METHOD FOR REDUCING THE TORQUE OF AN ELECTRIC MACHINE IN CASE OF LACK OF VEHICLE TRACTION ON THE GROUND

Abstract

A method for reducing the torque of an electric machine in the event of a loss of wheel traction in an electric or hybrid motor vehicle comprising an electrically driven axle, the vehicle including a dynamic stability control (ESP) system with a traction control function, an electric machine (ME1) and a control unit (UCE1) responsible for controlling the torque, the method comprising: 1- acquiring the wheel rotational speed of each wheel, 2- generating a lower and upper speed limit, 3- transmitting the lower and upper limits from the dynamic stability control system to the control unit, 4- reducing the motor torque by the control unit if the current rotational speed exceeds the upper limit or falls below the lower limit. Figure 2

Description

Title of the invention: METHOD FOR REDUCING THE TORQUE OF AN ELECTRIC MACHINE IN CASE OF LACK OF TRACTION OF A VEHICLE ON THE GROUND

[0001] The present invention relates generally to the field of traction control systems in motor vehicles, particularly in electric or hybrid vehicles. Particular interest here is a vehicle with at least one axle, front or rear, equipped with an electric drivetrain, namely with an electric motor and a differential transmission driving the two wheels of the axle in question.

[0002] In a motor vehicle, the drive wheels are capable of transmitting torque to the ground, this torque being defined with respect to the axis of the wheel in question.

[0003] The transmission of torque to the ground depends on the coefficient of friction between the tire and the ground at the point of contact between the tire and the ground, which can also generally be called 'adhesion'.

[0004] It may happen that the coefficient of friction does not allow the applied torque to be transmitted between the tire and the ground, in which case wheel slippage occurs.

[0005] Such slippage occurs, for example, in the case of significant braking force. Such slippage can also occur in the case of a drive torque to be transmitted to the ground.

[0006] The driving torque can be positive, meaning that the torque tends to increase the speed of the vehicle, or the torque can be negative, which corresponds to the case where the torque tends to decrease the speed of the vehicle (braking, engine braking including via a resistive electric machine torque with the electric machine in generator mode).

[0007] In this document, we are particularly interested in the anti-slip function, this function consisting of reducing the torque applied to the wheels by a powertrain or electric motor in the event that the adhesion between the tire and the ground proves insufficient to pass the torque applied between the tire and the ground.

[0008] More generally, the present invention relates to traction control (called in the trade ASR) and engine braking control (called in the trade MSR).

[0009] In an electric traction system, in zero-emission mode, the moment of inertia of the rotating parts (machine rotor and transmission element including differential and, where applicable, reduction gear) is smaller than the equivalent moment of inertia in an internal combustion engine, which involves a moving assembly including crankshaft, flywheel, connecting rods, and pistons. It should also be noted that the torque The availability of an electric motor is very significant at a low or zero rotation speed.

[0010] Therefore, during a strong acceleration from zero velocity, a slipping situation may occur.

[0011] Similarly, during the advance of the vehicle, a sudden change in grip of the contact area between the tire and the ground can lead to a slip, whether the torque is positive, i.e. in traction, or negative, i.e. in engine braking.

[0012] It is noted that this is valid not only for the usual case of forward movement (longitudinal movement towards the front of the vehicle), but also for the occasional case of reversing maneuver.

[0013] In the known art, the traction control system identifies the slippage problem and then generates a torque command to be requested from the engine control unit and transmits this torque command to the engine control unit. It should be noted that the engine control unit executes the lower of the two torque commands: the one resulting from the driver's intent and the one requested by the traction control system (generally lower in the case of traction slippage and higher in the case of slippage during engine braking / regenerative braking).

[0014] This correction process takes some time, in practice a few tens of milliseconds for example a time between 60 milliseconds and 100 milliseconds.

