DE102019204205A1 - Method for operating a drive system of an electric vehicle and a drive system for an electric vehicle - Google Patents

Abstract

The invention relates to a method for operating a drive system (100) of an electric vehicle, comprising an electric machine (54), an inverter unit (30) for controlling the electric machine (54), which has a torque control unit (32) and a control unit (52), wherein the torque control unit (32) detects an actual speed (40) of the electric machine (54) and a control deviation (46) is calculated from the actual speed (40) of the electric machine (54) and a target speed (62); A regulator (42) of the torque control unit (32) calculates a correction torque (44) from the control deviation (46); a target torque (51) is calculated by the torque control unit (32) from the correction torque (44) and a preset torque (50); a target current (57) is calculated by the control unit (52) from the target torque (51); and the electric machine (54) is controlled by the control unit (52) with the target current (57). The invention also relates to a drive system (100) for carrying out the method for an electric vehicle.

Description

The invention relates to a method for operating a drive system of an electric vehicle, which has a transmission with at least one axle differential of at least one driven axle of the electric vehicle, an electric machine for driving the transmission and an inverter unit for controlling the electric machine, which has a torque control unit and a control unit has, includes. The invention also relates to a drive system for an electric vehicle, which has a transmission with at least one axle differential of at least one driven axle of the electric vehicle, an electric machine for driving the transmission and an inverter unit for controlling the electric machine, which has a torque control unit and a control unit, includes.

State of the art

DE 10 2011 088 729 A1 relates to a speed window-based control strategy for an electric machine. An engine controller is disclosed which is used to control an electric machine, in particular to drive a vehicle. The engine controller comprises an input connection for inputting a torque desired for a torque to be delivered by the electric machine in the indicative desired setpoint values and for inputting a limit value indicative of a mechanical operating limit of the electric machines. Furthermore, the engine control comprises a processor for outputting a torque indicative of a torque actually to be delivered by the electric machine in the actual setpoint, the processor being designed to determine the actual setpoint based on the desired setpoint and the limit variable. The motor control is designed as a converter for converting a direct current into an operating current for the electric machine, the operating current being a particularly three-phase alternating current and the converter being designed so that it generates the operating current based on the actual setpoint.

DE 10 2016 203 113 A1 relates to a control system for distributing drive torque and a vehicle with such a control system. The control system is used to distribute a drive torque between a left and a right drive wheel of a motor vehicle via a differential gear. The drive torque is provided by an electric motor coupled to the differential gear. The drive torque provided is distributed by a speed excitation of the electric motor and an adjustable brake intervention on one of the drive wheels in such a way that, with different coefficients of friction acting on the left and right drive wheels, the drive torque available on the drive wheel with the higher coefficient of friction for a substrate in contact with the drive wheels is higher than on the drive wheel on which the lower coefficient of friction is presented. In this way, an effective propulsive torque is largely transmitted via that of the drive wheels which has the higher coefficient of friction. The invention also relates to a motor vehicle which comprises such a control system. The control system comprises a control device and sensors for detecting the wheel speeds, wheel brakes for individually braking the drive wheels and / or at least one actuator unit for the adjustable actuation of the wheel brakes assigned to the drive wheels.

A device for regulating an engine, in particular a vehicle engine, is from the EP 2 810 132 B1 known.

Vehicles with an electric drive and an axle differential connected to it and provided on a driven axle have very high dynamics with regard to the drive torques that occur. This can lead to very different wheel speeds between the left and right wheels of a driven axle, especially with inhomogeneous coefficients of friction. The resulting high differential speed represents a strong mechanical load on the axle differential of the driven axle. This can damage the axle differential and, in the worst case, lead to a total failure of the drive train. The driving comfort also suffers due to the noises occurring and the vibrations associated with them. A corrective intervention of known wheel control systems z. B. ESP-TCS, comes only after a period of time d. H. belated to take effect. The reason for this is, among other things, long signal transit times, which are also referred to as latencies, between the control units involved in the work chain in the vehicle.

Disclosure of the invention

A method for operating a drive system of an electric vehicle is proposed. The drive system comprises a transmission with at least one axle differential of at least one driven axle of the electric vehicle, an electric machine for driving the transmission and an inverter unit for controlling the electric machine. The inverter unit has a torque control unit and a control unit.

