AT526204B1 - Method and system for optimizing system efficiency and reducing audible and/or noticeable vibrations of an electric drive system of a motor vehicle - Google Patents

Abstract

The present invention relates to a computer-implemented method (30) and a system (20) for optimizing the efficiency of an electric drive system (11) of a motor vehicle (10) and for reducing the audible and/or noticeable vibrations of the electric drive system (11) of the motor vehicle (10) by outputting an optimized operating map (5) for the electric motor (12) of the electric drive system (11).

Description

Description

METHOD AND SYSTEM FOR OPTIMIZING SYSTEM EFFICIENCY AND FOR REDUCING THE AUDIBLE AND/OR NOTICEABLE VIBRATIONS OF AN ELECTRICAL DRIVE SYSTEM OF A MOTOR VEHICLE

The present invention relates to a method and a system for optimizing the efficiency of an electric drive system of a motor vehicle and for reducing the audible and/or noticeable vibrations of the electric drive system by outputting an optimized operating map for an electric motor of the electric drive system and a computer program product.

[0002] Improving driving comfort is one of the major issues for the future of mobility, especially electromobility. Part of this is the reduction of audible and/or noticeable vibrations (“Noise Vibration Harshness”, or NVH for short) during operation of the motor vehicle. In addition, optimizing the efficiency of vehicles, especially electrically powered vehicles, is also an important issue in order to provide long ranges and keep consumption costs low.

Various approaches are known from the prior art to achieve the goal of NVH reduction, for example by adapting the geometry of the motor vehicle or adding damping elements in the motor vehicle. This is for example from DENG, W. et al. “Electromagnetic Vibration and Noise of the Permanent-Magnet Synchronous Motors for Electric Vehicles: An OverView,” IEEE Transactions on Transportation Electrification, March 1, 2019 (03/01/2019), Vol.5, No. 1, pages 59-70, XP011715844. In addition, the documents DE 19827133 A1 and ATTAIANESE, C. et al. “Maximum Torque Per Watt (MTPW) field-oriented control of “induction motor” Electrical Engineering [online], December 1, 2021 (December 1, 2021). Vol. 103, No. 6, pages 2611-2623, XP037622672, which deal with NVH reduction and efficiency optimization using MTPW (Maximum Torque per Watt).

[0004] However, the known approaches are associated with disadvantages, such as higher costs, higher weight, etc. In addition, there are limits to the known approaches. In the prior art, it is hardly possible or only possible with difficulty to reduce the audible and/or noticeable vibrations of components of the electric drive system of a motor vehicle.

It is the object of the present invention to at least partially eliminate the disadvantages described above. In particular, it is the object of the present invention to increase the driving comfort of a motor vehicle with an electric drive system in a cost-effective and simple manner by reducing audible and/or noticeable vibrations, while at the same time enabling high efficiency and range of the vehicle.

The above object is achieved by a method with the features of claim 1, a system with the features of claim 13 and a computer program product with the features of claim 14. Further features and details of the invention emerge from the subclaims and the description and the drawings. Features and details that are described in connection with the method according to the invention naturally also apply in connection with the system according to the invention and the computer program product according to the invention and vice versa, so that reference is or can always be made to each other with regard to the disclosure of the individual aspects of the invention .

According to the invention, a method is provided for optimizing the efficiency of an electric drive system of a motor vehicle and for reducing the audible and/or noticeable vibrations of the electric drive system of the motor vehicle by outputting an optimized operating map for an electric motor of the electric drive system. The process has the following steps:

(a) providing an operating map of the electric motor that is pre-optimized for efficiency, the pre-optimized operating map comprising operating points of the electric motor,

(b) providing an operating relationship between operating points of the pre-optimized operating map and audible and/or noticeable vibrations (Noise Vibration Harshness, NVH for short) of at least one component of the electric drive system for at least a partial range of operating points of the pre-optimized operating map,

(c) determining at least one condition of a maximum permissible deterioration in efficiency when changing operating points of the pre-optimised operating map,

(d) changing operating points of the pre-optimized operating map in at least one partial operating range of the pre-optimized operating map on the basis of the operating context in order to reduce the audible and/or perceptible vibrations in the at least one partial operating range, wherein the at least one condition is met,

(e) outputting the modified pre-optimised operating map as an optimised operating map, and

(ff) Using the output optimized operating map (5) to control the operation of the electric motor (12) of the electric drive system (11) of the motor vehicle (10).