[0015] Meanwhile, and in view of the low moment of inertia in electric mode, as mentioned above, a significant wheel slippage could occur, i.e. a surge in wheel rotation speed in the case of traction for example or, conversely, a drastic decrease in the case of engine braking.

[0016] In this context, the inventors sought to propose a solution to reduce the reaction time of the anti-slip function and thus decrease the amplitude of wheel slippage, in order to improve vehicle stability.

[0017] To achieve this objective, the invention proposes a method for reducing the torque of an electric machine in the event of a lack of wheel traction in an electric or hybrid motor vehicle comprising at least one electrically driven axle by means of an electric motor unit, the vehicle comprising a dynamic stability control system including at least one traction control function acting on the electric motor unit, the electric motor unit comprising at least one electric machine and at least one motor control unit responsible for controlling the torque generated by the electric machine in real time, at least according to a setpoint representing the intent of a vehicle driver, the method comprising a basic loop including: 1- Acquisition, by the dynamic stability control system, of the wheel rotation speed of each of the wheels of the motorized axle, 2- generation by the dynamic stability control system of a lower speed limit and an upper speed limit for a reference shaft of the electromotor unit, 3- Transmission of the lower and upper rotational speed limits from the dynamic stability control system to the drive control unit, 4- Reduction of motor torque, by the motor control unit, if the current rotational speed of the reference shaft becomes greater than the upper rotational speed limit or if the current rotational speed of the reference shaft becomes less than the lower rotational speed limit.

[0018] Thanks to these provisions, the reaction time is reduced to a value between 15 ms and 30 ms, compared to 60 ms to 100 ms for the classic anti-slip loop.

[0019] This prevents a transient runaway of the slipping wheel or wheels. The proposed method functions as a preventive control that intervenes earlier than the so-called corrective control provided by the conventional traction control system. In other words, the proposed method initiates the traction control function locally in the electric machine's control unit, then transfers control to the traction control function managed by the dynamic stability control system.

[0020] Of course, if the torque reduction implemented by the control unit of the electric machine is not sufficient, the anti-slip regulation / feedback loop of the braking system intervenes in a second stage and regulates the slippage, by controlling the torque control (tractor or resistor) downwards, or even by selectively activating an individual braking action on a wheel that slips.

[0021] The "electric motor unit reference shaft" is a rotating element in the drive train. It should be noted here that the electric motor unit reference shaft can be either the output of the electric machine, i.e., the shaft carrying the rotor, or the input ring gear of the differential downstream of the gearbox. In practice, the system operates on the half-sum of the wheel speeds of the axle in question, as the drive control unit ignores the speed difference between the two wheels of the axle.

[0022] Moreover, as will be seen later, what is called 'a command representing the will of the vehicle driver' can come directly from the accelerator pedal or can come from a driving assistance system such as, for example, a speed regulator, a speed limiter, or even an adaptive distance following speed regulator.

[0023] Moreover, as will be seen later, the proposed invention can be applied to a single axle (front axle or rear axle of the vehicle) but can be applied equally to a two-axle configuration of the same vehicle.

[0024] In the remainder of this document, the computer of the vehicle's dynamic stability control system performing the traction control function will be referred to as the "ASR computer", the term "ASR computer" implying no functional limitation of this computer, the ABS, MSR and ESP functions being able to be performed by this computer.

[0025] According to an advantageous option, the basic loop is executed iteratively with a recurrence frequency of at least 100 Hz, preferably of at least 200 Hz.

[0026] It is noted that the lower and upper limits of rotational speed are always available and refreshed in the drive control unit even before slippage begins. Therefore, there is no delay related to communication between the dynamic stability control system and the drive control unit.

[0027] According to a particular example, the basic loop is executed iteratively with a frequency of 250 Hz, namely a loop period of 4 ms.

[0028] According to one embodiment, the dynamic stability control system (e.g. in particular the ASR computer) calculates a reference speed, namely an instantaneous longitudinal displacement speed of the vehicle, in order to generate the lower and upper limits of rotational speed, the reference speed being developed from the instantaneous rotational speeds of each of the wheels of the vehicle, in particular the last sampled values, i.e. the most recent.