An actual speed of the electrical machine is recorded by the torque control unit. The torque control unit turns the actual speed into the electrical machine and a target speed calculated a control deviation. A correction torque is calculated from the control deviation by a regulator of the torque control unit. A target torque is calculated by the torque control unit from the correction torque and a default torque. A target current is calculated from the target torque by the control unit. The electrical machine is controlled by the control unit with the calculated target current.

In the method according to the invention, a control loop directly in the inverter unit ensures immediate, fast, subordinate speed control of the electrical machine and thus supports an external control loop for controlling the wheel speeds. In this way, excessively high wheel speeds or excessively high differential speeds between the individual driven wheels of a drive axle are avoided right from the start. The subordinate speed control in the inverter unit is now automatically active under certain conditions. Because of the lower differential speeds between the driven wheels as a result, the axle differential in the axle driven by the electric machine is mechanically less stressed.

According to an advantageous embodiment of the invention, the torque control unit has a protection unit. The target speed is calculated by the protection unit.

The target speed can be calculated by the protection unit, for example, from speed signals from all the wheels of the electric vehicle, in particular by averaging.

However, the target speed can also be calculated by the protective unit exclusively from speed signals from wheels of a non-driven axle of the electric vehicle, in particular by averaging.

According to another advantageous embodiment of the invention, the target speed is calculated by a separate ESP system (electronic stability program) and transmitted to the torque control unit of the inverter unit. In this case, a situation-related setpoint speed is transmitted from the ESP system to the inverter unit via a corresponding data interface. The fast, subordinate speed control takes place within the inverter unit. The additional communication effort between the ESP system and the inverter unit remains manageable.

According to a preferred development of the invention, a control mode signal is generated by a separate ESP system and transmitted to the torque control unit of the inverter unit. The control mode signal signals to the inverter unit possible driving states of the electric vehicle, for example free rolling, TCS intervention (Traction Control System), ABS intervention (anti-lock braking system) or DTC intervention (Drag Torque Control).

According to a preferred embodiment of the invention, the specified torque is calculated by a separate vehicle control unit (VCU, Vehicle Control Unit) and transmitted to the torque control unit of the inverter unit.

A drive system for an electric vehicle is also proposed. The drive system comprises a transmission with at least one axle differential of at least one driven axle of the electric vehicle, an electric machine for driving the transmission and an inverter unit for controlling the electric machine. The inverter unit has a torque control unit and a control unit.

The torque control unit detects an actual speed of the electrical machine. The torque control unit calculates a control deviation from the actual speed of the electrical machine and a target speed. The torque control unit has a regulator which calculates a correction torque from the control deviation. The torque control unit calculates a target torque from the correction torque and a default torque. The control unit calculates a target current from the target torque. The control unit controls the electrical machine with the calculated target current.

According to an advantageous embodiment of the invention, the torque control unit has a protection unit. The protection unit calculates the target speed.

According to another advantageous embodiment of the invention, the drive system also includes a separate ESP system (electronic stability program). The ESP system calculates the target speed and transmits the target speed to the torque control unit of the inverter unit.

According to a preferred embodiment of the invention, the drive system also includes a separate vehicle control unit (VCU, Vehicle Control Unit). The vehicle control unit calculates the specified torque and transmits the specified torque to the torque control unit of the inverter unit.

Advantages of the invention

The invention represents a control concept which is a combination of an external speed specification and an internal speed control in the inverter unit includes. This counteracts the approach of long signal propagation times, which are also referred to as latencies, which often causes problems, particularly with a given architecture in the control unit network of ESP, VCU and inverter unit. In previous solutions, when the wheels spin, the drive torque of the at least one electric machine is reduced via the classic TCS control of the ESP. The sole reduction of the drive torque through the TCS function, however, only comes into effect with a delay due to the latencies, so that the drive wheels spinning heavily with a low coefficient of friction can result. In the solution according to the invention, the fast, subordinate speed control directly in the inverter unit means that there are no significant latencies. This largely prevents high speed differences between the wheels and spinning of the drive wheels, in particular during a start-up phase of the electric vehicle. The control concept according to the invention therefore advantageously serves to protect a transmission, in particular an axle differential of a driven axle of an electric vehicle

Figure list

Embodiments of the invention are explained in more detail with reference to the drawings and the following description.

• 1 ein Antriebssystem für ein Elektrofahrzeug gemäß einer ersten Ausführungsform,
• 2 ein Antriebssystem für ein Elektrofahrzeug gemäß einer zweiten Ausführungsform und
• 3 ein Antriebssystem für ein Elektrofahrzeug gemäß einer dritten Ausführungsform.

