A distributed electric drive system and a control method thereof

Abstract

The present application provides a kind of distributed electric drive system and its control method, wherein the system includes: first drive unit, for driving first wheel rotation;Second drive unit, for driving second wheel rotation;Clutch, the clutch is arranged between the power output shaft of the first drive unit and the second drive unit;And electronic controller, for controlling the rotational speed and torque of the two ends of the coupling shaft of the clutch, and control the clutch combination or separation.By setting clutch, the torque redistribution of two drive units can be easily realized, when a certain wheel loses adhesion and gets into idle running, by controlling clutch combination, the wheel end torque of single wheel is multiplied by the resultant force, and the wheel with adhesion can still maintain sufficient power output to help vehicle out of trouble, further enhance the passability of off-road;Through these control methods, the combination or separation of clutch can be more smooth, and the response speed of clutch can be accelerated.

Description

Technical Field

[0001] This invention relates to the field of new energy vehicle technology, and in particular to a distributed electric drive system and its control method. Background Technology

[0002] With the increasing prominence of energy and environmental problems caused by traditional automobiles, the research and development of energy-saving and new energy vehicles has received attention from various countries and has become a hot topic in the industry. Electric vehicles are the most important form of new energy vehicles, with advantages such as comfort, cleanliness, low noise, low pollution, simple and reliable operation, and low operating costs. Integration, lightweighting, modularization, high power density, and high reliability have become the research directions for electric vehicle drive system technology.

[0003] Currently, electric vehicle drive systems are primarily centralized, with electric motors replacing the traditional engine. Power flows from the motor to the wheels, passing through reducers, differentials, drive shafts, and other transmission mechanisms, resulting in relatively low transmission efficiency. Benefiting from the flexibility of electrical component placement, distributed drive technology has become a hot research topic in electric drive systems. It uses two or more motors to independently drive their respective wheels, eliminating the differential mechanism, shortening the drivetrain length, and reducing the power and torque requirements of individual motors. This facilitates system integration, lightweighting, and modular design.

[0004] The main structural feature of a distributed drive system is that the motor is directly installed inside or near the wheel. Based on the relative positions of the wheel, motor, and reducer / gearbox, there are three arrangement schemes: central dual motor type, wheel-side motor type, and wheel hub motor type.

[0005] In a distributed drive system, the left and right wheels are controlled independently, eliminating the need for a differential and differential lock. The differential effect between the left and right wheels can be achieved in real time through a central computing platform and motor controller, which senses, calculates, and controls the wheel speeds. However, the electronic differential lock can only brake the wheel on the slipping side and cannot achieve torque redistribution from the distributed motor. Summary of the Invention

[0006] In view of the above-mentioned defects of the prior art, the present invention provides a distributed electric drive system and its control method to solve the technical problems of inability to achieve torque redistribution, low transmission efficiency, low integration degree and non-compact structure.

[0007] To achieve the above and other related objectives, the present invention provides a distributed electric drive system, comprising: a first drive unit for driving a first wheel to rotate; a second drive unit for driving a second wheel to rotate; a clutch disposed between the power output shafts of the first drive unit and the second drive unit; and an electronic controller for controlling the rotational speed and torque at both ends of the coupling shaft of the clutch, and controlling the engagement or disengagement of the clutch.

[0008] In one embodiment of the present invention, the clutch is a rigid clutch.

[0009] In one embodiment of the present invention, the first drive unit and the second drive unit are symmetrically arranged on the front axle or the rear axle of the vehicle; the first drive unit includes a first motor and a first reducer, the first motor driving the first wheel to rotate through the first reducer; the second drive unit includes a second motor and a second reducer, the second motor driving the second wheel to rotate through the second reducer; the clutch connects the first driving gear of the first reducer and the second driving gear of the second reducer, or connects the first driven gear of the first reducer and the second driven gear of the second reducer; the electronic controller controls the speed and torque of the first motor and the second motor.

[0010] To achieve the above and other related objectives, the present invention provides a control method for a distributed electric drive system applied to the electronic controller of the distributed electric drive system described in any of the above claims. The control method includes the following steps: monitoring the vehicle's coefficient of adhesion or a user-issued command; adjusting the rotational speeds at both ends of the coupling shaft of the clutch when the coefficient of adhesion is less than a set threshold or when a coupling command is received; controlling the clutch to engage when the speed difference at both ends of the coupling shaft is less than or equal to a preset speed difference, while simultaneously adjusting the torque at both ends of the coupling shaft to maintain the speed difference at both ends of the coupling shaft; and adjusting the torque at both ends of the coupling shaft to converge towards the torque gradient required by the driver when a clutch engagement signal is received.

