Electric or hybrid vehicle propulsion system

Abstract

Hybrid or electric vehicle propulsion system, comprising: - a primary propulsion subsystem comprising: a primary axle (2) adapted to be connected to primary wheels (10R, 10L) of the vehicle, and a propulsion source (14, 22) for these primary wheels (10R, 10L), this propulsion source being a primary rotating electric machine and / or a thermal machine, - a secondary propulsion subsystem comprising: a secondary axle (1) adapted to be connected to secondary wheels (3R, 3L) of the vehicle, a secondary rotating electric machine (8) for propelling the secondary wheels (3R, 3L) of the vehicle, a reduction gear (7) disposed in the torque path between the secondary rotating electric machine (8) and the secondary wheels (3R, 3L) of the vehicle, a selective torque transmission interruption device (6) in the torque path, this device having an open position and a closed position,The propulsion system also includes a control unit configured to, when a failure of the secondary rotating electrical machine (8) is detected while the selective torque transmission interrupter (6) is in the closed position: - control the primary wheel drive source (14, 22) and / or a braking system for the primary (10R, 10L) and / or secondary (3R, 3L) wheels of the vehicle so that the torque transmitted by the selective torque transmission interrupter (6) is within a predefined range containing the value 0, and - control the opening of the selective torque transmission interrupter (6). (Shorthand figure: Fig. 4)

Description

Title of the invention: Electric or hybrid vehicle propulsion system

[0001] The present invention relates to an electric or hybrid vehicle propulsion system.

[0002] In a known manner, such a propulsion system comprises:

[0003] - a secondary axle connected to secondary wheels of the vehicle,

[0004] - a rotating electric machine for secondary propulsion of the secondary wheels of the vehicle, and

[0005] - a reducer arranged in the torque path between the electric machine secondary rotating wheel and the secondary wheels of the vehicle.

[0006] For safety reasons, it is necessary to be able to disconnect the secondary rotating electrical machine in the event of its failure. For this purpose, it is known to interpose a member for selectively interrupting the torque transmission in the torque path, such as a clutch or a dog clutch. This interruption of torque transmission must be able to take place despite the torque still being transmitted.

[0007] There is a need to remedy the drawback just mentioned.

[0008] The invention aims to meet this need and achieves this, according to one of its aspects, using a hybrid or electric vehicle propulsion system, comprising:

[0009] - a primary propulsion subsystem comprising: a primary axle capable of being connected to primary wheels of the vehicle, and a propulsion source for these primary wheels, this propulsion source being a primary rotating electric machine and / or a thermal machine,

[0010] - a secondary propulsion subsystem comprising: a secondary axle capable of be connected to secondary wheels of the vehicle, a secondary rotating electrical machine for propelling the secondary wheels of the vehicle, a reducer arranged in the torque path between the secondary rotating electrical machine and the secondary wheels of the vehicle, a member for selectively interrupting the transmission of torque in the torque path, this member having an open position and a closed position,

[0011] the propulsion system also comprising a control unit configured to, when a failure of the secondary rotating electrical machine is detected while the selective torque transmission interruption member is in the closed position:

[0012] - control the propulsion source of the primary wheels and / or a system of braking the primary wheels and / or the secondary wheels of the vehicle so that the torque transmitted by the selective torque transmission interruption member is within a predefined range of values ​​containing the value 0, and

[0013] - control the passage to the open position of the selective interruption member of the torque transmission.

[0014] According to the invention, it is ensured that in the event of failure of the secondary rotating electrical machine, this secondary rotating electrical machine can be disconnected from the wheels of the vehicle despite the drag torque exerted on these wheels by the secondary electrical machine. This thus meets the aforementioned safety requirement.

[0015] In the case where the member for selectively interrupting the torque transmission is functionally arranged upstream of the reducer, i.e. between the rotating electrical machine and the reducer, this predefined range of values ​​is for example between -2 Nm and 2 Nm. In another example, the predefined range of values ​​is between -10 Nm and 10 Nm, or even between -20 Nm and 20 Nm, or even between -30 Nm and 30 Nm. This predefined range of values ​​is not necessarily centered on 0.

[0016] The aforementioned reducer may or may not constitute a gearbox, which can allow several ratios to be obtained.

[0017] Where appropriate, once this disconnection has been carried out, the vehicle can continue to be driven exclusively by the propulsion source of the primary wheels, for example in a mode called “refuge mode” or “limp home” in English.