As a result, the method according to the invention provides an operating map that is optimized in the direction of efficiency and NVH, which, when used to control the electric motor in a motor vehicle with an electric drive system, reduces audible and/or noticeable vibrations of the electric drive system during operation and at the same time high efficiency. The solution takes advantage of the unique advantage of electric motors in that the controls of electric motors are highly adjustable and offer high optimization potential for electric drive systems in several directions. In the present case, this optimization potential is used to implement the optimization of the NVH potential at least in a partial operating area, in particular the most critical part, of the operating map or control map pre-optimized for efficiency.

In particular, the reduction of the audible and/or noticeable vibrations in the at least one partial operating range can be accompanied by a loss of efficiency in the at least one partial operating range. This means that the optimization of the operating map in the direction of reduced audible and/or noticeable vibrations is not carried out entirely without disadvantage, even if this is lower than in the prior art, but in the optimized operating map at the changed operating points with a disadvantage compared to the pre-optimized one Operating map is accompanied by reduced efficiency. Accordingly, the operating points can be manipulated by changing the operating parameters of the electric motor at the operating points to the detriment of efficiency, but thus in favor of lower vibrations.

[0010] In order to compensate for this disadvantage or to take it into account when changing the operating points so that the operating map pre-optimized for efficiency does not lose its high efficiency and thus the high range of the motor vehicle that is made possible, the method according to the invention provides the condition of a maximum permissible deterioration in efficiency for changing the operating points of the pre-optimized operating map. The condition therefore specifies how much the efficiency in the partial operating range can be reduced compared to the efficiency achieved by the pre-optimization or provided by the pre-optimized operating map in order to achieve an NVH reduction. In this way, an NVH optimization, i.e. a reduction in audible and/or noticeable vibrations, can be combined with an efficiency optimization of the operating map of the electric motor. This results in an operating map that is optimized for NVH and efficiency and balanced due to the contradictory nature of the two optimization goals.

The condition can advantageously be a maximum permissible deterioration in efficiency of at most 20%, very particularly at most 15%, and more particularly at most

10% and especially by a maximum of 5% compared to an efficiency of operating points of the pre-optimized operating map.

For example, several different conditions of a maximum permissible deterioration in efficiency when changing the operating points of the pre-optimized operating map can be provided. This means that different conditions can be created in individual operational areas. The different conditions differ in terms of the maximum permissible deterioration in efficiency. It is also possible to provide different optimized operating maps depending on the different conditions, i.e. in particular to carry out method steps (d) and (e) several times for different conditions. In this way, the motor vehicle, in particular the driver, can be offered different driving modes. For example, a quasi-silent mode or comfort mode in which the maximum permissible reduction in efficiency can be very large, for example up to 20%. Another driving mode can be, for example, a combined comfort/efficiency mode, in which the maximum permissible efficiency degradation is up to 5% or 10%, so that there is a mixture of high efficiency and NVH reduction. Again, another driving mode can be a sport mode, in which a maximum permissible reduction in efficiency of at most 1 or 2% is selected so that the greatest possible performance of the electric drive system can be accessed for particularly sporty driving, while noise plays a rather subordinate role in sporty driving play, which are therefore more accepted.

The operating map of an electric motor is understood to mean, in particular, a majority of operating points or a totality of all operating points of the electric motor. The operating points can be organized in any form by the operating map, for example in a table, in the form of one or more functions, in the form of two- or three-dimensional diagrams, any combination of the aforementioned or the like. The operating points are defined in particular by the torque and the speed. The operating map can in particular be represented two-dimensionally in a known manner, with the operating points of the electric motor spanning the operating map over the torques and speeds of the electric motor plotted on axes.