[0011] In one embodiment of the present invention, the step of adjusting the rotational speed at both ends of the coupling shaft of the clutch includes: issuing a first control command to a first motor and a second motor to adjust the first motor and the second motor to a speed control mode; when receiving a first feedback signal issued by the first motor and the second motor after responding to the first control command and performing a mode switching action, issuing a second control command to the first motor and the second motor to adjust the rotational speed of the first motor and the second motor.

[0012] In one embodiment of the present invention, the step of controlling the clutch to engage when the speed difference between the two ends of the coupling shaft is less than or equal to a preset speed difference, and simultaneously adjusting the torque at both ends of the coupling shaft to maintain the speed difference between the two ends of the coupling shaft, includes: acquiring the speeds of the first motor and the second motor, and calculating the speed difference; when the speed difference is less than or equal to the preset speed difference, issuing a third control command to the first motor and the second motor to adjust the first motor and the second motor to a torque control mode; when receiving a second feedback signal issued by the first motor and the second motor after responding to the third control command and performing a mode switching action, issuing a fifth control command to control the clutch to engage; during the engagement process, calculating the internal torque loss based on the speeds of the first motor and the second motor, and issuing a fourth control command to the first motor and the second motor to adjust the torque of the first motor and the second motor to only offset the internal torque loss.

[0013] In one embodiment of the present invention, the step of calculating the internal torque loss based on the rotational speeds of the first motor and the second motor includes: obtaining the rotational speeds of the first motor and the second motor; and calculating the torque maintained at the rotational speed based on the output power of the first motor and the second motor, which is the internal torque loss.

[0014] To achieve the above and other related objectives, the present invention provides a control method for a distributed electric drive system applied to the electronic controller of the distributed electric drive system described in any of the above claims. The control method includes the following steps: monitoring the vehicle's coefficient of adhesion or a user-issued command; adjusting the torque at both ends of the coupling shaft of the clutch when the coefficient of adhesion is greater than or equal to a set threshold or when a decoupling command is received; controlling the clutch to disengage when the torque difference at both ends of the coupling shaft is less than or equal to a preset torque difference, while simultaneously adjusting the torque at both ends of the coupling shaft to maintain the speed difference at both ends of the coupling shaft; and adjusting the torque at both ends of the coupling shaft to converge towards the torque gradient required by the driver when a clutch disengagement signal is received.

[0015] In one embodiment of the present invention, the step of adjusting the torque at both ends of the coupling shaft of the clutch includes: issuing a third control command to the first motor and the second motor to adjust the first motor and the second motor to a torque control mode; when receiving a second feedback signal issued by the first motor and the second motor after responding to the third control command by performing a mode switching action, issuing a fourth control command to the first motor and the second motor to adjust the torque of the first motor and the second motor.

[0016] In one embodiment of the present invention, the step of controlling the clutch to disengage when the torque difference between the two ends of the coupling shaft is less than or equal to a preset torque difference, and simultaneously adjusting the torque at both ends of the coupling shaft to maintain the speed difference between the two ends of the coupling shaft includes: acquiring the torques of the first motor and the second motor, and calculating the torque difference; when the torque difference is less than or equal to the preset torque difference, issuing a sixth control command to control the clutch to disengage; during the disengagement process, calculating the internal torque loss based on the speeds of the first motor and the second motor, and issuing a fourth control command to the first motor and the second motor to adjust the torques of the first motor and the second motor to only offset the internal torque loss.

[0017] The beneficial effects of this invention are as follows: This invention proposes a distributed electric drive system and its control method. In this system, by setting a clutch between the first drive unit and the second drive unit, the torque redistribution between the two drive units can be easily realized. When a wheel loses traction and becomes idling, by controlling the clutch to engage, the combined force doubles the wheel-end torque of the single wheel, while the wheel with traction can still maintain sufficient power output, helping the vehicle get out of trouble and further enhancing off-road capability. Through these control methods, the engagement or disengagement of the clutch can be made smoother, and the clutch response speed can be accelerated. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the system structure provided in an embodiment of the present invention;

[0020] Figure 2 This is a first chassis configuration diagram provided in an embodiment of the present invention;

[0021] Figure 3 This is a second chassis configuration diagram provided in an embodiment of the present invention;

[0022] Figure 4 This is a third chassis configuration diagram provided in one embodiment of the present invention;