[0018] The control of the propulsion source of the primary wheels and / or of the braking system of the primary wheels and / or of the secondary wheels of the vehicle is for example carried out so as to control a deceleration of the vehicle. The failure of the secondary rotating electrical machine causes for example the short-circuiting of the phases of its stator, and the deceleration control of the vehicle can be determined as a function of the drag torque applied by the secondary rotating electrical machine when the phases of its stator are short-circuited.

[0019] The control unit can be configured to:

[0020] - determine the value of the drag torque applied by the electric machine secondary rotating on the basis of information representative of the vehicle speed,

[0021] - determine on the basis of this value of the drag torque the value of the torque applied to the wheels of the vehicle by the secondary rotating electrical machine,

[0022] - determine on the basis of this value of the torque applied to the wheels of the vehicle by the secondary rotating electrical machine a compensation torque setpoint value for the deceleration of the vehicle and,

[0023] - distribute the compensation torque setpoint between the braking system and the propulsion source of the primary propulsion subsystem.

[0024] The distribution of the compensation torque setpoint between the braking system and the propulsion source of the primary propulsion subsystem can take any value between 0% and 100%, limits included.

[0025] The value of the torque applied to the wheels of the vehicle by the secondary rotating electrical machine is for example determined on the basis of the value of the drag torque by dividing the value of the drag torque by the moment of inertia of the inertia modeling, from the secondary rotating electrical machine, the upstream of the member for selectively interrupting the torque transmission, then using the transmission ratio applied by the reducer taking into account the ratio engaged between this member for selectively interrupting the torque transmission and the wheels, and using the radius of the wheels.

[0026] When the compensation torque setpoint is lower than a threshold value, the compensation torque setpoint is for example only applied to the propulsion source of the primary propulsion subsystem. When this threshold value is exceeded, the braking system can also be used, part of the compensation torque setpoint then being allocated to it.

[0027] The determination of the value of the compensation torque setpoint for the deceleration of the vehicle on the basis of the value of the torque applied to the wheels of the vehicle is done for example in an open loop, which makes it possible to simplify the control.

[0028] Alternatively, this determination of the compensation torque setpoint value for vehicle deceleration based on the value of the torque applied to the vehicle wheels is done, for example, in a closed loop. In this case, the control unit determines, for example, the compensation torque setpoint value by:

[0029] - comparing a deceleration instruction determined on the basis of this value of the torque applied to the vehicle wheels by the secondary rotating electrical machine with an effective deceleration value determined on the basis of information representative of the vehicle speed, and

[0030] - applying the value of this comparison to a corrector providing as output the compensation torque setpoint.

[0031] Such closed-loop control can take into account the friction applied to the vehicle, by the slope of the road, external aerodynamic forces or internal friction in the propulsion system.

[0032] The corrector is for example of the proportional, proportional-integral or proportional-integral-derivative type.

[0033] As a further variant, the determination of the value of the torque setpoint of com- compensation for vehicle deceleration can be done by adding:

[0034] - the setpoint value determined in open loop, calculated only on the based on the value of the torque applied to the vehicle's wheels, and

[0035] - the setpoint value determined in closed loop, for example as obtained above.

[0036] In all of the above, controlling the passage to the open position of this member for selectively interrupting the torque transmission may consist of acting on an actuator moving this member for selectively interrupting the torque transmission from the open position to the closed position. Alternatively, controlling the passage to the open position of this member for selectively interrupting the torque transmission may consist of acting on an actuator holding the member for interrupting the torque transmission, so that it stops its force, for example by interrupting its electrical power supply. An elastic return system such as a spring may then bring the member for selectively interrupting the torque transmission to the open position.

[0037] In all of the above, the member for selectively interrupting the torque transmission may be a dog clutch or a clutch. It is preferably a dog clutch.

[0038] The control unit may comprise:

[0039] - a first control module configured to detect the failure of the secondary rotating electrical machine and, where appropriate, to control the passage to the open position of the selective interruption member of the torque transmission, and

[0040] - a second control module configured to control the source of propulsion of the primary wheels and / or the braking system of the primary wheels and / or the secondary wheels of the vehicle so that the torque transmitted by the selective torque transmission interruption member is within a predefined range of values ​​containing the value 0, and where appropriate to control the transition to the open position of the selective torque transmission interruption member.

[0041] The first control module can also, after having detected the failure of the secondary rotating electrical machine, command the latter to switch to a safety configuration, this configuration involving for example the short-circuiting of the phases of its stator, as already mentioned.