[0014] The initial operating map mentioned later refers to the operating map which serves or can be provided as a starting point for the method. In other words, the initial operating map is the originally provided operating map that is optimized by the method. The pre-optimized operating map is the initial operating map pre-optimized for efficiency. The optimized operating map is the result of the process, i.e. the initial operating map optimized by the process after its pre-optimization. The optimized operating map is at least partially optimized compared to the pre-optimized operating map in the direction of reduced audible and/or noticeable vibrations of the electric drive system of the motor vehicle.

The output of the optimized operating map in method step (e) is carried out in particular for use in the electric motor of the electric drive system of the motor vehicle or a corresponding control unit of the electric motor. The output can take various forms. For example, the output can involve storing, sending and/or displaying the optimized operating map. In addition, the method can of course also include the use of the optimized operating map in the electric motor of the electric drive system of the motor vehicle.

[0016] It is not necessary, but possible, to carry out all the process steps of the process according to the invention in the order indicated by the numbering of process steps (a) to (e). Individual process steps can also be carried out in a different order than this. For example, process step (a) can be carried out before or after process step (b). Process steps can also be carried out simultaneously. For example, process steps (a) and (b) can be carried out simultaneously. The numbering of process steps (a) to (e) serves only to provide a better overview.

visibility.

Advantageously, the operating context can be given by a force map, which includes forces occurring during operation of the electric motor on the at least one component of the electric drive system for the at least a partial range of operating points of the pre-optimized operating map. The force map of the at least one component of the electric drive system is in particular a majority or totality of forces occurring during operation of the electric motor on at least one, several or all components of the electric drive system or on components of one or more components of the electric drive system, depending on the operating points passed through understood. These forces can be stored in the form of force points or force characteristics. The force points can be organized in any form by the force map, for example in a table, in the form of one or more functions, in the form of two- or three-dimensional diagrams, any combination of the aforementioned or the like. The force points can be defined, for example, by specifying the force in Newtons occurring on the at least one component over one or more operating parameters of the electric motor, for example a current intensity, a phase angle, etc. The method according to the invention makes use of the fact that the force map provides information about the audible and/or noticeable vibrations at the operating points by characterizing the forces occurring over the operating points or depending on the operating points. In other words, the forces that occur and are known from the force map correlate at least partially with the audible and/or noticeable vibrations at the respective operating points. As a result, in method step (d), the operating points of the pre-optimized operating map can be changed in at least a partial operating range, in particular an area that is particularly critical in relation to the audible and/or noticeable vibrations or that limits driving comfort, of the pre-optimized operating map on the basis of the force map provided to reduce the audible and/or noticeable vibrations in the at least one partial operating range, whereby the at least one condition is met.

[0018] It is also possible for the method to further comprise generating the force map based on a simulation model of the at least one component, in particular the electric motor and further in particular the entire electric drive system or the entire motor vehicle. Because a simulation model is used, the force map can be determined non-destructively, quickly and precisely, instead of carrying out a real measurement in the motor vehicle. The force map can advantageously be generated on the basis of a finite element analysis.

In principle, it can also be provided that the method is carried out or repeated for different temperatures and/or vibration orders. Force maps can be provided for different temperatures and/or vibration orders.

Advantageously, the at least one component can be an electric drive component of the electric drive system. It can be, for example, the electric motor, a traction battery, an inverter, power electronics and/or a transmission of the electric drive system.

It is particularly advantageous if the at least one component of the electric drive system is the electric motor or a component of the electric motor of the electric drive system. Then the operating context, in particular the force map, is provided for the electric motor or at least a component of the electric motor. Even the audible and/or noticeable vibrations of the electric motor, which can particularly impair driving comfort, can be directly reduced using the method according to the invention. For example, the component can be a stator of the electric motor. In this respect, the method can also be specified as a method for reducing the audible and/or noticeable vibrations of the electric motor.

