Control device and method for verifying the calibration of an electric machine

Abstract

A control device (1) is provided for checking the calibration of an electric machine (10) which is installed as a drive machine in a motor vehicle (70), characterized in that the control device (1) is designed to brake the motor vehicle (70) (S1), to apply a target torque to a drive train (50) of the motor vehicle (70) by means of the electric machine (10) (S2) and to verify the target torque (S3).

Description

[0001] The present disclosure relates to a control device for verifying the calibration of an electric machine installed as a drive motor in a motor vehicle, a motor vehicle comprising the control device, and / or a method for verifying the calibration of an electric machine installed as a drive motor in a motor vehicle. Additionally, or alternatively, a computer program is provided that includes instructions which, when executed by a computer, cause the computer to execute the method, at least partially. Additionally, or alternatively, a computer-readable medium is provided that includes instructions which, when executed by a computer, cause the computer to execute the method, at least partially.

[0002] Electrically powered vehicles use electric machines as drive motors. Each of these machines generates a drive force or torque when supplied with an electric current, which is then transmitted via the drivetrain to the vehicle's wheels, or at least one of the vehicle's wheels. The electric machine can, for example, be part of an individual wheel drive or a wheel-selective drive, allowing for individual drive torque to be applied to each of the vehicle's wheels.

[0003] Electric machines have limited accuracy with regard to the set (torque) value; however, especially with wheel-selective drives, the highest possible torque accuracy should be achieved, as too great a deviation of the torque from the respective target torque negatively affects the driving dynamics (too much).

[0004] WO 2021 / 104752 A1 describes a method for calibrating an offset angle of a field-oriented control of an electric machine between an angle signal of a position sensor and the direction of the rotor flux, comprising the steps: periodically varying a current phasor along a line of constant torque, determining a speed signal of the position sensor of the electric machine and calibrating the offset angle as a function of the determined speed signal.

[0005] DE 10 2019 100 324 A1 describes a device for calibrating two electric motors arranged on one axle in two-axle motor vehicles with at least one electronic control unit, wherein the control unit is designed such that the following steps are performed while the vehicle is in motion. In a first step, it is checked whether predefined conditions for switching from torque control to speed control are met. If this is the case, the system switches to speed control for a predefined period. During the predefined period, in a second step, the target torques of the two electric motors are recorded and stored, and a difference is calculated between the recorded target torques of the two electric motors, whereby a torque-dependent characteristic map with correction values ​​based on this difference is created.After deactivating the speed control, the target torques are corrected by the correction values ​​during torque control.

[0006] DE 10 2010 027 222 A1 describes a device for testing and calibrating power screwdrivers to a predetermined tightening torque, comprising a coupling for the output of the power screwdriver, which is connected by means of a shaft to a controllable electromagnetic brake, and a sensor unit for detecting mechanical quantities that occur according to the torque transmitted between the coupling and the brake. The moment of inertia of the device is reduced by providing a rotor for the electromagnetic brake that has the form of a hollow cylinder.

[0007] Against the background of this prior art, the purpose of the present disclosure is to specify a device and / or a method, each of which is suitable to enrich the prior art.

[0008] The problem is solved by the features of the independent claims. The dependent and subordinate claims each contain optional further developments of the disclosure.

[0009] The task is then solved by a control device for checking a calibration, e.g. torque calibration, (or for torque plausibility check) of an electric machine that is installed as a drive machine in a motor vehicle.

[0010] The control device is designed to brake the motor vehicle (e.g., when the motor vehicle is stationary).

[0011] The control device is designed to apply a target torque to the vehicle's drivetrain via the electric motor. This target torque can be a target torque and / or a target drive torque.

[0012] The control device is designed to validate the target torque.

[0013] Plausibility checks can be understood as verifying the target torque against (at least) one measured variable to determine whether the target torque is plausible, or whether the target torque and the (at least) one measured variable are plausible in relation to each other. The measured variable can be usefully dependent on the target torque, so that, for example, an actual torque (or actual torque and / or actual drive torque) can be determined from the measured variable. Plausibility checks can include a comparison of the target torque and the actual torque (or a value of the target torque and a value of the actual torque), whereby the target torque can be considered plausible if the deviation between the value of the target torque and the value of the actual torque does not exceed a predefined maximum deviation.

[0014] The control device can be designed for electronic data processing, which may include, for example, one or more microprocessors and data storage devices. Software for data processing and, for example, for validating the target torque can be run on the control device.

[0015] The control device described above offers a number of advantages. Among other things, it provides improved technology that allows for verification of a calibration, e.g., torque calibration, of the electric machine (and, if necessary, a (re-)calibration) in the installed state and during operation of the vehicle, and not only during production, e.g., during an end-of-line (EOL) test or a conformity of production (COP) check.

[0016] This allows the calibration of the electric motor to be checked regularly during the vehicle's operating life, for example, in order to advantageously detect changes in torque accuracy and, if necessary, correct any degradation through (re)calibration. Similarly, negative influences on the vehicle's driving dynamics can be detected in a timely manner and, if necessary, eliminated.