[0023] Figure 5 This is a fourth chassis configuration diagram provided in one embodiment of the present invention;

[0024] Figure 6 This is a fifth chassis configuration diagram provided in one embodiment of the present invention;

[0025] Figure 7 This is a coupling flowchart provided in one embodiment of the present invention;

[0026] Figure 8 yes Figure 7 The sub-flowchart of the second step;

[0027] Figure 9 yes Figure 7 The sub-flowchart of the third step;

[0028] Figure 10 yes Figure 9 The sub-flowchart for calculating internal torque loss;

[0029] Figure 11 This is a decoupling flowchart provided in an embodiment of the present invention;

[0030] Figure 12 yes Figure 11 The sub-flowchart of the second step;

[0031] Figure 13 yes Figure 11 The flowchart for the third step.

[0032] Explanation of reference numerals in the attached drawings: 100, first drive unit; 110, first motor; 120, first reducer; 121, first drive gear; 122, first driven gear; 200, second drive unit; 210, first motor; 220, second reducer; 221, second drive gear; 222, second driven gear; 300, clutch; A, first wheel; B, second wheel. Detailed Implementation

[0033] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. It should be noted that, unless otherwise specified, the following embodiments and features can be combined with each other. In addition to the specific methods, equipment, and materials used in the embodiments, based on the knowledge of the prior art and the description of the present invention by those skilled in the art, any prior art methods, equipment, and materials similar to or equivalent to those described in the embodiments of the present invention can be used to implement the present invention.

[0034] It should be understood that the terminology used in the embodiments of this invention is for describing specific implementations and not for limiting the scope of protection of this invention. Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art.

[0035] The structures, proportions, and sizes illustrated in the accompanying drawings are solely for illustrative purposes and to aid those skilled in the art in understanding and reading the invention. They are not intended to limit the implementation of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and objectives of the invention, should still fall within the scope of the technical content disclosed herein. Furthermore, the drawings only show components relevant to the invention and are not drawn according to the actual number, shape, and size of components in practice. In actual implementation, the type, quantity, and proportion of each component can be arbitrarily changed, and the component layout may be more complex.

[0036] In the following description, numerous details are explored to provide a more thorough explanation of embodiments of the invention. However, it will be apparent to those skilled in the art that embodiments of the invention may be practiced without these specific details. In some embodiments, well-known structures and devices are shown in block diagram form rather than in detail to avoid obscuring embodiments of the invention.

[0037] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functions, and operations that may be implemented in the methods and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0038] Please see Figure 1 , Figure 1A distributed electric drive system provided in one embodiment of the present invention includes: a first drive unit 100 for driving a first wheel A to rotate; a second drive unit 200 for driving a second wheel B to rotate; a clutch 300 disposed between the power output shafts of the first drive unit 100 and the second drive unit 200; and an electronic controller for controlling the rotational speed and torque at both ends of the coupling shaft of the clutch 300, and controlling the engagement or disengagement of the clutch 300. The electronic controller can be an existing control system of the vehicle itself, such as an electronic stability system or other control system, or a separate electronic controller can be provided. By setting the clutch 300 between the first drive unit 100 and the second drive unit 200, the torque redistribution of the two drive units can be easily realized. When a wheel loses traction and becomes idle, by controlling the engagement of the clutch 300, the combined force multiplies the wheel-end torque of the single wheel, while the wheel with traction can still maintain sufficient power output, helping the vehicle get out of trouble and further enhancing off-road passability; at the same time, it can also improve transmission efficiency and space utilization.

[0039] Specifically, when a vehicle encounters potholes, mud, desert, or other road conditions, whether it's a cross-axle situation or an extremely muddy and slippery surface, one or more wheels may lose traction and spin. The driver can control the clutch 300 to engage via a knob or lever, or the vehicle can automatically engage the clutch 300 based on the coefficient of friction to achieve a combined drive mode. In this mode, the clutch 300 concentrates the power of the first drive unit 100 and the second drive unit 200 on the same wheel, mechanically locking the left and right half-axles. This combined force doubles the torque at the wheel end of each wheel, ensuring that the wheel with traction maintains sufficient power output to help the vehicle overcome difficulties, further optimizing torque distribution and improving passability. On highways, the clutch 300 disengages to achieve a distributed drive mode, allowing for smoother turns and protecting the vehicle's transmission system.

