METHOD FOR MAKING AN ELECTRIC MOTOR VEHICLE SAFE

Abstract

The invention relates to a method for securing an electric motor vehicle (10) of the 4x4 type, comprising: - a step of measuring a temperature of the front rotating electrical machine (12) and of the rear rotating electrical machine (15), - a step of activating a heat transfer circuit (17) of the front and rear rotating electrical machines (12, 15) when the temperature of a rotating electrical machine (12, 15) exceeds a first temperature threshold, and - in the case where, despite the activation of the heat transfer circuit (17), the temperature of one of the front or rear rotating electrical machines (12, 15), called "overheated rotating electrical machine", becomes higher than a second temperature threshold, - said method comprises a step of switching to a reconfiguration mode of the overheated rotating electrical machine (12, 15).

Description

Title of the invention: METHOD FOR MAKING AN ELECTRIC MOTOR VEHICLE SAFE

[0001] The present invention relates to a method for securing an electric motor vehicle. The invention finds a particularly advantageous application with fully electric four-wheel drive motor vehicles, known as 4x4 type electric vehicles.

[0002] In a manner known per se, a 4x4 type electric vehicle comprises a front wheel set on which is mounted a front rotating electric machine capable of providing traction to the motor vehicle and a rear wheel set on which is mounted a rear rotating electric machine capable of providing traction to the motor vehicle.

[0003] Currently, the monitoring of the temperature of a rotating electrical machine is carried out by measuring the temperature compared to a maximum temperature threshold. If this temperature exceeds the maximum temperature threshold, the overheating rotating electrical machine enters a protection mode according to which the powertrain supervisor restricts the torque of the electric machine in order to avoid any risk of fire.

[0004] The torque is thus restricted to a predetermined value, typically 50Nm, in the case where the electric machine operates in traction mode or to a predetermined energy recovery value, typically -50Nm, in the case where the electric machine operates in current generator mode.

[0005] This restriction results in inconvenience for users due to the reduction in performance of their vehicle. In particular, the restriction to 50Nm at the output of the rotating electrical machine has the consequence of limiting the speed of the vehicle to approximately 15 km / h on a level road.

[0006] The invention aims to effectively remedy this drawback by proposing a method for securing a motor vehicle comprising: - a front wheel set on which is mounted a front rotating electric machine capable of providing traction to the motor vehicle, - a rear wheel set on which is mounted a rear rotating electrical machine capable of providing traction to the motor vehicle, - said method comprising: - a step of measuring a temperature of the front rotating electrical machine and a temperature of the rear rotating electrical machine, - a step of activating a heat transfer circuit of rotating electrical machines front and rear when the temperature of the front rotating electrical machine and / or the temperature of the rear rotating electrical machine exceeds a first temperature threshold, and - in the event that, despite activation of the heat transfer circuit, the temperature of one of the front or rear rotating electrical machines, known as the "overheated rotating electrical machine", becomes higher than a second temperature threshold, the other rotating electrical machine not being overheated, - said method comprises a step of switching to a reconfiguration mode according to which the following is carried out: - a step of stopping the operation of the rotating electrical machine in overheating, and - a step of stopping the sending of torque instructions to the overheating rotating electrical machine and of realizing a torque request from a driver only by a command from the rotating electrical machine which is not overheating.

[0007] The invention thus makes it possible, in the event of overheating of one of the rotating electrical traction machines of the motor vehicle, to reduce the inconvenience of this failure for users by allowing them to continue their journey while minimizing the loss of performance while guaranteeing the safety of users with regard to a risk of fire in the motor vehicle. The invention also has an economical character insofar as it can be implemented solely by adapting the programming of the computers on board the motor vehicle.

[0008] According to an implementation of the invention, in the reconfiguration mode, said method comprises a step of storing a fault code in a memory of a computer of the overheating rotating electrical machine.

[0009] According to an implementation of the invention, in the reconfiguration mode, said method comprises a step of lighting an indicator light on a dashboard and / or displaying a message indicating to users the presence of an operating problem with a rotating electrical machine.