[0042] The command to move the selective transmission interruption member to the open position may be requested before the command of the propulsion source of the primary wheels and / or the braking system to reduce the torque transmitted by the selective torque transmission interruption member, and this command to move to the open position may be maintained until this change can occur, i.e. as soon as the value of the torque transmitted by the selective torque transmission interruption member is within the range of values predefined.

[0043] As already mentioned, the control of the transition to the open position of the selective interruption member of the torque transmission is for example carried out by the first control module or by a second control module. Each of this first and this second control module can, depending on the configuration, carry out this control.

[0044] The first control module is for example integrated into the secondary propulsion subsystem, being in particular a control module for the inverter / rectifier supplying the secondary rotating electrical machine, and the second control module may be external to the primary propulsion subsystem and to the secondary propulsion subsystem.

[0045] The first control module may alternatively be integrated into the actuator of the selective torque transmission interruption member, this actuator in particular allowing the transition from the open position to the closed position of the selective torque transmission interruption member.

[0046] The second control module is for example integrated into the vehicle's transmission control unit ("TCU" in English) or into the engine control unit ("ECU" in English) or into another separate control unit for example a vehicle control unit, called (Vehicle Control Unit, VCU in English).

[0047] Each of the first and second control modules implements, for example, one or more digital processing devices, such as microcontrollers. Each control module is, for example, an ASIC type integrated circuit (“Application-specific integrated circuit” in English).

[0048] In all of the above, the member for selectively interrupting the torque transmission may be arranged upstream of the reducer, or downstream of the reducer, or in the reducer, then selectively connecting two shafts of this reducer. "Upstream" and "downstream" must be understood in relation to the torque path generated by the secondary rotating electrical machine.

[0049] The secondary axle may be the front axle or the rear axle of the vehicle.

[0050] The secondary rotating electrical machine may have a nominal electrical power greater than or equal to 5 kW, 15 kW, 25 kW, 50 kW, 100 kW or 300 kW.

[0051] The secondary rotating electrical machine may be a synchronous machine or an asynchronous machine. The electrical machine has, for example, a nominal supply voltage of 48V, or a nominal supply voltage greater than 200V, in particular 300V, in particular 400V, in particular 800V.

[0052] The rotor may be a permanent magnet rotor. The rotor is, for example, devoid of an electrical excitation winding. The rotor may be formed by a stack of laminations with inside which the permanent magnets are arranged.

[0053] Alternatively, the rotor may have an electrical excitation winding.

[0054] The propulsion source of the primary subsystem is for example a rotating electrical machine which may be of the same type as that of the secondary subsystem, or differ from it for example by its nominal electrical power, the presence of permanent excitation at the rotor, or the way in which this permanent excitation is carried out, for example with an electrical excitation winding while the excitation of the rotor of the secondary rotating electrical machine is carried out using permanent magnets, or vice versa.

[0055] Alternatively, the propulsion source of the primary subsystem is a thermal machine.

[0056] As a further variant, the propulsion source of the primary subsystem is hybrid, a thermal machine and a primary rotating electrical machine then being present.

[0057] The secondary rotating electrical machine is for example a permanent magnet synchronous machine and the primary rotating electrical machine is for example a rotor synchronous machine having an electrical excitation winding.

[0058] The invention also relates, according to another of its aspects, to a method for controlling a hybrid or electric vehicle propulsion system, comprising:

[0059] - a primary propulsion subsystem comprising: a primary axle capable of being connected to primary wheels of the vehicle, and a propulsion source for these primary wheels, this propulsion source being a primary rotating electric machine and / or a thermal machine,

[0060] - a secondary propulsion subsystem comprising: a secondary axle capable of be connected to secondary wheels of the vehicle, a secondary rotating electrical machine for propelling the secondary wheels of the vehicle, a reducer arranged in the torque path between the secondary rotating electrical machine and the secondary wheels of the vehicle, a member for selectively interrupting the transmission of torque in the torque path, this member having an open position and a closed position,

[0061] method in which:

[0062] - a failure of the secondary rotating electrical machine is detected while the selective torque transmission interruption member is in the closed position,

[0063] - the selective interruption member is controlled to move to the open position of torque transmission, and

[0064] - the propulsion source of the primary wheels and / or a system of braking of the primary wheels and / or secondary wheels of the vehicle so that that the torque transmitted by the selective torque transmission interruption member is within a predefined range of values ​​containing the value 0, so that this selective torque transmission interruption member in the torque path passes into the open position.

