along the X-axis direction, all coordinate points in the fifth group of coordinate points are connected in sequence to obtain the second functional relationship linear curve corresponding to the multi-machine drive mode when the transmission connected by the first motor drive is in first gear and the transmission connected by the second motor drive is in first gear, which is marked as the third multi-machine function relationship linear curve.

8. The dual-motor electric driving method according to claim 6, characterized in that: The step of obtaining a driving mode corresponding to the target vehicle speed and the target torque and marking the driving mode to obtain the target driving mode includes: If it is determined that the coordinate points of the target vehicle speed and the target torque in the first rectangular coordinate system are only within the area enclosed by the first single-machine function relationship linear curve and the second single-machine function relationship linear curve, the driving mode corresponding to the first single-machine function relationship linear curve is used as the target driving mode.

9. The dual-motor electric driving method according to claim 4, characterized in that: The preset curve database includes a first single-machine function relationship linear curve, a second single-machine function relationship linear curve, a third multi-machine function relationship linear curve and a second multi-machine function relationship linear curve. The step of obtaining a drive mode corresponding to the target vehicle speed and the target torque and marking the drive mode to obtain the target drive mode includes: When it is determined that the target vehicle speed and the target torque are within the region enclosed by the first single-machine function relationship linear curve and the second single-machine function relationship linear curve, and when it is determined that the target vehicle speed and the target torque are within the region enclosed by the third multi-machine function relationship linear curve and the second multi-machine function relationship linear curve, a vehicle operation parameter is acquired, and the vehicle operation parameter at least includes a real-time vehicle speed and a rotation speed of the first motor and the second motor; Calculate a first energy consumption corresponding to the first single-machine function relationship linear curve and a second energy consumption corresponding to the third multi-machine function relationship linear curve according to the vehicle operating parameters, the target vehicle speed and the target torque; A driving mode corresponding to a minimum value between the first energy consumption and the second energy consumption is used as the target driving mode.

10. The dual-motor electric driving method according to claim 5, characterized in that: The step of constructing a first rectangular coordinate system with the first historical vehicle speed as the X-axis and the first historical torque as the Y-axis, constructing a second rectangular coordinate system with the second historical vehicle speed as the X-axis and the second historical torque as the Y-axis, and obtaining and marking a drive mode corresponding to the target vehicle speed and the target torque to obtain a target drive mode includes: When it is determined that the coordinate points of the target vehicle speed and the target torque in the first rectangular coordinate system are within the region enclosed by the second single-machine function relationship linear curve and the X-axis of the first rectangular coordinate system, and when it is determined that the coordinate points of the target vehicle speed and the target torque in the second rectangular coordinate system are within the region enclosed by the second multi-machine function relationship linear curve and the X-axis of the second rectangular coordinate system, vehicle operation parameters are acquired, the vehicle operation parameters at least including the real-time vehicle speed and the rotation speeds of the first motor and the second motor; According to the vehicle operating parameters, the target vehicle speed and the target torque, respectively calculate the third energy consumption corresponding to the second single-machine function relationship linear curve, the fourth energy consumption corresponding to the second multi-machine function relationship linear curve and the fifth energy consumption corresponding to the first multi-machine function relationship linear curve; A driving mode corresponding to a minimum value among the third energy consumption, the fourth energy consumption and the fifth energy consumption is used as the target driving mode.

11. The dual-motor electric driving method according to claim 9, characterized in that: After the step of taking the driving mode corresponding to the minimum value of the first energy consumption and the second energy consumption as the target driving mode, the method further comprises: When it is determined that the second energy consumption is less than the first energy consumption, obtaining the maximum torque of the first motor; dividing the maximum torque into a plurality of first partial torques at set torque intervals; controlling the rotation speed of the first motor to remain unchanged, and calculating the first power consumption of the first motor corresponding to each of the first partial torques; Determine a torque corresponding to a minimum value among the plurality of first power consumptions as a current torque of the first motor; determining a current torque of the second motor according to the target torque and a current torque of the first motor; A first torque request is sent to a controller of the first electric machine to cause the first electric machine to respond and operate at the first electric machine's current torque, and a second torque request is sent to a controller of the second electric machine to cause the second electric machine to respond and operate at the second electric machine's current torque.

12. The dual-motor electric driving method according to claim 11, characterized in that: The step of determining the current torque of the second motor according to the target torque and the current torque of the first motor comprises: calculating a torque difference between the target torque and a current torque of the first motor; controlling the rotation speed of the second motor to remain unchanged, and calculating the second power consumption of the second motor corresponding to all first partial torques that are smaller than the torque difference among the plurality of first partial torques; Determine the torque corresponding to the minimum value of the multiple second power consumptions as the current torque of the second motor.

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