[0010] According to an implementation of the invention, in the reconfiguration mode, said method comprises a step of substituting a standard accelerator pedal map of the rotating electrical machine which is not overheating with a backup accelerator pedal map containing torque values lower than those of the standard accelerator pedal map.

[0011] According to one implementation of the invention, the step of stopping the overheated rotating electrical machine is carried out by controlling an opening of switching elements of an inverter of the overheated rotating electrical machine.

[0012] According to one implementation of the invention, the temperature of the front rotating electrical machine and the temperature of the rear rotating electrical machine are de- terminated at a calibrated frequency.

[0013] According to one implementation of the invention, the temperature of the front or rear rotating electrical machine is calculated from the average of the measurements transmitted by temperature sensors associated with the corresponding rotating electrical machine.

[0014] According to one implementation of the invention, the temperature of the front or rear rotating electrical machine is determined by retaining a maximum temperature received from the temperature sensors associated with the corresponding rotating electrical machine.

[0015] According to an implementation of the invention, said method comprises a step of reauthorizing operation of the overheated rotating electrical machine when its temperature becomes lower than a temperature recovery threshold.

[0016] According to an implementation of the invention, a fault linked to overheating of one of the rotating electrical machines being rehabilitated when the contact is cut, the motor vehicle being authorized to use the two rotating electrical machines during a next start of said motor vehicle.

[0017] The invention will be better understood upon reading the following description and examining the accompanying figures. These figures are given only for illustrative purposes but in no way limit the invention.

[0018] [Fig-1] [Fig.l] is a schematic representation from above of a vehicle at 4x4 type electric vehicle implementing the safety method according to the invention for one of the rotating electrical machines in the event of overheating;

[0019] [Fig.2] [Fig.2] is a diagram of the steps of the safety process according to the invention of one of the rotating electrical machines in case of overheating.

[0020] [Fig.l] shows a motor vehicle 10 comprising a front wheel set 11 on which is mounted a front rotating electrical machine 12 capable of providing traction of the motor vehicle 10, and a rear wheel set 13 on which is mounted a rear rotating electrical machine 15 capable of providing traction of the motor vehicle 10. The rotating electrical machines 12, 15 are associated with speed reducers 18.1, 18.2 making it possible to adapt the very high rotational speed of the electrical machines to the rotational speed of the vehicle wheels. The rear rotating electrical machine 15 may be associated with a device 19 for coupling and decoupling with the wheels of the motor vehicle.

[0021] The rotating electrical machines 12, 15 are electrically connected to a battery 14 from which the electrical machines 12, 15 draw electrical power in a motor operating mode or to which the electrical machines 12, 15 supply electrical power in a generator operating mode.

[0022] A computer of the front rotating electrical machine called MCUF manages the control of the front rotating electrical machine 12. This MCUF computer is housed in a 16.1 inverter of the rotating electrical machine before 12.

[0023] A computer of the rear rotating electrical machine 15 called MCUR manages the control of the rear rotating electrical machine 15. This MCUR computer is housed in the inverter 16.2 of the rear rotating electrical machine 15.

[0024] The powertrain computer called eVCU controls and supervises in particular the MCUF computer of the front rotating electric machine 12 and the MCUR computer of the rear rotating electric machine 15 via a communication network of the motor vehicle 10.

[0025] Each rotating electrical machine 12, 15 is associated with an electrical power converter 16.1, 16.2 called an inverter comprising a plurality of switching elements, generally transistors, in particular of the MOSFET type. Thus, the front rotating electrical machine 12 is associated with the inverter 16.1 and the rear rotating electrical machine 15 is associated with the inverter 16.2.

[0026] When the rotating electrical machine 12, 15 operates in a motor mode, the inverter 16.1, 16.2 transforms the direct electric current from the electric battery of the vehicle and transforms it into polyphase alternating current applied to the phases of the electrical machine 12, 15. This alternating current thus created by the inverter 16.1, 16.2 will then supply the magnetic poles of the stator of the electrical machine 12, 15 in order to cause the rotor thereof to rotate.