Show it:

• 1 a drive system for an electric vehicle according to a first embodiment,
• 2 a drive system for an electric vehicle according to a second embodiment and
• 3 a drive system for an electric vehicle according to a third embodiment.

Embodiments of the invention

In the following description of the embodiments of the invention, the same or similar elements are denoted by the same reference numerals, a repeated description of these elements being dispensed with in individual cases. The figures represent the subject matter of the invention only schematically.

1 shows a drive system 100 for an electric vehicle according to a first embodiment. The drive system 100 according to the first embodiment is used in particular in an electric vehicle with a classic ESP-TCS architecture. The drive system 100 according to the first embodiment is only suitable for use in electric vehicles with front-wheel drive or rear-wheel drive.

The drive system 100 comprises a transmission (not shown here) with an axle differential of a driven axle of the electric vehicle. The drive system 100 further comprises an electric machine 54 to drive the gearbox and an inverter unit 30th to control the electrical machine 54 . The inverter unit 30th has a torque control unit 32 and a control unit 52 on. The inverter unit 30th is connected to a battery, not shown here, which provides a DC voltage.

The drive system 100 also includes an ESP system 14th , which is a TCS module 16 (Traction Control System). The ESP system 14th further includes a wheel speed module 18th for acquiring a speed signal 20th a front left wheel, a speed signal 22nd a front right wheel, a speed signal 24 a rear left wheel and a speed signal 26th of a rear right wheel.

The drive system 100 also includes a vehicle control unit 10 . The ESP system 14th determines a TCS target torque 28 and transmits this to the vehicle control unit 10 . The vehicle control unit 10 has a moment module 12 , for example from a position of an accelerator pedal of the electric vehicle and from the TCS setpoint torque 28 a default moment 50 calculated and sent to the torque control unit 32 transmits.

The torque control unit 32 has a protection unit 34 to which of the wheel speed module 18th detected speed signals 20th , 22nd , 24 , 26th are transmitted, and what a target speed 62 the electric machine 54 calculated. In this case, the protection unit calculates 34 the target speed 62 exclusively from speed signals 20th , 22nd , 24 , 26th of wheels of a non-driven axle of the electric vehicle.

The torque control unit 32 records an actual speed 40 the electric machine 54 . The actual speed 40 and the target speed 62 become a subtraction point 36 supplied, from which a system deviation 46 as the difference between the actual speed 40 and the target speed 62 is calculated.

The torque control unit 32 has a regulator 42 to which the control deviation 46 is fed. The protection unit 34 also computes a mode signal 43 and transmits this to the controller 42 . The regulator 42 calculated from the control deviation 46 and the mode signal 43 a correction moment 44 .

The correction moment 44 and the default torque 50 become a summation point 48 supplied from which a target moment 51 as a sum from the correction moment 44 and the default torque 50 is calculated. The control unit 52 calculated from the target moment 51 a target stream 57 and controls the electric machine 54 with the target stream 57 on.

The TCS target torque 28 becomes after coordination with other requirements in the vehicle control unit 10 to the inverter unit 30th Posted. In addition, there are interfaces for recording the speed signals 20th , 22nd , 24 , 26th of the wheel speed module 18th available. The dynamic protective function for the axle differential takes place at least during the latency phase in the inverter unit 30th only based on the actual speed 40 and the speed signals 20th , 22nd , 24 , 26th .

From the speed signals 20th , 22nd , 24 , 26th of the non-driven wheels, the wheel speeds and from this an estimated value for the vehicle speed of the electric vehicle can be derived. In the simplest case, this can be achieved by averaging using the speed signals 20th , 22nd , 24 , 26th of the two non-driven wheels of the electric vehicle. For the two non-driven wheels, it is assumed that they roll almost slip-free when they are driven. The estimated value for the vehicle speed is used as a reference value for forming the target speed 62 . Because the target speed 62 depends primarily on the vehicle speed and does not have high dynamics, has the latency for recording the speed signals 20th , 22nd , 24 , 26th no disturbing influence here.

The target speed 62 is formed as a function of the vehicle speed and is selected in such a way that the difference in speed between the driven wheels, and thus across the axle differential, remains moderate when starting off on a smooth surface on one side. The target speed 62 should also be chosen so that the traction and the side force potential of the driven wheels are maintained on a homogeneous road surface.