[0017] Possible further developments of the control device described above are explained in detail below.

[0018] The control device can be designed to verify the plausibility of the target torque in order to obtain a measured value that depends on the target torque and has been determined by a measuring device on or in the drive train and / or on or in the electric machine, and to verify the plausibility of the target torque on the basis of the measured value.

[0019] The measured variable can be a rotor position and / or deformation (or tension) of a rotor of the electric machine, and the measuring device can be a rotor position sensor on the rotor.

[0020] The measured quantity can be a force and / or a moment (e.g. rotational and / or drive torque) in or on a component of the drive train.

[0021] The component can be a decoupling unit of the drive train and the measuring device can be a sensor device and / or load cell in or on the decoupling unit.

[0022] The control device can be designed to calibrate the electric machine depending on the plausible target torque. The calibration can include calibrating the electric machine and / or the target torque if the plausibility check of the target torque yields an implausible target torque, until a further plausibility check of the target torque yields a plausible target torque.

[0023] The control device can be designed to lock the motor vehicle in order to actuate a parking lock and / or at least one wheel brake of the motor vehicle, to initiate braking and / or locking the motor vehicle.

[0024] Applying the target torque to the drivetrain can include the possibility of applying, or applying, the target torque to an axle, e.g., a longitudinal axis and / or drive axle, and / or a vehicle wheel of the motor vehicle (or the drivetrain of the motor vehicle).

[0025] The above can be summarized in other words and in a possible more concrete elaboration of the revelation as described below, whereby the following description is to be interpreted as not being restrictive for the revelation.

[0026] The vehicle can be, or become, braked while stationary and, via the drive motor (i.e., the electric motor), apply a torque to the axle (e.g., the longitudinal axis and / or drive axle of the drivetrain) or, in the case of wheel-selective drives, to the vehicle wheel. The applied torque can then be measured and validated via a rotor position sensor and / or a sensor in the drivetrain.

[0027] For example, a sensor can be housed in a decoupling unit, e.g., a load cell. For (standard) drives without a decoupling unit, the rotor position sensor can be used, for example, to measure gearbox preload. A wheel brake or the vehicle's parking brake can be used as the brake.

[0028] Furthermore, a motor vehicle (e.g., electrically powered) is provided, comprising the control device described above and the electric machine installed as a drive machine in the motor vehicle.

[0029] The electric machine can be a wheel-selective drive machine of the motor vehicle.

[0030] The motor vehicle can be a passenger car, in particular an automobile, or a commercial vehicle, such as a truck.

[0031] The above description with reference to the control device also applies analogously to the motor vehicle and vice versa.

[0032] Furthermore, a method for verifying the calibration, e.g., torque calibration (or torque plausibility check), of an electric machine installed as a drive motor in a motor vehicle is provided. This method can be controlled or executed, for example, by the control device described above.

[0033] The procedure involves applying the brakes to the vehicle.

[0034] The process involves applying a target torque to the motor vehicle's drivetrain using the electric machine.

[0035] The procedure includes a plausibility check of the target moment.

[0036] The (control) procedure can be a computer-implemented procedure, i.e., one, several or all steps of the procedure can be at least partially carried out by a computer or a data processing device, optionally the control device.

[0037] What has been described above with reference to the control device and the motor vehicle also applies analogously to the procedure and vice versa.

[0038] Furthermore, a computer program comprising commands that, when executed by a computer, cause it to at least partially execute the procedure described above is provided.

[0039] The program code of a computer program can be in any type of code, especially code suitable for controlling motor vehicles.

[0040] What has been described above with reference to the control device, the motor vehicle and the procedure also applies analogously to the computer program and vice versa.

[0041] Furthermore, a computer-readable medium, in particular a computer-readable storage medium, is provided. The computer-readable medium comprises instructions which, when executed by a computer, cause it to at least partially execute the procedure described above.

[0042] This means that a computer-readable medium can be provided that contains a computer program as defined above. The computer-readable medium can be any digital data storage device, such as a USB flash drive, a hard drive, a CD-ROM, an SD card, or an SSD card (or SSD drive / SSD hard drive).

[0043] The computer program does not necessarily have to be stored on such a computer-readable storage medium in order to be made available to the motor vehicle, but can also be obtained via the Internet or other external sources.

[0044] The above description relating to the procedure, the control device, the computer program and the motor vehicle also applies analogously to the computer-readable medium and vice versa.

[0045] The following is an optional embodiment with reference to Fig. 1 and Fig. 2 described. Fig. Figure 1 schematically shows a section of a motor vehicle according to the disclosure with a control device for checking a calibration of an electric machine, and Fig. Figure 2 schematically shows a flowchart of a procedure according to the disclosure for verifying a calibration of the electrical machine.

[0046] In Fig. Figure 1 is merely a schematic representation of a section of the motor vehicle 70, comprising a control device 1 and an electric machine 10. The electric machine 10 is designed as part of a drive train 50 of the motor vehicle 70 or is installed in the motor vehicle 70 as, for example, a wheel-selective drive machine.