[0027] The inverter 16.1, 16.2 varies the rotation speed of the rotor of the electric machine by controlling the frequency of the alternating current. Similarly, the inverter 16.1, 16.2 varies the mechanical torque of the electric machine 12, 15 by controlling the intensity of the alternating supply current of the magnetic poles.

[0028] A system for regulating the temperature of the electrical machines 12, 15 is managed by the vehicle computer eVCU. The computers of the front and rear electrical machines (MCUF and MCUR) send the temperature information over the vehicle's communication network via temperature sensors equipping the electrical machines 12, 15. The eVCU computer receives this information as well as the measurements from the temperature sensors of a heat transfer circuit. Depending on this information, the eVCU computer selectively activates the heat transfer circuit 17 so as to cool or heat the rotating electrical machine(s) 12, 15.

[0029] The various steps of the method of securing one of the rotating electrical machines 12, 15 in the event of overheating are described below, with reference to [Fig. 2].

[0030] The MCUF calculator measures, in a step 100, the temperature of the front rotating electrical machine 12 via several temperature sensors arranged at different locations deemed sensitive on the front rotating electrical machine 12.

[0031] Similarly, the MCUR calculator measures the temperature of the machine rear rotating electric machine 15 via several temperature sensors arranged at different locations deemed sensitive on the rear electric machine 15.

[0032] These MCUF, MCUR calculators receive the temperature values at a calibrated frequency, for example every 10 ms. This measurement frequency can be calibrated differently between the front 12 and rear 17 electrical machines.

[0033] When a rotating electrical machine 12, 15 comprises several temperature sensors, the MCUF computer and the MCUR computer can calculate the temperature of the rotating electrical machine 12, 15 by calculating the average of the measurements transmitted by temperature sensors of the corresponding rotating electrical machine 12, 15. Alternatively, the MCUF, MCUR computers can calculate the temperature of an electrical machine 12, 15 by retaining the maximum temperature received from the temperature sensors of the corresponding rotating electrical machine 12, 15.

[0034] The temperature TMelAV of the front rotating electrical machine 12 is thus monitored by the corresponding computer MCUF. The temperature TMelAR of the rear rotating electrical machine is monitored by the corresponding computer MCUR.

[0035] When the MCUF computer of the front rotating electrical machine 12 detects that the temperature TMelAV exceeds a first temperature threshold SMelAVl, the MCUF computer requests, in a step 101, the eVCU computer to activate the heat transfer circuit 17 of the rotating electrical machines 12, 15.

[0036] Similarly, when the MCUR computer detects that the temperature TMelAR exceeds a first temperature threshold SMelARl, the MCUR computer requests the vehicle computer eVCU to activate the heat transfer circuit 17 of the rotating electrical machines 12, 15.

[0037] These first temperature thresholds SMelAVl and SMelARl are calibratable. The first temperature thresholds SMelAVl and SMelARl depend on the architecture and characteristics of each of the rotating electrical machines 12, 15. These first temperature thresholds SMelAVl and SMelARl are for example calibrated at 45°C but they can be calibrated at different temperatures. From the activation of the heat transfer circuit 17, the temperature of the critical electrical machine 12 or 15 is supposed to decrease.

[0038] However, if the temperature of the front rotating electrical machine 12 or of the rear rotating electrical machine 15 continues to increase despite the request to activate the heat transfer circuit 17 of the electrical machines, a second temperature threshold (SMelAV2 for the front rotating electrical machine 12 and SMelAR2 for the rear rotating electrical machine 15) is reached. These second temperature thresholds SMelAV2 and SMelAR2 are also calibratable.

[0039] The second temperature thresholds SMelAV2 and SMelAR2 depend on the architecture and characteristics of each of the rotating electrical machines 12, 15. The second temperature thresholds SMelAV2 and SMelAR2 are for example calibrated at 55°C but may be calibrated differently between the front and rear rotating electrical machines 12, 15.

[0040] If the temperature TMelAV of the front rotating electrical machine 12 exceeds the second temperature threshold SMelAV2, the MCUF computer of the front rotating electrical machine 12 informs, in a step 102, the eVCU computer of this temperature exceedance. The eVCU vehicle computer then engages, in a step 103, a mode of reconfiguration of the front rotating electrical machine 12 in order to make the front rotating electrical machine 12 safe from the risk of fire.