[0029] The calculation of the reference speed may optionally also use information provided by at least one longitudinal acceleration sensor.

[0030] It is from the reference speed that the ASR computer, with regard to a generally tolerated slip, calculates the lower speed limit and the upper speed limit and transmits it to the engine control unit.

[0031] It is noted that the reference speed corresponds to the speed of the vehicle body.

[0032] According to one embodiment, the reference shaft of the electromotor unit is a shaft of output of the electric machine.

[0033] This is generally the shaft that carries the rotor of the electric machine. As a result, the speed information is directly usable by the motor control unit. Indeed, a position and speed sensor is provided on the rotor shaft in the basic design of the electric machine.

[0034] In practice, it is therefore the ASR computer that takes into account the average radius of the wheels, the gear ratio or reduction ratio between the engine output and the homokinetic transmission shafts to the wheels.

[0035] According to an alternative solution, the reference shaft could correspond to the differential's input ring gear, which matches the wheel rotation speed without slippage. In this case, the drive control unit must manage the reduction ratio relative to the machine's rotor shaft.

[0036] According to one embodiment, in circumstances where the torque generated by the electric machine is tractor, namely tending to increase the kinetic energy of the vehicle, it is the upper limit of rotational speed that will be stressed.

[0037] This scenario corresponds to wheel slippage during acceleration. It can occur in forward motion but also in reverse.

[0038] According to one embodiment, in circumstances where the torque generated by the electric machine is resistive, namely tending to decrease the kinetic energy of the vehicle, it is the lower limit of rotational speed that will be stressed.

[0039] This scenario corresponds to wheel slippage during engine braking deceleration. Here too, this can occur in forward motion as well as in reverse.

[0040] According to one embodiment, the dynamic stability control system communicates with the engine control unit via a CAN data bus with a data rate of at least 500 kilobits / s. In practice, a CAN network with a data rate of 1 megabit / s can be used, without excluding a higher-speed version, or the use of another type of high-speed network. It should be noted that a private multiplexed network can be used for data exchange between the ASR computer and the engine control unit.

[0041] Such a rapid flow rate makes it possible to transmit and update the low and high rotational speed limits at high frequency.

[0042] According to one embodiment, the method may further include a transmission of an anti-slip torque command issued by the dynamic stability control system to the drive control unit, and an execution of said anti-slip torque command by the drive control unit.

[0043] Once such an anti-slip torque command is issued by the ASR computer and received by the engine control unit, this torque command replaces the torque command initiated by the driver. This leads to a reduction in the torque value (tractor or load).

[0044] In other words, the anti-slip torque command from the dynamic stability control system transiently prevails over the torque command from the driver.

[0045] The present invention also relates to an electric or hybrid motor vehicle, comprising at least one electrically powered axle by means of an electric motor unit, a dynamic stability control system including at least one traction control function acting on the electric motor unit, the electric motor unit comprising at least one electric machine and at least one control unit the drive unit in charge of controlling the torque generated by the electric machine in real time, the drive control unit being configured to implement the process as defined previously.

[0046] This can typically relate to a hybrid vehicle which includes a powertrain with an internal combustion engine on the front axle and an electric drive unit with an electric drive chain on the rear axle.

[0047] The present invention also relates to an electric or hybrid motor vehicle, comprising a first axle electrically powered by a first electromotor group and a second axle electrically powered by a second electromotor group, a dynamic stability control system including at least one traction control function acting on the first and second electromotor groups, the first electromotor group comprising at least one first electric machine and at least one first drive control unit responsible for controlling the torque generated by the first electric machine in real time, the second electromotor group comprising at least one second electric machine and at least one second drive control unit responsible for controlling the torque generated by the second electric machine in real time,The first and second drive control units are configured to implement the process as defined above.