[0022] Advantageously, the method is also carried out outside the motor vehicle. This enables optimization of the pre-optimized operating map or, as will be explained in more detail later, an initially provided initial operating map of the electric motor of the electric drive system before later online use in the electrically driven motor vehicle. The execution of the method outside the motor vehicle can also be referred to as offline. Advantageously, individual electric motors or individual motor vehicles can be optimized in advance and the optimized operating maps can then be used when using them online. Advantageously, by executing the method outside the motor vehicle, no (CPU) resources, in particular no computing resources of control devices, of the motor vehicle are tied up. Furthermore, the motor vehicle does not have to have such cost-intensive resources in order to be able to provide an operating map optimized according to the invention.

The method can optionally use a further method step after method step (b), in which the audible and/or noticeable vibrations in the at least partial range of operating points of the operating range are determined on the basis of the operating context, in particular the force map. Then the audible and/or noticeable vibrations in this or an entire area of the operating map are known.

In addition to the above or as an alternative to the above further method step, the method can advantageously include the step of selecting the at least one partial operating range. The partial operating area can be selected from the entire operating area or a set of partial operating areas, which can divide the entire operating area, for example, in a predefined manner. Several sub-operational areas can also be selected. The selection can still be made according to specified criteria. It is particularly advantageous if the at least one partial operating range is selected when it exceeds a predefined limit value of audible and/or noticeable vibrations. When using a force map, the limit value of the audible and/or noticeable vibrations can also be predefined by a limit value of the forces that occur, which is considered equivalent due to the correlation between forces and vibrations. The respective predefined limit value can be determined, for example, for individual operating points or a large number of operating points, for example in the form of an average or median. This can ensure that only operating points are changed in partial operating areas that cause high oscillations in operation that should therefore preferably be reduced. Accordingly, in addition to the condition of a maximum permissible deterioration in efficiency, the criterion of a minimum NVH is added so that not all conceivable vibrations are removed that have little or no significant influence on driving comfort.

In principle, the pre-optimized operating map can also be optimized in the entire operating range of the electric motor. However, it can be advantageous to optimize the pre-optimized operating map of the at least one electric motor for NVH only in a certain operating range, which can be ensured by the condition of the maximum permissible deterioration in efficiency and the above condition of the minimum NVH.

It is also advantageous if step (d) is carried out under the condition that a torque and a speed of the electric motor are maintained by the pre-optimized operating map. In this way it can be ensured that the pre-optimized operating map is only changed in a specific, particularly advantageous parameter range with regard to the pre-optimization for maximum efficiency. Further conditions can also be used to optimize the map, which in turn can depend on specific operating parameters of the electric motor. For example, a maximum available voltage and a maximum permitted current intensity can be specified as operating parameters of the electric motor, which must be adhered to in step (d) in order to obtain actually applicable results.

[0027] Advantageously, in step (d) at least one or more operating parameters can be used

Operating parameters of the electric motor can be changed. The at least one operating parameter can be a voltage and/or a current strength of the electric motor. Meanwhile, other possible conditions can be met, such as a permissible maximum voltage and current.

[0028] Advantageously, the method for providing the operating map of the electric motor pre-optimized for efficiency can include the step of providing and pre-optimizing an output operating map by maximizing at least one efficiency function of the at least one component of the drive system. In particular, a method for maximizing the torque per watt (MTPW for short) can be used to pre-optimize for maximum efficiency.

Advantageously, it can be provided that the initial operating map is pre-optimized by varying at least one operating parameter of the electric motor. Advantageously, several of the operating parameters mentioned herein, such as current and voltage, of the electric motor can be varied while maintaining possible conditions, for example an allowable maximum voltage and current.