[0041] Similarly, if the temperature TMelAR of the rear rotating electrical machine 15 exceeds the second temperature threshold SMelAR2, the MCUR computer of the rear rotating electrical machine 15 informs the eVCU computer of this temperature exceedance. The eVCU vehicle computer then engages a reconfiguration mode of the rear rotating electrical machine 15 in order to make the rear rotating electrical machine 15 safe from the risk of fire.

[0042] The mode of reconfiguration of the front rotating electrical machine 12 is described below. The MCUF computer of the front rotating electrical machine 12 stores a fault code in its memory which it transmits to the eVCU computer in order to be able to indicate to an after-sales diagnostic device that the MCUF computer has encountered an overheating problem of the front rotating electrical machine 12.

[0043] The MCUF calculator of the front rotating electrical machine 12 requests the eVCU calculator to illuminate a "Service" type indicator light on the dashboard and / or to display a message indicating to users the presence of an operating problem with a rotating electrical machine 12, 15.

[0044] The MCUF computer of the front rotating electrical machine 12 stops the operation of the front rotating electrical machine 12 by controlling the opening of the switching elements of the inverter 16.1 of the front rotating electrical machine 12 so that it is no longer supplied with current.

[0045] The eVCU computer stops sending torque instructions to the MCUF and carries out the driver's wishes (torque instruction dependent on the accelerator pedal depression) only via torque instructions sent to the MCUR computer of the rear rotating electrical machine 15, as described in more detail below.

[0046] The reconfiguration mode of the rear rotating electrical machine 15 is identical to the reconfiguration mode of the front rotating electrical machine 12.

[0047] The MCUR calculator of the rear rotating electric machine 15 stores a code fault in its memory which it transmits to the eVCU computer in order to be able to indicate to an after-sales diagnostic device that the MCUR computer has encountered an overheating problem of the rear rotating electrical machine 15.

[0048] The MCUR calculator of the rear rotating electrical machine 15 requests the eVCU calculator to illuminate a "Service" type indicator light on the dashboard and / or to display a message indicating to users the presence of an operating problem with a rotating electrical machine 12, 15.

[0049] The MCUR computer of the rear rotating electrical machine 15 stops the operation of the rear rotating electrical machine 15 by controlling the opening of the switching elements of the inverter 16.2 of the rear rotating electrical machine 15 so that the latter is no longer supplied with current.

[0050] The eVCU computer stops sending torque instructions to the MCUR and implements the driver's wishes (torque instruction dependent on the accelerator pedal depression) only via torque instructions sent to the MCUF computer of the front rotating electrical machine 12, as described in more detail below.

[0051] The following describes the change of accelerator pedal mapping in the eVCU computer of the motor vehicle 10.

[0052] The eVCU calculator contains in its memory instructions for controlling the two front and rear electrical machines 12, 15 according to: - a driving mode (Eco, Standard, Sport) selected by the user; - a level of depression of the accelerator pedal by the user; and - a vehicle speed.

[0053] An example of accelerator pedal maps managed by the eVCU computer in economy mode is shown below.

