A method for generating at least one control signal for controlling an axial flux motor of a motor vehicle, a corresponding computer program product

Abstract

The present invention relates to motor vehicles such as electric vehicles and involves generating at least one control signal 18 for controlling an axial flux motor (14, Fig. 1) of the vehicle by an e

Description

[0001] The present invention relates to the field of automobiles. More specifically, the present invention relates to a method for rotor temperature compensation for generating at least one control signal for controlling an axial flux motor of a motor vehicle by an electronic computing device. Furthermore, the present invention relates to a corresponding computer program product, a corresponding non-transitory computer-readable storage medium, as well as to a corresponding electronic computing device. BACKGROUND INFORMATION

[0002] Axial flux motors may not have rotor coolants and / or cooling systems. As a result, the rotor temperature varies from minus 40 degrees Celsius to 120 degrees Celsius depending on environmental and operating conditions. The large variation of rotor temperature has a large impact on the torque accuracy, for example every 10 degrees Celsius, the rotor temperature increase can lead to around 1% torque drop. The rotor temperature variation also changes the optimal operating curves which impact the efficiency.

[0003] When the rotor temperature changes, all operating curves shift, for example MTPA, MTPV, equal torque line, equal flux line and furthermore, which impacts the torque accuracy and efficiency. SUMMARY OF THE INVENTION

[0004] It is an object of the present invention to provide a method, a corresponding computer program product, a corresponding non-transitory computer-readable storage medium, as well as a corresponding electronic computing device, by which the torque accuracy of an axial flux motor is improved.

[0005] This object is solved by a method, a corresponding computer program product, a corresponding non-transitory computer-readable storage medium, as well as a corresponding electronic computing device according to the independent claims. Advantageous embodiments are presented in the dependent claims.

[0006] One aspect of the present invention relates to a method for rotor temperature compensation for generating at least one control signal for controlling an axial flux motor of a motor vehicle by an electronic computing device. At least two control models for controlling the axial flux motor are provided by the electronic computing device. A rotor temperature of the axial flux motor is received by the electronic computing device. A current control model is selected depending on the received rotor temperature by the electronic computing device and the control signal is generated by using the selected control model by the electronic computing device.

[0007] Therefore, in particular with the knowledge of the changing accuracy at least two sets of control tables calibrated offline based on at least two different motor temperatures are provided, wherein a control structure with at least two sets of control tables is provided to interpolate the final control set points for any given temperature within the temperature range.

[0008] In particular, in order to keep the existing control as much as possible, at least two sets of motor data are used to generate two sets of control tables. This may increase the table dimensions to include the temperature as a new input and allow the interpretation of the whole temperature range. In particular, the proposal may rely on the accuracy of a motor simulation data for production.

[0009] The method provides an accurate rotor temperature compensation method based on multiple sets of machine characterization data and data interpolation, it is effective for both torque accuracy and efficiency.

[0010] According to an embodiment, at least four control models for at least four different temperatures are provided.

[0011] In another embodiment, an Id / lq current commands calculation model controlling of the axial flux motor is provided.

[0012] In another embodiment, the at least two control models are generated by a simulation of the axial flux motor.

[0013] In another embodiment, a numeric data processing method such as least-square-curve fitting is performed for controlling the axial flux motor.

[0014] In another embodiment, a rotor temperature of a rotor of the axial flux motor is captured and transmitted to the electronic computing device.

[0015] In particular, the method is a computer-implemented method. Therefore, another aspect of the invention relates to a computer program product comprising program code means for performing a method according to the preceding aspect.

[0016] Furthermore, the present invention relates to a non-transitory computer-readable storage medium comprising at least the computer program product according to the preceding aspect.

[0017] Furthermore, the present invention relates to an electronic computing device for generating at least one control signal for controlling an axial flux motor of a motor vehicle, wherein the electronic computing device is configured for performing a method according to the preceding aspect. In particular, the method is performed by the electronic computing device.

[0018] Furthermore, the present invention relates to an axial flux motor comprising at least the electronic computing device according to the preceding aspect. In some embodiments, the present invention may be implemented for permanent magnet motors.

[0019] Furthermore, the present invention relates to a motor vehicle comprising at least the axial flux motor according to the preceding aspect. In particular, the motor vehicle may be configured as an at least in part electrically operated motor vehicle or a fully electrically operated motor vehicle.