[0040] There are many types of clutches 300, such as multi-plate wet friction clutches, claw clutches, etc. In order to improve the power transmission effect, in a specific embodiment of the present invention, the clutch 300 is a rigid clutch. Using a rigid clutch can better realize the power transmission, apply the force of two drive units to a single wheel, and reduce friction loss.

[0041] There are many options for rigid clutches, such as claw clutches. A claw clutch typically includes: two end faces connected by a guide key or spline; a magnetic drive unit to drive one end face axially toward the other; a return spring to reset the movable end face; and a position sensor to detect the distance between the two end faces. To engage the claw clutch, the magnetic drive unit is powered on, providing magnetic force to attract one end face toward the other, thus engaging the clutch. To disengage the clutch, the magnetic drive unit is de-energized, and the return spring causes one end face to move away from the other, disengaging the clutch. The position sensor can output the distance between the two end faces and also output a switching signal when the clutch is fully engaged or disengaged.

[0042] Depending on the different positions of the first drive unit 100 and the second drive unit 200 on the vehicle, there can be various specific embodiments. The following describes some common embodiments in detail.

[0043] Please see Figure 1 and 2 In a specific embodiment of the present invention, a first drive unit 100 and a second drive unit 200 are symmetrically arranged on the front axle of the vehicle. The first drive unit 100 includes a first motor 110 and a first reducer 120. The first motor 110 drives the first wheel A to rotate through the first reducer 120. Other components, such as a universal joint, may also be included between the first reducer 120 and the first wheel A. The second drive unit 200 includes a second motor 210 and a second reducer 220. The second motor 210 drives the second wheel B to rotate through the second reducer 220. A clutch 300 connects the first driving gear 121 of the first reducer 120 and the second driving gear 221 of the second reducer 220, or connects the first driven gear 122 of the first reducer 120 and the second driven gear 222 of the second reducer 220. An electronic controller controls the speed and torque of the first motor 110 and the second motor 210. The first chassis configuration is as follows: Figure 2 As shown, both the first drive unit 100 and the second drive unit 200 are mounted on the front axle of the vehicle, and the first wheel A and the second wheel B are the front wheels of the vehicle. This distributed electric drive system has a compact structure, high transmission efficiency, and a very high degree of integration.

[0044] Please see Figure 3In a specific embodiment of the present invention, the first drive unit 100 and the second drive unit 200 are symmetrically arranged on the rear axle of the vehicle; the specific structures of the first drive unit 100, the second drive unit 200, the clutch 300, and the electronic controller are the same as the first chassis configuration, and the first wheel A and the second wheel B correspond to the rear wheels of the vehicle. The second chassis configuration is as follows: Figure 3 As shown, the difference between the second chassis configuration and the first chassis configuration is that the first chassis configuration adopts a front-mounted dual electric drive scheme, while the second chassis configuration adopts a rear-mounted dual electric drive scheme.

[0045] Please see Figure 4 In a specific embodiment of the present invention, the first drive unit 100 and the second drive unit 200 are symmetrically arranged on the front axle of the vehicle. The specific structures of the first drive unit 100, the second drive unit 200, the clutch 300, and the electronic controller are the same as those of the first chassis configuration. A third drive unit is also arranged on the rear axle of the vehicle. The third drive unit simultaneously drives the two rear wheels of the vehicle to rotate. A clutch 300 is also arranged between the third drive unit and the power output shaft of the first drive unit 100 / second drive unit 200. The third chassis configuration is as follows: Figure 4 As shown, in this embodiment, the power of the three drive units can be further concentrated on some of the wheels, further optimizing the vehicle's torque distribution capability.

[0046] Please see Figure 5 In a specific embodiment of the present invention, the first drive unit 100 and the second drive unit 200 are symmetrically arranged on the rear axle of the vehicle. The specific structures of the first drive unit 100, the second drive unit 200, the third drive unit, the clutch 300, and the electronic controller are the same as those of the third chassis configuration. The fourth chassis configuration is as follows: Figure 5 As shown, the difference between the third chassis configuration and the fourth chassis configuration is that the third chassis configuration adopts a front-two-rear-one electric drive scheme, while the fourth chassis configuration adopts a front-one-rear-two electric drive scheme.