[0065] All or part of the above still applies to the method, in particular the fact that the control is carried out by a control unit as mentioned above.

[0066] More precisely:

[0067] - the control of the propulsion source of the primary wheels and / or of the system of braking of the primary wheels and / or secondary wheels of the vehicle can be carried out so as to command a deceleration of the vehicle, the failure of the secondary rotating electrical machine causing the short-circuiting of the phases of its stator and the deceleration command of the vehicle can be determined according to the drag torque applied by the secondary rotating electrical machine when the phases of its stator are short-circuited,

[0068] - a control unit of an inverter / rectifier electrically supplying the secondary rotating electrical machine can detect the failure of the secondary rotating electrical machine and, if necessary, control the transition to the open position of the selective interruption member of the torque transmission, and a centralized control unit of the vehicle can control the propulsion source of the primary wheels and / or the braking system of the primary wheels and / or the secondary wheels of the vehicle so that the torque transmitted by the selective interruption member of the torque transmission is included in a predefined range of values ​​containing the value 0, and control if necessary the transition to the open position of the selective interruption member of the torque transmission.

[0069] The invention may be better understood by reading the following description of non-limiting examples and by examining the attached drawing in which:

[0070] [Fig-1] schematically represents a vehicle propulsion system hybrid in which the invention can be implanted,

[0071] [Fig.2] represents a curve providing the drag torque exerted by the secondary rotating electrical machine as a function of the speed when the phases of its stator are short-circuited.

[0072] [Fig.3] is a block diagram of how several components of the propulsion system of [Fig.l] interact when implementing an example of control according to the invention,

[0073] [Fig.4] is a block diagram representing several control variants according to the invention, and

[0074] [Fig.5] is a timing diagram representing different steps during the implementation of an example of control according to the invention.

[0075] [Fig.l] shows a propulsion system in which the invention can be implemented. This system can belong to an electric or hybrid vehicle. In the example considered, but in a non-limiting manner, the propulsion system is hybrid, as will be seen later.

[0076] This system here presents a primary subsystem which will be described.

[0077] This primary subsystem comprises a primary axle 2, which is for example the front axle. This primary axle 2 is here associated via a part 1 IR with a primary right wheel 10R and via a part 1 IL with a primary left wheel 10L. This primary axle 2 is here associated with a differential 12 and a reducer 13. This reducer 13 can constitute a gearbox, defining several ratios.

[0078] In the example considered, this primary subsystem is hybrid in that it receives torque from a primary rotating electrical machine 14, the latter being able to be powered through an inverter / rectifier 15 by a battery 16 which in the example considered has a nominal voltage greater than 300V, for example 400V or 800V, but which could alternatively have a lower nominal voltage, for example 48V. This battery 16 is for example supervised by a BMS 17 type system (“battery management system” in English). An angular displacement sensor 27 for the rotor of the primary rotating electrical machine 14 is provided here. The primary rotating electrical machine 14 is for example a synchronous machine with a rotor with an electrical excitation winding.

[0079] This primary subsystem is also hybrid in that it receives torque from a thermal machine 22, where appropriate via a torsional oscillation damper 21 using springs and / or a pendulum damping device, for example. A speed sensor 23 is for example associated with the thermal machine 22. Speed ​​sensors 28R and 28L may also be associated with the primary wheels 10R and 10L.

[0080] The primary subsystem thus presents in the example considered a source of propulsion of the primary wheels 10R and 10L formed by the union of the primary rotating electrical machine 14 and the thermal machine 22.

[0081] In examples not shown, the primary subsystem 2 is purely electrical or purely thermal.

[0082] The secondary subsystem is here arranged on the rear side of the vehicle. In this example, it comprises the rear axle 1 of the vehicle, this rear axle 1 being called the “secondary axle” and being associated via a part 4R with a secondary right wheel 3R and via a part 4L with a secondary left wheel 3L. This secondary axle 1 is here associated with a differential 5 and a reducer 7. This reducer 7 receives torque from a secondary rotating electrical machine 8 powered via an inverter / rectifier 9 from the battery 16 already mentioned. In a variant, two different batteries can be present, one being dedicated to the electrical supply of the secondary rotating electrical machine 8 via the inverter / rectifier 9, the other being dedicated to the electrical supply of the primary rotating electrical machine 14 via the inverter / rectifier 15. The secondary rotating electrical machine 8 is for example a permanent magnet synchronous machine.