[0048] This typically relates to an electric vehicle which includes an electric drive unit with an electric drive chain on the front axle and another electric drive unit with another electric drive chain on the rear axle.

[0049] The invention will be further detailed by describing non-limiting embodiments, and based on the accompanying figures illustrating variants of the invention, in which: - [Fig.l] schematically illustrates in top view a synoptic diagram of the vehicle equipped with the traction control function; - [Fig. 2] shows a block diagram illustrating the operation of the process according to the present invention; - [Fig.3] represents a first example of a chronogram of a situation in speed increase; - [Fig. 4] represents a second example of a chronogram of a situation decreasing in speed.

[0050] In the different figures, the same references designate identical or similar elements.

[0051] In [Fig.1], a VHL vehicle is schematically represented, with a front axle AV with steering and driving wheels and a rear axle ARR with selectively driven wheels (in so-called '4x4' mode).

[0052] The vehicle in question may be a passenger vehicle, a utility vehicle, a van, a recreational vehicle, a minibus, a coach, a truck, etc.

[0053] The front axle is powered by a first electric motor unit. The first electric motor unit is equipped with a first electric machine, denoted ME1, and includes a first three-phase transmission.

[0054] The first electric machine ME1 is engaged with the wheel shafts 21G,21D of the front axle via the first TRI transmission.

[0055] As known in itself and not described in detail, the first TRI transmission includes a differential and a reducer which allows the rotational speed to be lowered from the rotational speed of the electric machine noted col to the rotational speed of the front wheel shafts 21G,21D.

[0056] A first transmission ratio RI is thus determined between col and the rotation speed of the front wheel shafts 21G,21D, so that the rotation speed of the differential ring is equal to RI x col, also noted in compact form Rlcol.

[0057] The front axle electromotor unit may, where appropriate, include an internal combustion engine (in the case of a hybrid vehicle).

[0058] The rear axle is powered by a second electric motor unit. This second electric motor unit is equipped with a second electric machine, designated ME2, and includes a second transmission, TR2.

[0059] The second electric machine ME2 is in selective engagement with the wheel shafts 22G,22D of the front axle via the second transmission TR2.

[0060] As known in itself and not described in detail, the second transmission TR2 includes a differential and a reducer which allows the rotational speed to be lowered from the rotational speed of the electric machine denoted co2 down to the rotational speed of the rear wheel shafts 22G,22D.

[0061] A second transmission ratio R2 is thus determined between co2 and the rotational speed of the rear wheel shafts 22G,22D, so that the rotational speed of the differential ring is equal to R2 x co2, also noted in compact form R2co2.

[0062] In the normal case, the front axle rotates at the same speed as the rear axle, so we have substantially Rlcol= R2co2.

[0063] This is also true in curves where the differential is used, even if the outside wheels turn faster than the inside wheels, the above equality remains true at the level of the differential rings.

[0064] The first electric machine ME1 is driven by a first control unit UCE1 via a power device called an inverter INV1 (or 'inverter' in industry jargon), which includes power switches connected to the stator phases. The first control unit is referred to herein as the first motor control unit.

[0065] Similarly, the second electric machine ME2 is controlled by a second control unit UCE2 via a power device called inverter INV2.

[0066] In addition, a supervisory unit, also called a SUP supervisor, is planned, configured to coordinate the needs for positive motor control and regenerative braking.

[0067] To communicate with each other, it is planned that the first control unit UCE1, the second control unit UCE2, the supervisor computer SUP and the battery management computer 13 will communicate via a multiplexed network 15, for example a CAN type network, as known per se.

[0068] The CAN network data rate is at least 500 kilobits / s. In practice, a CAN network with a data rate of 1 megabit / s can be used. If necessary, a private multiplexed network can be used to avoid any latency in the transmission of messages from the ASR computer to the engine control unit.