As long as a request from the TCS module 16 the inverter unit to reduce the drive torque 30th has not yet reached because of the latency, the inverter unit takes over 30th independently adapting the target torque if necessary 51 for the electric machine 54 . As soon as the mean wheel speed of the driven wheels is greater than the setpoint and the resulting control deviation 46 exceeds a specified threshold, the controller calculates 42 the correction moment 44 , which is then the current external from the vehicle control unit 10 specified default torque 50 is superimposed.

This reduces the excess of drive torque and stabilizes the spinning wheel or both spinning wheels. As a regulator 42 In the simplest case, a P controller or a PDT1 controller can be used. The parameters of the controller 42 are selected if necessary depending on the estimated vehicle speed. The operating point is taken from the vehicle control unit 10 as well as from the ESP system 14th accepted. There is only a quick dynamic correction of the target torque 51 through the controller 42 . By evaluating the wheel speeds, conclusions can be drawn about driving situations such as starting off on a smooth surface on one side and cornering and the parameters of the controller 42 be adapted accordingly.

2 shows a drive system 100 for an electric vehicle according to a second embodiment. The drive system 100 According to the second embodiment, it is used in particular in an electric vehicle with an extended ESP-TCS architecture. The drive system 100 according to the second embodiment is suitable for use in electric vehicles with front-wheel drive or rear-wheel drive or with all-wheel drive.

The drive system 100 comprises a transmission (not shown here) with an axle differential of a driven axle of the electric vehicle. A further axle differential of a second driven axle can also be provided. The drive system 100 further comprises an electric machine 54 to drive the gearbox and an inverter unit 30th to control the electrical machine 54 . The inverter unit 30th has a torque control unit 32 and a control unit 52 on. The inverter unit 30th is connected to a battery, not shown here, which provides a DC voltage.

The drive system 100 also includes an ESP system 14th , which is a TCS module 16 (Traction Control System). The ESP system 14th further includes a wheel speed module 18th for acquiring a speed signal 20th a front left wheel, a speed signal 22nd a front right wheel, a speed signal 24 a rear left wheel and a speed signal 26th of a rear right wheel.

The ESP system 14th also has a TCS setpoint generator 60 on. The TCS setpoint generator 60 calculates a target speed 62 the electric machine 54 that go to the torque control unit 32 is transmitted. The TCS setpoint generator 60 also generates a control mode signal 64 . The torque control unit 32 has a protection unit 34 to which the control mode signal 64 is transmitted.

The drive system 100 also includes a vehicle control unit 10 . The ESP system 14th determines a TCS target torque 28 and transmits this to the vehicle control unit 10 . The vehicle control unit 10 has a moment module 12 , for example from a position of an accelerator pedal of the electric vehicle and from the TCS setpoint torque 28 a default moment 50 calculated and sent to the torque control unit 32 transmits.

The torque control unit 32 records an actual speed 40 the electric machine 54 . The actual speed 40 and the target speed 62 become a subtraction point 36 supplied, from which a system deviation 46 as the difference between the actual speed 40 and the target speed 62 is calculated.

The torque control unit 32 has a regulator 42 to which the control deviation 46 is fed. The protection unit 34 calculated from the control mode signal 64 a mode signal 43 and transmits this to the controller 42 . The regulator 42 calculated from the control deviation 46 and the mode signal 43 a correction moment 44 .

The correction moment 44 and the default torque 50 become a summation point 48 supplied from which a target moment 51 as the sum of the correction torque 44 and the default torque 50 is calculated. The control unit 52 calculated from the target moment 51 a target stream 57 and controls the electric machine 54 with the target stream 57 on.

The default moment 50 becomes after coordination with other requirements in the vehicle control unit 10 to the inverter unit 30th Posted. In addition, there is an associated control mode signal 64 transfer. The speed signals 20th , 22nd , 24 , 26th for the wheel speeds are not required. During the latency phase, the speed control only works on the basis of the current actual speed 40 and the target speed 62 , because the new TCS target torque 28 is not yet available.

The calculation of the target speed 62 takes place in the TCS setpoint generator 60 of the ESP system 14th . For this purpose, the target wheel speed of the TCS module 16 used to determine the associated target speed 62 to determine. The target wheel speed of the TCS module 16 is continuously calculated even with passive TCS function and sent to the inverter unit 30th transmitted. The additionally transmitted control mode signal 64 serves to control the regulator 42 in the inverter unit 30th .