[0083] It can be seen in [Fig.l] that the on-board network of the vehicle comprises a high voltage part 20, by which the battery 16 is in the example considered connected to each inverter / rectifier 15, 9 and a low voltage part 19 connected to the high voltage part 20 by means of a DC / DC converter 18. This low voltage part 19 here comprises a battery 44 which has for example a nominal voltage of 12V.

[0084] Similar to the position sensor 27 and the speed sensors 28R, 28L and 23, the secondary axle 1 is associated with an angular displacement sensor 26 for the rotor of the secondary rotating electrical machine 8 and with speed sensors for the wheels 3R ​​and 3L. A speed sensor 27 is also provided on the output of the reducer 7 on the differential 5 side.

[0085] In a known manner, the vehicle also comprises all or part of the various members 42 below, such as a user interface for starting the vehicle 33, such as a button, a handbrake 34, an accelerator pedal 35 and its associated sensor 36, a steering wheel 37, a brake pedal 39 and its associated sensor 38, and a gear lever 41.

[0086] The vehicle also comprises several control units 29, 30, 31 and 32, namely:

[0087] - the vehicle control unit 32, also called VCU (“vehicle control unit” in English. This control unit manages the torque demand from the driver and distributes it between the front and rear propulsion sources 8, 14 and 22. It can also manage the use of the energy available in the propulsion system due to recuperation operation or when charging the battery 16 by the thermal engine 22.

[0088] - the engine control unit 29, for controlling the thermal machine 22,

[0089] - the brake control unit 30,

[0090] - the transmission control unit 31, controlling in particular the reducer 13 of primary axle 2.

[0091] According to the invention, a member for selectively interrupting the torque transmission 6 is present. This member for selectively interrupting the torque transmission 6 is here arranged at the output of the reducer 7, but the invention is not limited to such a location. This member for selectively interrupting the torque transmission 6 may alternatively be arranged at the input of the reducer 7, or inside the reducer 7, then selectively connecting two shafts of this reducer 7.

[0092] This selective torque transmission interruption member 6 has an open position in which it interrupts the torque transmission to the secondary wheels 3R ​​and 3L, and a closed position in which this torque transmission to the secondary wheels 3R ​​and 3L is effective. The modification of the position of this selective torque transmission interruption member 6 is caused at least in one direction by an actuator. The transition from the closed position to the open position is carried out for example via the actuator.

[0093] The member for selectively interrupting the torque transmission 6 is, for example, a clutch or a dog clutch. Preferably, it is a member for selectively interrupting the torque transmission implementing an obstacle transmission, for example via a spline or a toothing, such as a dog clutch.

[0094] The invention makes it possible to ensure that the transition of the selective torque transmission interruption member 6 to the open position occurs in the event of failure of the secondary rotating electrical machine 8.

[0095] For this purpose, the invention uses a control unit which will now be described, in particular with reference to [Fig.3].

[0096] This control unit is in the example considered constituted by:

[0097] - a first control module configured to detect the failure of the secondary rotating electrical machine 8 and, where appropriate, to control the passage to the open position of the selective interruption member of the torque transmission 6, and

[0098] - a second control module configured to control the source of propulsion 14, 22 of the primary wheels 10R and 10L and / or the braking system of the primary wheels and / or the secondary wheels of the vehicle so that the torque transmitted by the selective torque transmission interruption member 6 is within a predefined range of values ​​containing the value 0, and where appropriate to control the transition to the open position of the selective torque transmission interruption member 6.

[0099] In the example of [Fig. 3], the first control module is the control module 50 of the inverter / rectifier 9, and the second control module is the vehicle control unit 32 (VCU). Other embodiments are possible.

[0100] As already mentioned, the first control module 50 detects here according to a step 100 that a failure of the secondary rotating electrical machine 8 occurs. This failure is for example a breakdown of a position measuring element, current measuring element, temperature measuring element, or the interruption of the electrical supply of the machine. This failure can cause a safety shutdown of this secondary rotating electrical machine 8 by the first control module. command 50 during a step 101, this safety being carried out for example by short-circuiting the phases of its stator by action on the switches of the inverter / rectifier 9. In such a configuration, the secondary rotating electrical machine 8 exerts a drag torque on the wheels of the vehicle which changes according to the speed, as shown in [Fig.2].