[0069] The vehicle is equipped with a BATT battery, also known as a traction battery or battery pack. The electrochemical technology of the battery can be any type within the meaning of the present invention. It could, for example, be lithium-ion technology.

[0070] As known in itself, a battery management computer 13 is provided, otherwise known in the trade as BMS from the English 'Battery Management System', the functions of which are not detailed here.

[0071] Although [Fig.1] illustrates a configuration with two electrically powered axles, the present invention also applies to a configuration with a single electrically powered axle.

[0072] The vehicle is equipped with a dynamic stability control system noted ESP including at least one traction control function.

[0073] Moreover, generally, the dynamic stability control system includes, as is known in itself, an anti-lock braking system (ABS) function.

[0074] For the traction control function, the ESP dynamic stability control system acts on the electric motor groups if there are two or on the electric motor group if there is only one.

[0075] We are particularly interested here in the anti-slip function, this function consisting of reducing the torque (tractor or resistor, i.e. positive or negative) applied to the wheels by the electro-motor unit in the event that the adhesion between the tire and the ground proves insufficient.

[0076] As a reminder, the present invention relates to traction control (called in the trade ASR) and engine braking traction control (called in the trade MSR), and the computer in charge of these functions is called the ASR computer for the sake of brevity.

[0077] As illustrated in [Fig.2], the ESP dynamic stability control system acquires signals from the four wheel speed sensors, one on each wheel.

[0078] This information is noted as VRARG, VRARD, for the left and right rear wheel signals respectively, and VRAVG, VRAVD for the left and right front wheel signals respectively.

[0079] As illustrated in [Fig.2], the ASR computer also acquires information from a 3-axis acceleration sensor denoted 31 and a steering angle sensor denoted 32.

[0080] Furthermore, block 30 represents the driver's intent, which may, depending on the circumstances, originate directly from the accelerator pedal. In other driving situations, a command issued by a driver assistance system such as cruise control is also considered equivalent to the driver's intent; in this case, the command is no longer directly linked to the position of the accelerator pedal.

[0081] The engine torque command resulting from the driver's intention is noted TTL.

[0082] Advantageously according to the present invention, the ASR computer continuously calculates a reference speed and generates, as a function of this reference speed, on the one hand a lower limit of rotational speed of a reference shaft of the electromotor group and on the other hand an upper limit of rotational speed of the reference shaft of the electromotor group.

[0083] According to an example implementation, the output shaft of the electric machine in the considered electromotor set is chosen as the reference shaft, namely, in practice, the shaft that carries the rotor. It should be noted that the electric machine includes as a basic component a sensor that measures the position and speed of the rotor shaft.

[0084] For the first electromotor group, the motor control unit UCE1 receives from the ASR computer the lower limit noted colmin and the upper limit noted colmax.

[0085] Similarly, for the second electromotor group, the UCE2 motor control unit receives from the ASR computer the lower limit noted co2min and the upper limit noted co2max.

[0086] If the current rotational speed of the reference shaft (col resp. co2) becomes greater than the upper rotational speed limit (colmax resp. co2max), the drive control unit (UCE1 or respectively UCE2) reduces the tractor torque applied to the electric machine ME1 (or respectively ME2).

[0087] Similarly, if the current rotational speed of the reference shaft (col resp. co2) becomes less than the lower rotational speed limit (colmin resp. co2min), the motor control unit (UCE1 or respectively UCE2) reduces the resisting torque to the electric machine ME1 (or respectively ME2).

[0088] The proposed process therefore uses the following basic loop:

[0089] 1- acquisition, by the dynamic stability control system, (in this case the ASR computer) of the wheel rotation speed of each of the wheels of the driven axle, 1b- calculation of the reference speed of the vehicle, 2- generation by the dynamic stability control system (in this case the ASR computer) of a lower rotation speed limit and an upper rotation speed limit of a reference shaft of the electric motor group, 3- transmission of the lower rotation speed limit and the upper rotation speed limit, from the dynamic stability control system (in this case the ASR computer) to the drive control unit, 4- reduction of engine torque, by the drive control unit, if the current rotation speed of the reference shaft becomes greater than the upper rotation speed limit or if the current rotation speed of the reference shaft becomes less than the lower rotation speed limit.