[0054] The accelerator pedal mapping for the front rotating electric machine 12 stored in the eVCU computer is for example as follows: ECO driving mode for the electric machine before when the 2 machines are functional 1101 |ii»l liBi illl MBIi liBl 50 liiii 70 liBii liBi fliil 1®I 0 342 342 342 403 597 790 950 1049 1049 1049 1049 1049 1512 liiii 296 296 296 309 513 722 884 1045 1049 1049 1049 1049 1512 liiii 214 214 214 389 475 680 843 1005 1049 1049 1049 1049 1512 ilBl 62 62 122 326 439 641 803 965 1049 1049 1049 1049 1512 10 23 251 391 585 747 909 1008 1049 1049 1049 1512 ilBl 161 321 504 663 822 935 1023 1049 1049 1512 20 104 397 433 588 744 868 979 1049 1049 1512 Z5 67 327 373 521 673 805 932 1049 1049 1512 30 43 265 319 461 603 745 887 1049 1049 1512 40 43 246 291 417 545 698 829 967 1049 1512 lOii 43 226 399 381 497 645 766 886 963 1512 60 43 207 365 348 455 595 707 803 803 1338 70 43 18S 333 318 415 547 653 688 688 1147 80 Brake motor 43 168 304 293 387 495 596 602 602 1003 90 43 149 280 274 361 448 535 535 535 892 95 41 141 265 392 345 427 507 507 507 845 100 39 134 250 370 330 406 482 482 482 803110 35 122 224 326 295 367 438 438 438 730 120 32 111 202 290 396 333 401 401 401 669 130 30 103 183 260 357 305 371 371 371 617 135 29 99 174 247 340 292 357 357 357 595 140 28 96 166 236 325 281 344 344 344 573 iiSi 26 90 151 214 296 389 321 321 321 535

[0055] The accelerator pedal mapping for the rear rotating electric machine 15 stored in the eVCU computer is for example as follows: ECO driving mode for the rear electric machine when both machines are functional 0 S 1« 20 3Ô 40 50 60 70 $0 ao H0 0 0 0 0 201 299 saq 475 524 524 524 524 524 756 3 0 0 0 ISS 257 361 442 523 524 524 524 524 756 0 0 0 0 238 340 421 502 524 524 524 524 756 ilili 0 0 0 0 220 320 402 482 524 524 524 524 756 10 0 0 195 293 374 454 504 524 524 524 756 15 0 161 252 331 411 468 512 524 524 756 20 0 0 217 294 372 434 489 524 524 756 25 0 0 187 261 337 403 466 524 524 756 30 0 0 159 230 302 373 444 524 524 756 40 0 0 145 208 272 349 415 484 524 756 50 0 0 0 190 249 322 383 443 482 756 60 0 0 0 174 227 297 353 401 401 669 70 0 0 0 159 208 273 326 344 344 574 30 Engine brake 0 0 0 147 193 247 298 301 301 502 90 0 0 0 137 180 224 268 268 268 446 95 0 0 0 0 173 213 254 254 254 423 100 0 0 0 0 165 203 241 241 241 401 110 0 0 0 0 147 183 219 219 219 365 120 0 0 0 0 0 167 201 201 201 335 130 0 0 0 0 0 152 185 185 185 309 135 0 0 0 0 0 146 178 178 178 297 140 0 0 0 0 0 140 172 172 172 287 150 0 0 0 0 0 0 161 161 161 268

[0056] In X is indicated the depression of the accelerator pedal.

[0057] In Y is indicated the speed of the vehicle.

[0058] In Z is indicated the torque setpoint at the wheel requested by the eVCU calculator at the rotating electric machine before 12.

[0059] Thus, for example in standard operation without failure, at 20km / h and 50% depression of the accelerator pedal, the eVCU calculator requests: - to the front rotating electric machine 12 to provide 588Nm of torque to the front wheels, and - to the rear electric machine 15 to supply 294Nm of torque to the rear wheels.

[0060] In this example where neither of the two MCUF and MCUR computers alerts the eVCU computer to overheating of one of the two rotating electric machines 12, 15, the vehicle is propelled by a total torque of 882Nm to the wheels.

[0061] In the case where the rear rotating electrical machine 15 is overheating (TMelAR > SMelAR2), the MCUR computer alerts the eVCU computer of overheating of this rotating electrical machine 15. The eVCU computer then switches to a backup accelerator pedal map to control the front rotating electrical machine 12. This backup accelerator pedal map no longer depends on the driving mode (Eco, standard or sport) selected by the user, insofar as the motor vehicle 10 is in a safe mode.