[0047] Please see Figure 6 In a specific embodiment of the present invention, the first drive unit 100 and the second drive unit 200 are symmetrically arranged on the front axle and rear axle of the vehicle, that is, there are two sets of the first drive unit 100, the second drive unit 200, and the clutch 300, one set on the front axle and the other set on the rear axle. A third clutch 300 is arranged between the first drive unit 100 / second drive unit 200 on the front axle and the first drive unit 100 / second drive unit 200 on the rear axle. The fifth chassis configuration is as follows: Figure 6As shown, in this scheme, the torque distribution between the two front wheels of the vehicle can be achieved by controlling the clutch 300 on the front axle, and the torque distribution between the two rear wheels of the vehicle can be achieved by controlling the clutch 300 on the rear axle. Furthermore, after the clutches 300 on the front axle and the rear axle are engaged, controlling the third clutch 300 to engage can achieve torque redistribution among the four motors.

[0048] In addition to the specific embodiments listed above, other embodiments may also be included, such as the third, fourth, and fifth chassis configurations, where the clutch 300 between the front and rear axles is removed.

[0049] For the aforementioned distributed electric drive system, it is necessary to control the engagement or disengagement of the clutch 300 to achieve coupling or decoupling of the first drive unit 100 and the second drive unit 200. To make the coupling and decoupling process smoother and accelerate the clutch response speed, this invention also provides a control method for a distributed electric drive system, the specific embodiments of which are described below.

[0050] Before describing the specific embodiments below, the signals sent and received by the electronic controller will be explained. A first control command is used to adjust the motor to a speed control mode; a second control command is used to adjust the motor speed; a third control command is used to adjust the motor to a torque control mode; a fourth control command is used to adjust the motor torque; a fifth control command is used to control the engagement of the clutch 300; a sixth control command is used to control the disengagement of the clutch 300; a first feedback signal is the signal sent when the motor switches to speed control mode; a second feedback signal is the signal sent when the motor switches to torque control mode.

[0051] Please see Figure 7 , Figure 7 This invention provides a distributed electric drive method, applied to the electronic controller of the aforementioned distributed electric drive system. The control method includes the following steps: monitoring the vehicle's coefficient of friction or user-issued commands. The coefficient of friction is the ratio of the adhesion force to the wheel's normal (perpendicular to the road surface) pressure. Roughly calculated, it can be considered as the static friction coefficient between the tire and the road surface. It is determined by the road surface and the tire; the larger this coefficient, the greater the available adhesion force, and the less likely the vehicle is to slip. Therefore, the coefficient of friction can be used to determine whether the vehicle is slipping. User-issued commands can be, for example, commands issued by the user rotating a knob, turning a joystick, or pressing a switch, etc.

[0052] When the vehicle's coefficient of friction is less than a set threshold or a coupling command is received, the rotational speeds at both ends of the coupling shaft of the clutch 300 are adjusted. When the vehicle's coefficient of friction is less than the set threshold, it indicates that the vehicle is slipping, and the coupling process can be executed automatically. When a coupling command is received, it is equivalent to the driver actively choosing to execute the coupling process based on the current driving situation. In a specific embodiment, there may be only one determination condition or two determination conditions. When both determination conditions exist, it should be noted that their relationship is "OR," that is, the coupling process will be executed if either condition is true.

[0053] When the speed difference between the two ends of the coupling shaft is less than or equal to the preset speed difference, the clutch 300 is engaged, and the torque at both ends of the coupling shaft is adjusted to maintain the speed difference. This preset speed difference is pre-set; in reality, no matter how it is adjusted, the speed difference will never be perfectly equal. Therefore, the preset speed difference is used to determine if the speed difference is small enough. When a clutch 300 closing signal is received, the torque at both ends of the coupling shaft is adjusted to converge towards the torque gradient required by the driver. Gradient convergence can be understood as a smooth transition, not a sudden adjustment. In this embodiment, by controlling the speed and torque at both ends of the coupling shaft of the clutch 300, the two ends of the coupling shaft maintain the same speed and torque before engagement; during engagement, the speed difference is maintained; after engagement, the torque is adjusted to respond to the driver's needs. By controlling the entire coupling process, the clutch 300 engages very smoothly, accelerating the clutch response speed and improving the user's driving comfort. In actual implementation, the entire process is very short, taking only milliseconds.

[0054] Please see Figure 8 In a specific embodiment of the present invention, the step of adjusting the rotational speed at both ends of the coupling shaft of the clutch 300 includes: issuing a first control command to the first motor 110 and the second motor 210 to adjust the first motor 110 and the second motor 210 to a speed control mode; when receiving a first feedback signal issued by the first motor 110 and the second motor 210 after responding to the first control command and performing a mode switching action, issuing a second control command to the first motor 110 and the second motor 210 to adjust the rotational speed of the first motor 110 and the second motor 210. The rotational speed at both ends of the coupling shaft of the clutch 300 is controlled by the first drive unit 100 and the second drive unit 200, specifically by the first motor 110 and the second motor 210. Therefore, in this embodiment, the first motor 110 and the second motor 210 are controlled to achieve speed control at both ends of the coupling shaft of the clutch 300.