[0090] The basic loop of these steps is executed iteratively with a recurrence frequency of at least 100 Hz, preferably at least 200 Hz. This results in remarkable responsiveness, preventing early transient runaway of a slipping wheel. The comfort and safety of the driver and vehicle occupants are improved. Furthermore, tire damage is also reduced.

[0091] In [Fig.2], TQS1 designates the torque setpoint calculated by the computer The SUP supervisor computer is responsible for the first electric motor unit and is determined by the driver. TQS2 designates the torque setpoint calculated by the SUP supervisor computer for the second electric motor unit and is determined by the driver.

[0092] TQC1 designates the torque command requested by the ASR computer to the first drive control unit UCE1. TQC2 designates the torque command requested by the ASR computer to the second drive control unit UCE2.

[0093] In [Fig.2], reference 61 designates a set of software functions responsible to implement torque limitation in the UCE1 drive control unit, and reference 62 designates a set of software functions responsible for implementing torque limitation in the second UCE2 drive control unit.

[0094] col denotes the rotational speed of the rotor shaft of the first electric machine ME1. co2 denotes the rotational speed of the rotor shaft of the second electric machine ME2.

[0095] Figure 3 illustrates circumstances where the torque generated by the electric machine is pulling, namely, the generated torque tends to increase the kinetic energy of the vehicle. Figure 3 illustrates a case of starting from a standstill, i.e., the speed is zero at the beginning of the sequence and concerns the first driven axle.

[0096] Curve 41 represents the succession of lower speed limits (colmin resp. co2min) provided by the ASR control unit. Curve 42 represents the succession of upper speed limits (colmax resp. co2max) provided by the ASR control unit.

[0097] Curves 43 and 44 represent over time the rotational speed of the reference shaft in the motorized axle considered.

[0098] Curve 43 illustrates the behavior resulting from wheel speed loss without implementation of the present invention, while curve 44 represents the behavior resulting from wheel speed loss with implementation of the present invention. It can be seen that the surge in rotational speed of the reference shaft between times t1 and t2 has been completely eliminated.

[0099] It is noted that it is the upper limit 42 of rotational speed which is stressed, in these circumstances where the torque generated by the electric machine is tractor.

[0100] Figure 4 illustrates circumstances where the torque generated by the electric machine is resistive, namely the generated torque tends to decrease the kinetic energy of the vehicle.

[0101] Curve 51 represents the succession of lower speed limits provided by the ASR control unit. Curve 52 represents the succession of upper speed limits provided by the ASR control unit.

[0102] Curves 53 and 54 represent over time the rotational speed of the reference shaft in the motorized axle considered.

[0103] Curve 53 illustrates the behavior resulting from wheel speed loss without implementation of the present invention, while curve 54 represents the behavior resulting from wheel speed loss with implementation of the present invention. It can be seen that the dip in the rotational speed of the reference shaft between times t1 and t2 has been completely eliminated.

[0104] It is noted that it is the lower limit 51 of rotational speed which is stressed, in these circumstances where the torque generated by the electric machine is resistive.

[0105] With reference to Figures 3 and 4, the time interval between times t1 and t2 is, in one example, on the order of 10 ms to 30 ms. This is therefore an early intervention that can be described as 'preventive' when compared to the conventional intervention of the traction control function, which has a slightly longer response time.

[0106] The method also provides for the transmission of an anti-slip torque command issued by the dynamic stability control system to the control unit drive, and an execution of said anti-slip torque command by the drive control unit.

[0107] As soon as the anti-slip torque command is issued by the dynamic stability control system's computer and received by the engine control unit, this torque command replaces the torque command initiated by the driver. This results in a reduction of torque (tractor or load). In other words, the anti-slip torque command from the dynamic stability control system temporarily overrides the driver's torque command, providing a very responsive reduction in torque value.