[0101] The first control module 50 informs, for example, according to a step 102, the second control module 32 of the safety of the secondary rotating electrical machine 8 by sending sequences of non-updated cyclic ratios, by a specific CAN message, or otherwise.

[0102] The reception of this information by the second control module 32 corresponds to a step 103. At the end of this step 103, the second control module 32 can command the transition to the open position of the selective interruption member of the torque transmission 6 during a step 104a or 104b. During step 104a, the actuator is powered to move the selective interruption member of the torque transmission 6 from the closed position to the open position. During step 104b, the power supply to the actuator is interrupted, an elastic return member then being able, in the absence of the force exerted by the actuator, to move the selective interruption member of the torque transmission 6 from the closed position to the open position. Due to the presence of the drag torque and its large value, as shown in [Fig.2], this transition from the closed position to the open position does not necessarily occur.

[0103] In a variant, or in addition, the control of the passage to the open position of the selective interruption member of the torque transmission 6 can be carried out by the first control module 50 according to a step 105a or 105b. Step 105b can be similar to step 104b in that the electrical power supply of the actuator can be suspended.

[0104] Concerning step 105a, when the first control module 50 is still operational following the warning to the second control module 32 of the failure of the secondary rotating electrical machine 8, it can power the actuator to move the selective torque transmission interruption member 6 from the closed position to the open position.

[0105] In a variant, the first control module 50, in the absence of communication with the second control module 32, can command the transition to the open position of the selective torque transmission interruption member 6. Similar to steps 104a and 104b, steps 105a and 105b may not allow the transition from the closed position to the open position, due to the drag torque applied by the secondary rotating electrical machine 8 on the wheels of the vehicle.

[0106] During a step 106, the second control module 32 can generate a control of the propulsion source 14, 22 of the primary wheels 10R and 10L and / or of the braking system of the primary wheels and / or of the secondary wheels of the vehicle to decelerate the vehicle. This deceleration makes it possible to bring the value of the torque transmitted by the selective torque transmission interruption member 6 back into a predefined range of values ​​containing the value 0. This step 106 will be described later with reference to [Fig.4].

[0107] During a step 107, once this command according to step 106 has been applied and once the transition to the open position of the selective torque transmission interruption member has been effective, the second control module 32 can control the propulsion source 14, 22 so as to move the vehicle in degraded mode, for example to a garage in a “limp home” mode.

[0108] Step 104a or 104b, or 105a or 105b is for example maintained until the command according to step 106 has made it possible to bring the value of the torque transmitted by the member for selectively interrupting the torque transmission into the predefined range of values ​​containing the value 0.

[0109] Alternatively, steps 104a or 104b or 105a or 105b only take place once step 106 has made it possible to bring the value of the torque transmitted by the member for selectively interrupting the torque transmission into the predefined range of values ​​containing the value 0.

[0110] We will now describe with reference to [Fig.4] several variants of generation by the second control module 32 according to step 106.

[0111] The second control module 32 determines according to a step 200 the value of the drag torque applied by the secondary rotating electrical machine 8 on the basis of information representative of the speed of the vehicle. This representative information is for example provided by a speed sensor or by an observer. This determination is carried out for example using a correlation between speed and drag torque for the secondary rotating electrical machine 8 when the phases of its stator are short-circuited. This correlation is for example specific to the secondary rotating electrical machine 8 considered, or generic to this type of machine. This correlation is for example the curve according to [Fig.2].

[0112] During a step 201, the second control module 32 determines on the basis of this value of the drag torque determined in step 200 the value of the torque applied to the wheels of the vehicle by the secondary rotating electrical machine 8. The transmission ratio applied by the reducer 7 to the drag torque is then taken into consideration for this determination. More precisely, the value of the torque applied to the wheels of the vehicle by the secondary rotating electrical machine 8 is for example determined on the basis of the value of the drag torque by dividing the value of the drag torque by the moment of inertia of the inertia modeling, from the electric machine secondary rotating, upstream of the selective torque transmission interruption member 6, then using the transmission ratio applied by the reducer 7 taking into account the ratio engaged between the selective torque transmission interruption member 6 and the wheels 3R, 3L and using the radius of the wheels 3L, 3R.

[0113] In the example considered, the value of the torque applied to the wheels of the vehicle by the secondary rotating electrical machine 8 during step 201 is used in two different ways.