[0020] Advantageous embodiments of the method are to be regarded as advantageous embodiments of the computer program product, the non-transitory computer-readable storage medium, the electronic computing device, the axial flux motor, as well as the motor vehicle. Therefore, the electronic computing device, the axial flux motor, as well as the motor vehicle comprises means for performing the method.

[0021] A computing unit / electronic computing device may in particular be understood as a data processing device, which comprises processing circuitry. The computing unit can therefore in particular process data to perform computing operations. This may also include operations to perform indexed accesses to a data structure, for example a look-up table, LUT.

[0022] In particular, the computing unit may include one or more computers, one or more microcontrollers, and / or one or more integrated circuits, for example, one or more application-specific integrated circuits, ASIC, one or more field-programmable gate arrays, FPGA, and / or one or more systems on a chip, SoC. The computing unit may also include one or more processors, for example one or more microprocessors, one or more central processing units, CPU, one or more graphics processing units, GPU, and / or one or more signal processors, in particular one or more digital signal processors, DSP. The computing unit may also include a physical or a virtual cluster of computers or other of said units.

[0023] In various embodiments, the computing unit includes one or more hardware and / or software interfaces and / or one or more memory units.

[0024] A memory unit may be implemented as a volatile data memory, for example a dynamic random access memory, DRAM, or a static random access memory, SRAM, or as a non-volatile data memory, for example a read-only memory, ROM, a programmable readonly memory, PROM, an erasable programmable read-only memory, EPROM, an electrically erasable programmable read-only memory, EEPROM, a flash memory or flash EEPROM, a ferroelectric random access memory, FRAM, a magnetoresistive random access memory, MRAM, or a phase-change random access memory, PCRAM.

[0025] Further advantages, features, and details of the present invention derive from the following description of preferred embodiments as well as from the drawings. The features and feature combinations previously mentioned in the description as well as the features and feature combinations mentioned in the following description of the figures and / or shown in the figures alone can be employed not only in the respectively indicated combination but also in any other combination or taken alone without leaving the scope of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The novel features and characteristic of the disclosure are set forth in the appended claims. The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate exemplary embodiments and together with the description, serve to explain the disclosed principles. The same numbers are used throughout the figures to reference like features and components. Some embodiments of system and / or methods in accordance with embodiments of the present subject matter are now described below, by way of example only, and with reference to the accompanying figures.

[0027] The drawings show in:

[0028] Fig. 1 a schematic side view according to the embodiment of a motor vehicle comprising an embodiment of an axial flux motor comprising an embodiment of an electronic computing device; and

[0029] Fig. 2 a schematic block diagram according to an embodiment of the electronic computing device.

[0030] In the figures the same elements or elements having the same function are indicated by the same reference signs. DETAILED DESCRIPTION

[0031] In the present document, the word "exemplary" is used herein to mean "serving as an example, instance, or illustration". Any embodiment or implementation of the present subject matter described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.

[0032] While the present disclosure is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawing and will be described in detail below. It should be understood, however, that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternatives falling within the scope of the disclosure.

[0033] The terms “comprises”, “comprising”, or any other variations thereof, are intended to cover a non-exclusive inclusion so that a setup, device or method that comprises a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such setup or device or method. In other words, one or more elements in a system or apparatus preceded by “comprises” or “comprise” does not or do not, without more constraints, preclude the existence of other elements or additional elements in the system or method.

[0034] In the following detailed description of the embodiment of the present disclosure, reference is made to the accompanying drawing that forms part hereof, and in which is shown by way of illustration a specific embodiment in which the disclosure may be practiced. This embodiment is described in sufficient detail to enable those skilled in the art to practice the disclosure, and it is to be understood that other embodiments may be utilized and that changes may be made without departing from the scope of the present disclosure. The following description is, therefore, not to be taken in a limiting sense.

[0035] Fig. 1 shows a schematic side view according to an embodiment of a motor vehicle 10. The motor vehicle 10 is in particular at least in part electrically operated or fully electrically operated. The motor vehicle 10 therefore comprises, for example, one electric energy storage device 12.

[0036] Furthermore, the present embodiment of the motor vehicle 10 comprises at least one axial flux motor 14, as well as one electronic computing device 16.

[0037] Fig. 2 shows a schematic block diagram according to an embodiment of the electronic computing device 16. According to the shown embodiment, the electronic computing device 16 is configured for generating at least one control signal 18 for controlling the axial flux motor 14 of the motor vehicle 10. At least two control models 20, 22, 24, 26 for controlling the axial flux motor 14 are provided by the electronic computing device 16. A rotor temperature 28 of the axial flux motor 14 is received by the electronic computing device 16. The current control model 20, 22, 24, 26 is selected depending on the received rotor temperature 28 by the electronic computing device 16 and the control signal 18 is generated by using the selected control model 20, 22, 24, 26 by the electronic computing device 16.