[0108] The rest of the time, under normal conditions, the anti-slip torque setting is neutral and the torque setting resulting from the driver's will prevails.

Claims

Demands

1. A method for reducing the torque of an electric machine in the event of a lack of wheel traction in an electric or hybrid motor vehicle comprising at least one electrically driven axle by means of an electric motor unit, the vehicle comprising a dynamic stability control (ESP) system including at least one traction control function acting on the electric motor unit, the electric motor unit comprising at least one electric machine (ME1) and at least one motor control unit (UCE1) responsible for controlling the torque generated by the electric machine in real time, at least according to a setpoint representing the will of a vehicle driver, the method comprising a basic loop including: 1- acquisition, by the dynamic stability control system, of the wheel rotation speed of each of the wheels of the driven axle,2- Generation by the dynamic stability control system of a lower rotational speed limit and an upper rotational speed limit for a reference shaft of the electromotor set, 3- Transmission of the lower rotational speed limit and the upper rotational speed limit from the dynamic stability control system to the drive control unit, 4- Reduction of motor torque by the drive control unit if the current rotational speed of the reference shaft becomes greater than the upper rotational speed limit or if the current rotational speed of the reference shaft becomes less than the lower rotational speed limit.

2. A method according to claim 1, characterized in that the basic loop is executed iteratively with a recurrence frequency of at least 100 Hz, preferably of at least 200 Hz.

3. A method according to any one of claims 1 to 2, characterized in that the dynamic stability control system calculates a reference speed, namely an instantaneous longitudinal displacement speed of the vehicle, in order to generate the lower and upper limits of rotational speed, the reference speed being derived from the instantaneous rotational speeds of each of the vehicle's wheels, and optionally also to information delivered by at least one longitudinal acceleration sensor.

4. A method according to any one of claims 1 to 3, characterized in that the reference shaft of the electromotor set is an output shaft of the electric machine.

5. A method according to any one of claims 1 to 4, characterized in that in circumstances where the torque generated by the electric machine is pulling, namely tending to increase the kinetic energy of the vehicle, it is the upper limit of rotational speed that will be stressed.

6. A method according to any one of claims 1 to 4, characterized in that in circumstances where the torque generated by the electric machine is resistive, namely tending to decrease the kinetic energy of the vehicle, it is the lower limit of rotational speed that will be stressed.

7. A method according to any one of claims 1 to 6, characterized in that the dynamic stability control system communicates with the drive control unit via a CAN data bus with a throughput of at least 500 kilobits / s.

8. A method according to any one of claims 1 to 7, further comprising a transmission of an anti-slip torque command issued by the dynamic stability control system to the drive control unit, and an execution of said anti-slip torque command by the drive control unit.

9. Electric or hybrid motor vehicle, comprising at least one electrically powered axle by means of an electric motor unit, a dynamic stability control (ESP) system including at least one traction control function acting on the electric motor unit, the electric motor unit comprising at least one electric machine (ME1) and at least one drive control unit (UCE1) responsible for controlling the torque generated by the electric machine in real time, the drive control unit being configured to implement the method according to any one of claims 1 to 8.

10. Electric or hybrid motor vehicle, comprising a first axle electrically powered by a first electric motor unit and a second axle electrically powered by a second electric motor unit, a dynamic stability control (ESP) system including at least one anti-slip function acting on the first and second electromotor groups, the first electromotor group comprising at least one first electric machine (ME1) and at least one first motor control unit (UCE1) responsible for controlling the torque generated by the first electric machine in real time, the second electromotor group comprising at least one second electric machine (ME2) and at least one second motor control unit (UCE2) responsible for controlling the torque generated by the second electric machine in real time, the first motor control unit and the second motor control unit being configured to implement the method according to any one of claims 1 to 8.

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