[0055] Please see Figure 9In a specific embodiment of the present invention, when the speed difference between the two ends of the coupling shaft is less than or equal to a preset speed difference, the step of controlling the clutch 300 to engage and simultaneously adjusting the torque at both ends of the coupling shaft to maintain the speed difference between the two ends of the coupling shaft includes: obtaining the speeds of the first motor 110 and the second motor 210, and calculating the speed difference. It should be noted that in this embodiment, the speed transmission ratio between the first motor 110 and one end of the coupling shaft is the same as the speed transmission ratio between the second motor 210 and the other end of the coupling shaft, that is, the speed difference between the first motor 110 and the second motor 210 is proportional to the speed difference between the two ends of the coupling shaft; when the speed difference between the first motor 110 and the second motor 210 is less than a preset speed difference, the step of controlling the clutch 300 to engage and simultaneously adjusting the torque at both ends of the coupling shaft to maintain the speed difference between the two ends of the coupling shaft includes: obtaining the speeds of the first motor 110 and the second motor 210, and calculating the speed difference. When the speed difference equals the preset value, a third control command is issued to the first motor 110 and the second motor 210 to adjust them to torque control mode. Upon receiving a second feedback signal from the first motor 110 and the second motor 210 after responding to the third control command and performing a mode switching action, a fifth control command is issued to control the clutch 300 to engage. During engagement, the internal torque loss is calculated based on the rotational speeds of the first motor 110 and the second motor 210, and a fourth control command is issued to the first motor 110 and the second motor 210 to adjust their torques to only offset the internal torque loss. In this embodiment, while the clutch 300 engages, the torques of the first motor 110 and the second motor 210 are continuously controlled to offset the internal torque loss and promptly compensate for the speed difference between the two ends of the clutch 300, thereby achieving a smoother engagement of the clutch 300.

[0056] Please see Figure 10 In a specific embodiment of the present invention, the step of calculating the internal torque loss based on the rotational speeds of the first motor 110 and the second motor 210 includes: obtaining the rotational speeds of the first motor 110 and the second motor 210; and calculating the torque maintained at those rotational speeds based on the output power of the first motor 110 and the second motor 210, which is the internal torque loss. There are many formulas for calculating torque; this embodiment provides one calculation scheme. It is understood that other parameters and formulas can also be used to calculate the internal torque loss.

[0057] Please see Figure 11 , Figure 11This invention provides a distributed electric drive method applied to the electronic controller of the aforementioned distributed electric drive system. The control method includes the following steps: monitoring the vehicle's adhesion coefficient or user-issued commands; adjusting the torque at both ends of the coupling shaft of the clutch 300 when the adhesion coefficient is greater than or equal to a set threshold or when a decoupling command is received; similarly, in a specific embodiment, there may be only one determination condition or two determination conditions. When both determination conditions exist, it should be noted that their relationship is "OR," meaning that the decoupling process will be executed when either condition is met. When the torque difference at both ends of the coupling shaft is less than or equal to a preset torque difference, the clutch 300 is disengaged, and the torque at both ends of the coupling shaft is adjusted to maintain the speed difference at both ends of the coupling shaft; when a clutch 300 open signal is received, the torque at both ends of the coupling shaft is adjusted to converge towards the torque gradient required by the driver. In this embodiment, since the clutch 300 is initially in a coupled state, the speeds at both ends of the coupling shaft remain consistent, so there is no need to focus on the speed initially. By controlling the torque at both ends of the coupling shaft of clutch 300, the two ends of the coupling shaft maintain the same torque before disengagement; during disengagement, the speed difference is maintained; and after disengagement, the torque is adjusted to respond to the driver's needs. By controlling the entire decoupling process, clutch 300 disengages very smoothly and responds very quickly, improving the user's driving comfort.