The control deviation 46 is limited asymmetrically, as the controller reduces the drive torque to a greater extent to compensate for the excess torque in the drive train 42 becomes necessary. As long as the request of the TCS module 16 the inverter unit to reduce the drive torque 30th has not yet reached because of the latency, the inverter unit takes over 30th the drive torque of the electrical machine can be adjusted independently if necessary 54 .

As soon as the resulting system deviation 46 exceeds a specified threshold, the controller calculates 42 a correction moment 44 , which is then the current external from the vehicle control unit 10 specified default torque 50 is superimposed. This reduces the excess of drive torque and stabilizes the spinning wheel or both spinning wheels.

As a regulator 42 In the simplest case, a P controller or PDT1 controller can be used. The parameters of the controller 42 are selected depending on the vehicle speed. The vehicle speed does not have to be known exactly. Should the vehicle speed in the inverter unit 30th not be known anyway, this can be obtained from the transmitted setpoint speed 62 to be determined.

The operating point is taken from the vehicle control unit 10 as well as from the ESP system 14th accepted. There is a quick dynamic correction of the target torque 51 through the controller 42 . The driving situations such as starting on a smooth surface on one side as well as cornering and the associated kinematics are already included in the calculation of the transmitted target speed 62 in the ESP system 14th considered.

3 shows a drive system 100 for an electric vehicle according to a third embodiment. The drive system 100 According to the third embodiment, it is used in particular in an electric vehicle with an extended ESP-TCS architecture with additional wheel signal information. The drive system 100 according to the third embodiment is suitable for use in electric vehicles with front-wheel drive or rear-wheel drive or with all-wheel drive.

The drive system 100 comprises a transmission (not shown here) with an axle differential of a driven axle of the electric vehicle. A further axle differential of a second driven axle can also be provided. The drive system 100 further comprises an electric machine 54 to drive the gearbox and an inverter unit 30th to control the electrical machine 54 . The inverter unit 30th has a torque control unit 32 and a control unit 52 on. The inverter unit 30th is connected to a battery, not shown here, which provides a DC voltage.

The drive system 100 also includes an ESP system 14th , which is a TCS module 16 (Traction Control System). The ESP system 14th further includes a wheel speed module 18th for acquiring a speed signal 20th a front left wheel, a speed signal 22nd a front right wheel, a speed signal 24 a rear left wheel and a speed signal 26th of a rear right wheel.

The ESP system 14th also has a TCS setpoint generator 60 on. The TCS setpoint generator 60 calculates a target speed 62 the electric machine 54 that go to the torque control unit 32 is transmitted. The TCS setpoint generator 60 also generates a control mode signal 64 . The torque control unit 32 has a protection unit 34 to which the control mode signal 64 is transmitted. Also from the wheel speed module 18th detected speed signals 20th , 22nd , 24 , 26th become a protective unit 34 transfer.

The drive system 100 also includes a vehicle control unit 10 . The ESP system 14th determines a TCS target torque 28 and transmits this to the vehicle control unit 10 . The vehicle control unit 10 has a moment module 12 , for example from a position of an accelerator pedal of the electric vehicle and from the TCS setpoint torque 28 a default moment 50 calculated and sent to the torque control unit 32 transmits.

The torque control unit 32 records an actual speed 40 the electric machine 54 . The actual speed 40 and the target speed 62 become a subtraction point 36 supplied, from which a system deviation 46 as the difference between the actual speed 40 and the target speed 62 is calculated.

The torque control unit 32 has a regulator 42 to which the control deviation 46 is fed. The protection unit 34 calculated from the control mode signal 64 a mode signal 43 and transmits this to the controller 42 . The regulator 42 calculated from the control deviation 46 and the mode signal 43 a correction moment 44 .

The correction moment 44 and the default torque 50 become a summation point 48 supplied from which a target moment 51 as the sum of the correction torque 44 and the default torque 50 is calculated. The control unit 52 calculated from the target moment 51 a target stream 57 and controls the electric machine 54 with the target stream 57 on.

The default moment 50 becomes after coordination with other requirements in the vehicle control unit 10 to the inverter unit 30th Posted. In addition, there is an associated control mode signal 64 transfer. In addition, the speed signals 20th , 22nd , 24 , 26th for the wheel speeds.