[0038] In particular, at least four control model 20, 22, 24, 26 for four different temperatures are provided.

[0039] Furthermore, an Id / lq current commands calculation model controlling of the axial flux motor 14 is provided.

[0040] In another embodiment, the at least two control models 20, 22, 24, 26 are generated by simulation and experiment of the axial flux motor 14.

[0041] In another embodiment, a numeric data processing method such as least-square-curve fitting 30 is performed for controlling the axial flux motor 14.

[0042] In another embodiment, the rotor temperature of a rotor of the axial flux motor 14 is captured and transmitted to the electronic computing device 16.

[0043] In particular, Fig. 2 shows that, for example, a commanded temperature signal 32, a speed 34, as well as a voltage 36 of the electric storage device 12 is provided for the electronic computing device 16. A first control model 20, for example, for a temperature of negative 25 degrees Celsius, a second control model 22 for a temperature of 50 degrees Celsius, a third control model 24 for a temperature of 110 degrees Celsius, and a fourth control model 26 for a reference temperature of 80 degrees Celsius are provided. A first output signal 38 for the first control model 20, a second output signal 46 for the second control model 22, a third output signal 48 for the third control model 24, and a fourth output signal 50 for the fourth control model 26 may comprise a current Id, a current lq, and a maximum temperature for each model. For example, the third control model 20 may comprise the output signal 48 as ld for 110 degrees Celsius, lq for 110 degrees Celsius, and the maximum available torque Tmax of 110 degrees Celsius.

[0044] The control signal 18 may comprise further at least three control signals, in particular the ld control signal 40, the lq control signal 42, and the maximum available torque Tmax signal 44, wherein the control signals 18 are provided for the axial flux motor 14. Therefore, the present invention provides a rotor temperature compensation proposal in order to maintain the existing control structure as much as possible. In particular, four sets of motor data to generate four sets of control tables are provided. The Id / lq current commands calculation model table dimension therefore is increased to include the temperature as a new input and allow interpretation of the whole temperature range. This present invention also relies on the accuracy of a motor simulation data and experiment data for production. Reference Signs 10 motor vehicle 12 electrical energy storage device 14 axial flux motor 16 electronic computing device 18 control signal 20 first control model 22 second control model 24 third control model 26 fourth control model 28 rotor temperature 30 least-square-curve fitting 32 commanded temperature 34 speed 36 voltage 38 first output signals 40 Id 42 iq 44 Maximum Available Torque (Tmax) 46 second output signals 48 third output signals 50 fourth output signals

Claims

1. A method for generating at least one control signal (18) for controlling an axial flux motor (14) of a motor vehicle (10) by an electronic computing device (16), comprising the steps of:- providing at least two control models (20, 22, 24, 26) for controlling the axial flux motor (14) by the electronic computing device (16);- receiving a rotor temperature (28) of the axial flux motor (14) by the electronic computing device (16);- selecting a current control model (20, 22, 24, 26) depending on the received rotor temperature (28) by the electronic computing device (16); and- generating the control signal (18) by using the selected control model (20, 22, 24, 26) by the electronic computing device (16).

2. The method according to claim 1, characterized in that at least two control models (e.g four control models (20, 22, 24, 26) can be used) for at least two different temperatures (e.g. four different temperatures can be used) are provided.

3. The method according to claim 1 or 2, characterized in that an Id / lq current commands calculation model controlling of the axial flux motor (14) is provided.

4. The method according to any one of claims 1 to 3, characterized in that the at least two control models (20, 22, 24, 26) are generated by a simulation and experiment of the axial flux motor (14).

5. The method according to any one of claims 1 to 4, characterized in that a least-square-curve fitting (30) is performed for controlling the axial flux motor (14).

6. The method according to any one of claims 1 to 5, characterized in that a rotor temperature of a rotor of the axial flux motor (14) is captured and transmitted to the electronic computing device (16).

7. A computer program product comprising program code means for performing a method according to any one of claims 1 to 6.

8. A non-transitory computer-readable storage medium comprising the computer program product according to claim 7.

9. An electronic computing device (16) for generating at least one control signal (18) for controlling an axial flux motor (14) of a motor vehicle (10), wherein the electronic computing device (16) is configured for performing a method according to any one of claims 1 to 6.12

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