[0058] Please see Figure 12 In a specific embodiment of the present invention, the step of adjusting the torque at both ends of the coupling shaft of the clutch 300 includes: issuing a third control command to the first motor 110 and the second motor 210 to adjust the first motor 110 and the second motor 210 to a torque control mode; when receiving a second feedback signal issued by the first motor 110 and the second motor 210 after responding to the third control command and performing a mode switching action, issuing a fourth control command to the first motor 110 and the second motor 210 to adjust the torque of the first motor 110 and the second motor 210. The torque at both ends of the coupling shaft of the clutch 300 is driven by the first drive unit 100 and the second drive unit 200, specifically controlled by the first motor 110 and the second motor 210. Therefore, in this embodiment, the first motor 110 and the second motor 210 are controlled to achieve torque control at both ends of the coupling shaft of the clutch 300.

[0059] Please see Figure 13In a specific embodiment of the present invention, the steps of controlling the clutch 300 to disengage when the torque difference between the two ends of the coupling shaft is less than or equal to a preset torque difference, and simultaneously adjusting the torque at both ends of the coupling shaft to maintain the speed difference between the two ends of the coupling shaft, include: acquiring the torques of the first motor 110 and the second motor 210, and calculating the torque difference; when the torque difference is less than or equal to the preset torque difference, issuing a sixth control command to control the clutch 300 to disengage; during the disengagement process, calculating the internal torque loss based on the speeds of the first motor 110 and the second motor 210, and issuing a fourth control command to the first motor 110 and the second motor 210 to adjust the torques of the first motor 110 and the second motor 210 to only offset the internal torque loss. The control logic of the clutch 300 disengagement process is basically similar to that of the engagement process. By precisely controlling the torques of the first motor 110 and the second motor 210, the speed difference between the two ends of the coupling shaft is maintained, thereby achieving smooth disengagement of the clutch 300.

[0060] When applying the above control method to the specific chassis configuration embodiments described above, the above control method can be directly applied to both the first and second chassis configurations.

[0061] For the second and third chassis configurations, when coupling is required, the above control method is applied to engage the clutch 300 located on the front or rear axle, and then the clutch 300 located between the front and rear axles is manually engaged. When decoupling is required, the clutch 300 located between the front and rear axles is first manually disengaged, and then the above control method is applied to disengage the clutch 300 located on the front or rear axle. The order of these steps is important.

[0062] For the fourth and fifth chassis configurations, the same approach applies: when coupling is required, the above control method is used to engage the clutches 300 located on the front and rear axles, and then the clutches 300 located between the front and rear axles are manually engaged; when decoupling is required, the clutches 300 located between the front and rear axles are first manually disengaged, and then the above control method is used to disengage the clutches 300 located between the front and rear axles.

[0063] In summary, this invention has many advantages. First, it employs a rigid clutch, eliminating slippage, resulting in a simple structure, large torque transmission capacity, high transmission efficiency, and small footprint. This allows for torque redistribution within the electric drive system, leading to superior energy efficiency and dynamic control performance. Second, the clutch 300 concentrates the power of two coaxial motors onto a single wheel, enhancing off-road performance. When one or more wheels lose traction and spin freely, the clutch 300 mechanically locks the left and right half-shafts, multiplying the torque at the wheel end through combined force. Wheels with traction maintain sufficient power output, helping the vehicle overcome difficulties and further enhancing off-road capability. Third, the electric drive system can be integrated into the vehicle body according to user needs, improving overall system compactness, saving longitudinal space, and resulting in a simple structure and low manufacturing cost. Fourth, the electric drive system proposed in this invention can be configured into different chassis configurations, with matching motors and reducers to adapt to different vehicle models, demonstrating strong versatility.

[0064] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A distributed electric drive system, characterized in that, include: The first drive unit is used to drive the first wheel to rotate; The second drive unit is used to drive the second wheel to rotate; A clutch, wherein the clutch is disposed between the power output shafts of the first drive unit and the second drive unit; and An electronic controller is used to control the speed and torque at both ends of the coupling shaft of the clutch, and to control the engagement or disengagement of the clutch; The electronic controller is further configured to: when the speed difference between the two ends of the coupling shaft is less than or equal to a preset speed difference, acquire the speeds of the first motor of the first drive unit and the second motor of the second drive unit, and calculate the speed difference; when the speed difference is less than or equal to the preset speed difference, issue a third control command to the first motor and the second motor to adjust the first motor and the second motor to torque control mode; when receiving a second feedback signal issued by the first motor and the second motor after responding to the third control command and performing a mode switching action, issue a fifth control command to control the clutch to engage; during engagement, calculate the internal torque loss based on the speeds of the first motor and the second motor, and issue a fourth control command to the first motor and the second motor to adjust the torque of the first motor and the second motor to only offset the internal torque loss; The electronic controller is also configured to: when the torque difference between the two ends of the coupling shaft is less than or equal to a preset torque difference, acquire the torque of the first motor and the second motor, and calculate the torque difference; when the torque difference is less than or equal to the preset torque difference, issue a sixth control command to control the clutch to disengage; during the disengagement process, calculate the internal torque loss based on the rotational speeds of the first motor and the second motor, and issue a fourth control command to the first motor and the second motor to adjust the torque of the first motor and the second motor to only offset the internal torque loss.