During the latency phase, the speed control only works on the basis of the current actual speed 40 and the target speed 62 , because the new TCS target torque 28 is not yet available. The speed signals 20th , 22nd , 24 , 26th are used to differentiate the individual driving situations even more precisely. With the help of the difference in the wheel speeds on the driven axle, the situation “starting on a smooth surface on one side” can be better differentiated from the situation “starting on a homogeneous coefficient of friction” with symmetrically spinning wheels.

The calculation of the target speed 62 takes place in the TCS setpoint generator 60 of the ESP system 14th . For this purpose, the target wheel speed of the TCS module 16 used to determine the associated target speed 62 to determine. The target wheel speed of the TCS module 16 is continuously calculated even with passive TCS function and sent to the inverter unit 30th transmitted. The additionally transmitted control mode signal 64 serves to control the regulator 42 in the inverter unit 30th .

As a regulator 42 In the simplest case, a P controller or PDT1 controller can be used. The parameters of the controller 42 are selected depending on the vehicle speed. The vehicle speed does not have to be known exactly. Should the vehicle speed in the inverter unit 30th not be known anyway, this can be obtained from the transmitted setpoint speed 62 to be determined.

The invention is not restricted to the exemplary embodiments described here and the aspects emphasized therein. Rather, within the range specified by the claims, a large number of modifications are possible that are within the scope of expert knowledge.

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102011088729 A1 [0002]
• DE 102016203113 A1 [0003]
• EP 2810132 B1 [0004]

Claims (11)

A method for operating a drive system (100) of an electric vehicle, comprising a transmission with at least one axle differential of at least one driven axle of the electric vehicle, an electric machine (54) for driving the transmission and an inverter unit (30) for controlling the electric machine (54), which has a torque control unit (32) and a control unit (52), wherein an actual speed (40) of the electrical machine (54) is detected by the torque control unit (32); the torque control unit (32) calculates a control deviation (46) from the actual speed (40) of the electrical machine (54) and a setpoint speed (62); A regulator (42) of the torque control unit (32) calculates a correction torque (44) from the control deviation (46); a target torque (51) is calculated by the torque control unit (32) from the correction torque (44) and a preset torque (50); a target current (57) is calculated by the control unit (52) from the target torque (51); and the electrical machine (54) is controlled by the control unit (52) with the target current (57). Procedure according to Claim 1 , wherein the torque control unit (32) has a protection unit (34), from which the setpoint speed (62) is calculated. Procedure according to Claim 2 , wherein the target speed (62) is calculated by the protection unit (34) from speed signals (20, 22, 24, 26) from all wheels of the electric vehicle. Procedure according to Claim 2 , wherein the target speed (62) is calculated by the protection unit (34) exclusively from speed signals (20, 22, 24, 26) from wheels of a non-driven axle of the electric vehicle. Procedure according to Claim 1 wherein the setpoint speed (62) is calculated by an ESP system (14) and transmitted to the torque control unit (32). Method according to one of the preceding claims, wherein a control mode signal 64 is generated by an ESP system (14) and transmitted to the torque control unit (32). Method according to one of the preceding claims, wherein the specified torque (50) is calculated by a vehicle control device (10) and transmitted to the torque control unit (32). A drive system (100) for an electric vehicle, comprising a transmission with at least one axle differential of at least one driven axle of the electric vehicle, an electric machine (54) for driving the transmission and an inverter unit (30) for controlling the electric machine (54), which has a torque control unit (32) and a control unit (52), wherein the torque control unit (32) detects an actual speed (40) of the electrical machine (54); the torque control unit (32) calculates a control deviation (46) from the actual speed (40) of the electrical machine (54) and a target speed (62); the torque control unit (32) has a regulator (42) which calculates a correction torque (44) from the control deviation (46); the torque control unit (32) calculates a target torque (51) from the correction torque (44) and a preset torque (50); the control unit (52) calculates a target current (57) from the target torque (51); and the control unit (52) controls the electrical machine (54) with the target current (57). Drive system (100) Claim 8 , wherein the torque control unit (32) has a protection unit (34) which calculates the target speed (62). Drive system (100) according to one of the Claims 8 to 9 , further comprising an ESP system (14) which calculates the setpoint speed (62) and transmits it to the torque control unit (32). Drive system (100) according to one of the Claims 8 to 10 , further comprising a vehicle control device (10), which calculates the specified torque (50) and transmits it to the torque control unit (32).

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