[0114] This value is on the one hand used by the second control module 32 to determine according to a step 202 a deceleration setpoint for the propulsion source 14, 22 of the primary wheels 10R and 10L and / or the braking system of the primary wheels and / or the secondary wheels of the vehicle to decelerate the vehicle. This deceleration setpoint value is compared to an actual deceleration value determined by the second control module 32 during a step 203 on the basis of the speed of the vehicle. The speed used during step 203 is for example obtained in the same way as the speed used during step 200, for example using the same speed sensor or the same estimator.

[0115] The result of this comparison is then processed in the example considered during step 204 by a corrector which can be of any type, for example proportional, proportional-integral or proportional-integral-derivative. At the output of this corrector, a compensation torque setpoint is obtained for the deceleration of the vehicle for the propulsion source 14, 22 of the primary wheels 10R and 10L and / or the braking system of the primary wheels and / or the secondary wheels of the vehicle, this torque setpoint being obtained in a closed loop.

[0116] This closed-loop compensation torque setpoint is here added to an open-loop compensation torque setpoint directly from step 201.

[0117] The resultant of these two compensation torque instructions is then distributed according to a step 205 between the braking system and the propulsion source of the primary propulsion subsystem 14, 22. Specific instructions are then sent.

[0118] On the one hand:

[0119] - an instruction 206 is sent to the control module 62 of the subsystem of primary propulsion, the latter being for example the inverter / rectifier control module 15 or the engine control unit 29, and

[0120] - an instruction 207 is sent to the brake control unit 30.

[0121] The distribution of the compensation torque setpoint between the braking system and the propulsion source of the primary propulsion subsystem can take any value between 0% and 100%, limits included. For example, when the compensation torque setpoint determined during step 205 is less than a value threshold, the compensation torque setpoint is only applied to the propulsion source of the primary propulsion subsystem. When this threshold value is exceeded, the braking system may also be used, with part of the compensation torque setpoint then being allocated to it.

[0122] The invention is not limited to what has just been described.

[0123] For example, the value of the compensation torque setpoint for the deceleration of the vehicle can be determined only in open loop, that is to say that none of the steps 202, 203 and 204 are carried out, the output of step 201 being directly processed during step 205.

[0124] As a further variant, the value of the compensation torque setpoint for the deceleration of the vehicle can be determined solely in a closed loop, i.e. the output of the corrector used in step 204 is directly processed during step 205.

[0125] Other variants are possible.

Claims

Claims

1. Hybrid or electric vehicle propulsion system, comprising: - a primary propulsion subsystem comprising: a primary axle (2) capable of being connected to primary wheels (10R, 10L) of the vehicle, and a propulsion source (14, 22) for these primary wheels (10R, 10L), this propulsion source being a primary rotating electrical machine and / or a thermal machine, - a secondary propulsion subsystem comprising: a secondary axle (1) capable of being connected to secondary wheels (3R, 3L) of the vehicle, a secondary rotating electrical machine (8) for propelling the secondary wheels (3R, 3L) of the vehicle, a reducer (7) arranged in the torque path between the secondary rotating electrical machine (8) and the secondary wheels (3R, 3L) of the vehicle, a member for selectively interrupting the torque transmission (6) in the torque path, this member having an open position and a closed position,the propulsion system also comprising a control unit configured to, when a failure of the secondary rotating electrical machine (8) is detected while the selective torque transmission interruption member (6) is in the closed position: - control the propulsion source (14, 22) of the primary wheels and / or a braking system of the primary wheels (10R, 10L) and / or the secondary wheels (3R, 3L) of the vehicle so that the torque transmitted by the selective torque transmission interruption member (6) is within a predefined range of values ​​containing the value 0, and - control the transition to the open position of the selective torque transmission interruption member (6).,

2. System according to claim 1, wherein the control of the propulsion source (14, 22) of the primary wheels and / or the braking system of the primary wheels (10R, 10L) and / or the secondary wheels (3R, 3L) of the vehicle is carried out so as to control a deceleration of the vehicle.

3. A system according to claim 2, wherein the failure of the secondary rotating electrical machine causes the phases of its stator to be short-circuited and wherein the deceleration command of the vehicle is determined as a function of the drag torque applied by the secondary rotating electrical machine when the phases of its stator are short-circuited.