2. The distributed electric drive system according to claim 1, characterized in that, The clutch is a rigid clutch.

3. The distributed electric drive system according to claim 1, characterized in that, The first drive unit and the second drive unit are symmetrically arranged on the front axle or the rear axle of the vehicle. The first drive unit includes a first motor and a first reducer, wherein the first motor drives the first wheel to rotate through the first reducer; The second drive unit includes a second motor and a second reducer, wherein the second motor drives the second wheel to rotate through the second reducer; The clutch connects the first driving gear of the first reducer and the second driving gear of the second reducer, or connects the first driven gear of the first reducer and the second driven gear of the second reducer; The electronic controller controls the speed and torque of the first motor and the second motor.

4. A control method for a distributed electric drive system, characterized in that, An electronic controller applied to a distributed electric drive system as described in any one of claims 1 to 3, the control method comprising the following steps: Monitor the vehicle's adhesion coefficient or user-issued commands; When the adhesion coefficient is less than a set threshold or when a coupling command is received, the rotational speed at both ends of the clutch coupling shaft is adjusted. When the speed difference between the two ends of the coupling shaft is less than or equal to the preset speed difference, the speeds of the first motor and the second motor are obtained, and the speed difference is calculated. When the speed difference is less than or equal to the preset speed difference, a third control command is issued to the first motor and the second motor to adjust the first motor and the second motor to torque control mode; When a second feedback signal is received after the first motor and the second motor have performed a mode switching action in response to the third control command, a fifth control command is issued to control the clutch to engage. During engagement, the internal torque loss is calculated based on the rotational speeds of the first motor and the second motor, and a fourth control command is issued to the first motor and the second motor to adjust the torques of the first motor and the second motor to only offset the internal torque loss. When the clutch engagement signal is received, the torque at both ends of the coupling shaft is adjusted to converge towards the torque gradient required by the driver.

5. The control method for a distributed electric drive system according to claim 4, characterized in that, The steps for adjusting the rotational speed at both ends of the clutch coupling shaft include: A first control command is issued to the first motor and the second motor to adjust the first motor and the second motor to a speed control mode; When a first feedback signal is received from the first motor and the second motor after they have performed a mode switching action in response to the first control command, a second control command is sent to the first motor and the second motor to adjust their speeds.

6. The control method for a distributed electric drive system according to claim 4, characterized in that, The step of calculating the internal torque loss based on the rotational speeds of the first motor and the second motor includes: Obtain the rotational speeds of the first motor and the second motor; The torque used to maintain this speed is calculated based on the output power of the first motor and the second motor, which is the internal torque loss.

7. A control method for a distributed electric drive system, characterized in that, An electronic controller applied to a distributed electric drive system as described in any one of claims 1 to 3, the control method comprising the following steps: Monitor the vehicle's adhesion coefficient or user-issued commands; When the adhesion coefficient is greater than or equal to a set threshold or when a decoupling command is received, the torque at both ends of the clutch coupling shaft is adjusted. When the torque difference between the two ends of the coupling shaft is less than or equal to the preset torque difference, the torques of the first motor and the second motor are obtained and the torque difference is calculated; when the torque difference is less than or equal to the preset torque difference, a sixth control command is issued to control the clutch to disengage. During the disengagement process, the internal torque loss is calculated based on the rotational speeds of the first motor and the second motor, and a fourth control command is issued to the first motor and the second motor to adjust the torques of the first motor and the second motor to only offset the internal torque loss. When the clutch is opened signal is received, the torque at both ends of the coupling shaft is adjusted to converge towards the torque gradient required by the driver.

8. The control method for a distributed electric drive system according to claim 7, characterized in that, The steps for adjusting the torque at both ends of the clutch coupling shaft include: A third control command is issued to the first motor and the second motor to adjust the first motor and the second motor to torque control mode; When a second feedback signal is received from the first motor and the second motor after they have performed a mode switching action in response to the third control command, a fourth control command is issued to the first motor and the second motor to adjust the torque of the first motor and the second motor.

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