[0047] The electric machine 10 can be configured to apply a target torque to the drive train 50, i.e., to transmit a torque via a rotor 12 of the electric machine 10 and other components 20 of the drive train 50 to a drive shaft 30 and finally to a vehicle wheel 40. In a wheel-selective drive, the electric machine 10 can be assigned to exactly one vehicle wheel 40; however, it is also conceivable that the electric machine 10 is configured to drive several drive shafts and / or several vehicle wheels.

[0048] The other components 20 of the drive train may include a gearbox, a driveshaft, a differential and / or a decoupling unit.

[0049] The vehicle wheel 40 has a wheel brake 42 for braking the motor vehicle 10.

[0050] Furthermore, in this embodiment, the motor vehicle 70 has a rotor position sensor 60 which is arranged on the rotor 12 of the electric machine 10.

[0051] The control device 1 is connected via signal transmission to the electric machine 10, the wheel brake 42, and the rotor position sensor 60. It is also conceivable that the control device 1 could be connected via signal transmission to the wheel brakes of other vehicle wheels and / or to other or additional measuring devices on or in the drive train 50.

[0052] To verify a calibration, e.g. torque calibration, of the electric machine 10, the control device 1 is designed to perform the following also with reference to Fig. 2 procedures described in detail 100 to be carried out.

[0053] In a first process step S1, the motor vehicle 70 is braked, e.g. by means of the wheel brake 42.

[0054] In a second process step S2, the drive train 50 of the motor vehicle 70 is subjected to a target torque by means of the electric machine 10.

[0055] In a third process step S3, the target torque is made plausible, e.g. by means of a measured quantity that depends on the target torque and has been determined by a measuring device on or in the drive train 50 and / or on or in the electric machine 10.

[0056] The measured variable can be, for example, a rotor position and / or deformation of the rotor 12 of the electric machine 10, which has been determined by the rotor position sensor 60 on the rotor 12 while the motor vehicle 70 is braked.

[0057] It is also conceivable that the measured quantity is a force and / or a torque that has been detected in or on a component of the drive train 50. For example, a force and / or torque on or in a decoupling unit of the drive train 5 can be determined by means of a sensor device and / or load cell.

[0058] In a fourth process step S4, the electric machine 10 can be calibrated depending on the plausible target torque. Reference symbol list 1 Control device 10 electric machine 12 Rotor of the electric machine 20 components of the drivetrain, e.g. transmission 30 Drive shaft 40 vehicle wheel 42 Wheel brake 50 Powertrain 60 Rotor position sensor 70 motor vehicles 100 procedures S1-S4 process steps QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] WO 2021 / 104752 A1

[0004] DE 10 2019 100 324 A1

[0005] DE 10 2010 027 222 A1

[0006]

Claims

[1] Control device (1) for checking a calibration of an electrical machine (10) which is installed as a drive machine in a motor vehicle (70), characterized by that the control device (1) is designed to: - to brake the motor vehicle (70) (S1); - to apply a desired torque (S2) to a drive train (50) of the motor vehicle (70) by means of the electric machine (10); and - to verify the target torque (S3). [2] Control device (1) according to claim 1, characterized by that the control device (1) is designed to check the plausibility (S3) of the target torque in order to: - to obtain a measured variable which depends on the target torque and has been determined by a measuring device (60) on or in the drive train (50) and / or on or in the electric machine (10); and - to verify the plausibility of the target torque based on the measured value obtained. [3] Control device (1) according to claim 2, characterized by that the measured variable is a rotor position and / or deformation of a rotor (12) of the electrical machine (10) and the measuring device is a rotor position sensor (60) on the rotor (12). [4] Control device (1) according to claim 2 or 3, characterized by that the measured variable is a force and / or a moment in or on a component of the drive train (50). [5] Control device (1) according to claim 4, characterized by that the component is a decoupling unit of the drive train (50) and the measuring device is a sensor device and / or load cell in or on the decoupling unit. [6] Control device (1) according to one of claims 1 to 5, characterized by that the control device (1) is designed to: - to calibrate the electric machine (10) depending on the plausibility-checked target torque (S4). [7] Motor vehicle (70), characterized bythat the motor vehicle (70) comprises: - the control device (1) according to one of claims 1 to 6; and - the electric machine (10) which is installed as a drive machine in the motor vehicle (70). [8] Motor vehicle (70) according to claim 7, characterized by that the electric machine (10) is a wheel-selective drive machine of the motor vehicle (70). [9] Method (100) for checking a calibration of an electrical machine (10) installed as a drive machine in a motor vehicle (70), characterized by that the method (100) comprises: - hard braking (S1) of the motor vehicle (70); - applying (S2) a drive train (50) of the motor vehicle (70) with a desired torque by means of the electric machine (10); and - Plausibility check (S3) of the target torque. [10] Computer program and / or computer-readable medium, characterized bythat the computer program comprises instructions and / or computer-readable medium which, when the program is executed by a computer, cause the computer to carry out the method (100) according to claim 9.

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