[0062] The wheel torque values contained in this backup accelerator pedal map are lower than those contained in the standard accelerator pedal map. The values contained in the backup accelerator pedal map, an example of which is given below, are calibratable. safe driving mode for the front electric machine when the rear electric machine is malfunctioning iiioi lf«i liBil iioii illOl i«ii iiOli 80 90 100 iioii 0 171 171 171 302 448 593 713 787 787 787 787 787 1134 148 148 148 232 385 542 663 784 787 787 787 787 1134 5 107 107 107 195 357 510 632 754 787 787 787 787 1134 7 31 31 61 163 330 481 603 724 787 787 787 787 1134 10 126 293 439 561 682 756 787 787 787 1134 81 241 378 497 617 702 768 787 787 1134 2S 52 199 325 441 558 651 734 787 787 1134 25 34 164 280 391 505 604 699 787 787 1134 30 22 133 239 346 453 559 666 787 787 1134 iioii 22 123 218 313 409 524 622 726 787 1134 they 22 113 200 286 373 484 575 665 723 1134 22 104 183 261 341 446 530 602 602 1004 7D 22 94 167 239 312 410 490 516 516 861 80 Brake motor 22 84 152 220 230 371 447 452 452 753 00 22 75 140 206 271 336 402 402 402 669 95 21 71 133 196 259 ICI 145 198 250 301 301 301 502 15 52 92 130 179 229 278 278 278 463 135 15 50 87 124 170 219 268 268 268 446 14014 48 83 118 163 211 258 258 258 430 150 13 45 76 107 148 195 241 241 241 402

[0063] In the case where the front rotating electrical machine 12 is overheating (TMelAV > SMelAV2), the MCUF computer alerts the eVCU computer of overheating of this rotating electrical machine 12. The eVCU computer then switches to a car emergency accelerator pedal mapping for controlling the rear rotating electric machine 15. This emergency accelerator pedal mapping no longer depends on the driving mode (Eco, standard or sport) selected by the user, as long as the motor vehicle 10 is in a safe mode.

[0064] The wheel torque values contained in this backup accelerator pedal map are lower than those contained in the standard accelerator pedal map. The values contained in the backup accelerator pedal map, an example of which is given below, are calibratable. safe driving mode for the rear electric machine when the front electric machine is malfunctioning a IIIIO 114 llfi 114 iüKi 114 ulïü 201 n^fii 299 uïsü 395 Ü^Ü 475 uiuS 524 iulu 524 lui 524 |||gg|| 524 him 524 iiioil 756 llol; 99 99 99 155 257 361 442 523 524 524 524 524 756 s 71 71 71 130 238 340 421 502 524 524 524 524 524 757 21 21 194 220 320 402 482 524 524 524 524 756 10 8 84 195 293 374 454 504 524 524 524 756 15 54 161 252 331 414 264 454 756 35 132 217 294 372 434 489 524 524 756 22 109 187 261 337 403 466 524 524 756 :«) 524 756 40 14 82 145 208 272 349 415 484 524 756 *50 14 75 133 190 249 322 383 44.3 482 756 60 14 69 122 174 227 297 353 401 401 669 70 14 63 111 159 208 273 325 344 344 574 80 Engine brake 14 56 101 147 193 247 298 301 301 502 90 14 50 93 137 180 224 268 268 268 446 ■■ 14 47 88 131 173 213 254 254 254 423 llolî 13 45 83 123 165 203 241 241 241 401 HO 12 41 75 109 147 183 219 219 219 365 130 11 37 67 97 132 167 201 201 201 335 10 34 61 87 119 152 185 185 185 309 10 33 58 82 113 146 178 178 178 297 140 9 32 55 79 108 140 172 172 172 287 ISO 9 30 50 71 99 130 161 161 161 268 .

[0065] After stopping the front rotating electrical machine 12 or rear rotating electrical machine 15, the temperature monitoring remains active on the two rotating electrical machines 12, 15 as long as the driver has not switched off the ignition on the dashboard. The fault is rehabilitated when the temperature measured on the faulty electrical machine 12, 15 becomes lower than a temperature recovery threshold SRAV of the front rotating electrical machine 12 or below a temperature recovery threshold SRAR of the rear rotating electrical machine 15.

[0066] According to an implementation variant, when the contact is cut off, the fault is rehabilitated and the motor vehicle 10 is authorized to start again with the operation of the two rotating electrical machines 12, 15 the next time the motor vehicle 10 is started.