4. System according to claim 3, in which the control unit is configured to: - determine the value of the drag torque applied by the secondary rotating electrical machine on the basis of information representative of the speed of the vehicle, - determine on the basis of this value of the drag torque the value of the torque applied to the wheels of the vehicle by the secondary rotating electrical machine, - determine on the basis of this value of the torque applied to the wheels of the vehicle by the secondary rotating electrical machine (8) a compensation torque setpoint value for the deceleration of the vehicle and, - distribute the compensation torque setpoint between the braking system and / or the propulsion source of the primary propulsion subsystem.

5. System according to claim 4, in which the control unit determines the compensation torque setpoint value by: - ​​comparing a deceleration setpoint determined on the basis of the value of the torque applied to the wheels of the vehicle by the secondary rotating electrical machine (8) with an actual deceleration value determined on the basis of the information representative of the speed of the vehicle, and - applying the value of this comparison to a corrector providing the compensation torque setpoint value as output.

6. System according to any one of the preceding claims, in which the control unit comprises a first control module (50) configured to detect the failure of the secondary rotating electrical machine (8) and, if necessary, to control the transition to the open position of the selective interruption member of the torque transmission (6), and a second control module (32) configured to control the propulsion source (14, 22) of the primary wheels and / or the braking system of the primary wheels (10R, 10L) and / or the secondary wheels (3R, 3L) of the vehicle so that the torque transmitted by the selective interruption member of the torque transmission (6) is included in the predefined range of values ​​containing the value 0, and if necessary to control the transition to the open position of the selective interruption member of the torque transmission (6).

7. System according to claim 6, in which the first control module (50) is integrated into the secondary propulsion subsystem, being in particular a control module of the inverter / rectifier supplying the secondary rotating electrical machine, and in which the second control module (32) is external to the primary propulsion subsystem and to the secondary propulsion subsystem.

8. System according to any one of the preceding claims, the member for selectively interrupting the torque transmission (6) being arranged at the upstream input of the reducer (7), or downstream of the reducer (7), or in the reducer (7), then selectively connecting two shafts of this reducer.

9. Method for controlling a hybrid or electric vehicle propulsion system, comprising: - a primary propulsion subsystem comprising: a primary axle (2) capable of being connected to primary wheels (10R, 10L) of the vehicle, and a propulsion source (14, 22) for these primary wheels (10R, 10L), this propulsion source being a primary rotating electrical machine and / or a thermal machine, - a secondary propulsion subsystem comprising: a secondary axle (1) capable of being connected to secondary wheels (3R, 3L) of the vehicle, a secondary rotating electrical machine (8) for propelling the secondary wheels (3R, 3L) of the vehicle, a reducer (7) arranged in the torque path between the secondary rotating electrical machine (8) and the secondary wheels (3R, 3L) of the vehicle, a member for selectively interrupting the torque transmission (6) in the torque path, this member having an open position and a closed position,method in which: a failure of the secondary rotating electrical machine (8) is detected while the selective torque transmission interruption member (6) is in the closed position, the transition to the open position of the selective torque transmission interruption member (6) is controlled, and the propulsion source (14, 22) of the primary wheels and / or a braking system of the primary wheels (10R, 10L) and / or the secondary wheels (3R, 3L) of the vehicle is controlled so that the torque transmitted by the selective torque transmission interruption member (6) is, within a predefined range of values ​​containing the value 0, so that this selective torque transmission interruption member (6) in the torque path moves into the open position.

10. Method according to claim 9, in which the control of the propulsion source (14, 22) of the primary wheels and / or of the braking system of the primary wheels (10R, 10L) and / or of the secondary wheels (3R, 3L) of the vehicle is carried out so as to control a deceleration of the vehicle, the failure of the secondary rotating electrical machine (8) causing the short-circuiting of the phases of its stator and the deceleration control of the vehicle being determined as a function of the drag torque applied by the secondary rotating electrical machine when the phases of its stator are short-circuited.

11. Method according to claim 10, in which a control unit (50) of an inverter / rectifier (9) electrically supplying the secondary rotating electrical machine (8) detects the failure of the secondary rotating electrical machine and, if necessary, controls the transition to the open position of the selective interruption member of the torque transmission (6), and in which a centralized control unit (32) of the vehicle controls the propulsion source (14, 22) of the primary wheels and / or the braking system of the primary wheels (10R, 10L) and / or the secondary wheels (3R, 3L) of the vehicle so that the torque transmitted by the selective interruption member of the torque transmission (6) is included in the predefined range of values ​​containing the value 0, this centralized control unit controlling, if necessary, the transition to the open position of the selective interruption member of the torque transmission (6).

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