[0067] The conditions for rehabilitation of the defect are as follows: - the MCUx calculator (x can be the letter F or R) stops asking the eVCU calculator to turn on the “Service” indicator light and / or display the message on the dashboard; - the MCUx computer reauthorizes the operation of the electrical machine 12, 15 which presented the fault; and - the fault remains stored in the memory of the eVCU computer and the MCUx computer in order to allow the after-sales network to carry out a fault analysis on the electrical machine 12, 15 affected by the overheating and to decide whether it is necessary to replace a component of the electrical machine 12, 15.

Claims

Claims

1. Method for securing a motor vehicle (10) comprising: - a front wheel set (11) on which is mounted a front rotating electrical machine (12) capable of providing traction of the motor vehicle (10), - a rear wheel set (13) on which is mounted a rear rotating electrical machine (15) capable of providing traction of the motor vehicle (10), characterized in that said method comprises: - a step (100) of measuring a temperature of the front rotating electrical machine (12) and a temperature of the rear rotating electrical machine (15), - a step (101) of activating a heat transfer circuit (17) of the front and rear rotating electrical machines (12, 15) when the temperature of the front rotating electrical machine (12) and / or the temperature of the rear rotating electrical machine (15) exceeds a first temperature threshold (SMelAVl, SMelARl), and - in the case where, despite the activation of the circuit heat transfer fluid (17),the temperature of one of the front or rear rotating electrical machines (12, 15), called the "overheating rotating electrical machine", becomes higher than a second temperature threshold (SMelAV2, SMelAR2), the other rotating electrical machine (12, 15) not being overheated, - said method comprises a step (103) of switching to a reconfiguration mode according to which the following are carried out: - a step of stopping operation of the overheating rotating electrical machine (12, 15), and - a step of stopping the sending of torque instructions to the overheating rotating electrical machine (12, 15) and of carrying out a torque request from a driver solely by controlling the rotating electrical machine (12, 15) which is not overheating.

2. Method according to claim 1, characterized in that, in the reconfiguration mode, said method comprises a step of storing a fault code in a memory of a computer (MCUR, MCUF) of the rotating electrical machine (12, 15) in overheating.

3. Method according to claim 1 or 2, characterized in that in the reconfiguration mode, said method comprises a step of lighting a warning light on a dashboard and / or displaying a message indicating to users the presence of a problem in the operation of a rotating electrical machine (12, 15).

4. Method according to any one of claims 1 to 3, characterized in that in the reconfiguration mode, said method comprises a step of substituting a standard accelerator pedal map of the rotating electrical machine (12, 15) which is not overheated by a backup accelerator pedal map containing torque values lower than those of the standard accelerator pedal map.

5. Method according to any one of claims 1 to 4, characterized in that the step of stopping the overheated rotating electrical machine (12, 15) is carried out by controlling an opening of switching elements of an inverter (16.1, 16.2) of the overheated rotating electrical machine (12, 15).

6. Method according to any one of claims 1 to 5, characterized in that the temperature of the front rotating electrical machine (12) and the temperature of the rear rotating electrical machine (15) are determined at a calibrated frequency.

7. Method according to any one of claims 1 to 6, characterized in that the temperature of the front (12) or rear (15) rotating electrical machine is calculated from the average of the measurements transmitted by temperature sensors associated with the corresponding rotating electrical machine (12, 15).

8. Method according to any one of claims 1 to 6, characterized in that the temperature of the front (12) or rear (15) rotating electrical machine is determined by retaining a maximum temperature received from the temperature sensors associated with the corresponding rotating electrical machine (12, 15).

9. Method according to any one of claims 1 to 8, characterized in that it comprises a step of re-authorizing operation of the rotating electrical machine (12, 15) in overheating when its temperature becomes lower than a temperature recovery threshold (SRAV, SRAR).

10. Method according to any one of claims 1 to 9, characterized in that a fault linked to overheating of one of the rotating electrical machines (12, 15) being rehabilitated during a cut-off of contact, the motor vehicle (10) being authorized to use the two rotating electrical machines (12, 15) during a next start of said motor vehicle (10).

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