[0030] In this case, the at least one efficiency function can particularly advantageously be a system efficiency function which is a combination of a first efficiency function of the electric motor of the electric drive system and at least one further efficiency function of at least one further electrical component of the electric drive system. This means that the electric motor is not automatically pre-optimized for maximum efficiency. Instead, with the at least one electric motor and the at least one further electrical component, in particular drive component, a larger part of the electric drive system, in particular the entire electric drive system, is taken into account when pre-optimizing the efficiency for the electrically driven motor vehicle. For this purpose, the system efficiency function is provided which combines the efficiency functions of the at least one electric motor and the efficiency function of the at least one further electrical drive component. This has proven to be advantageous because higher losses in other electrical drive components, for example in an inverter, can cancel out efficiency increases in the electric motor in the overall view. With the present improvement, however, possible losses or efficiencies of other electrical drive components can be included in the process of efficiency optimization of electric motors, so that a system efficiency optimized for the entire electric drive system, in particular at least almost optimal, can be achieved.

It can be provided that the further efficiency function depends on at least one operating parameter of the electric motor. The operating parameters can be, for example, a voltage of the electric motor, a current strength of the electric motor, a speed of the electric motor, etc. This makes it possible to determine the further efficiency function depending on the operating parameters of the electric motor. A change in one of the aforementioned operating parameters always leads to a change in the efficiency of the electric motor and of the at least one further electrical component. Of course, the further efficiency function can also depend on operating parameters of the at least one further electrical component. In the case of an inverter, these (intrinsic) operating parameters can be, for example, an electrical component, a switching frequency, a modulation index and/or the modulation method used (for example Space Vector Pulse Width Modulation (SVPWM), Discontinuous Pulse Width Modulation (DPWM), Selective Harmonic Elimination Pulse Width Modulation ( SHEPWM) etc.).

[0032] Advantageously, a loss function can be used for the system efficiency function, wherein the loss function is minimized to maximize the system efficiency. Likewise, loss functions can be used for the first efficiency function and the further efficiency functions. The use of such loss functions for the first efficiency function and the further efficiency function allows a simple combination of the two efficiency functions by simple addition to one another. Accordingly, the system efficiency function for the

Optimization of the initial operating map can be calculated using comparatively simple mathematical operations.

The method can also use a further operating relationship between the operating map and the at least one further electrical component of the electric drive system. A further operating context of the further electrical component is a connection between the electric motor and the further electrical component, created in particular by one or more operating parameters and/or operating functions with the operating map of the electric motor, or an operational dependence of the further electrical component on the electric motor or its output. Operating map understood, which is caused by a common connection or functionality in the electric drive system. The further operating context of the further electrical component can also be represented by an operating map or the operation of the further electrical drive component can be represented by an operating map.

It is also advantageous if the at least one further electrical component is an inverter. In particular, only the electric motor of the electric drive system and the inverter can be taken into account in the method as electric drive components of the electric drive system in order to pre-optimize the output operating map of the at least one electric motor, because these two different types of electric drive components have the greatest influence on the system efficiency. However, other electric drive components that are not an electric motor and not an inverter, such as traction batteries, power electronics, transmissions, etc., can also be taken into account, whose respective efficiency functions can be used to provide the system efficiency function by combining them with the other efficiency functions.

In particular, it is also advantageous if the initial operating map is pre-optimized to a lower than maximum efficiency of the electric motor in favor of a higher system efficiency. In other words, a deterioration in the efficiency of the electric motor is deliberately permitted in order to gain an efficiency gain in the at least one further electrical component, which exceeds the efficiency loss in the electric motor and thus ensures a gain in the system efficiency or overall efficiency of the electric drive system. Compared to an isolated optimization of the electric motor or a ban on deterioration when optimizing the electric motor or a pre-optimized operating map of the electric motor, a higher system efficiency can be achieved.

Use in the vehicle can be implemented by a switch, which can be physical or electronic, for example, and/or a function in the motor vehicle. Actuating the switch and/or activating the function can activate the optimized operating map in the motor vehicle obtained or output by the method according to the invention. As a result, the motor vehicle can drive in a quasi or practically noiseless and yet efficient mode, particularly at the driver's or occupant's request.

The present invention also relates to a system for optimizing the efficiency of an electric drive system of a motor vehicle and for reducing the audible and/or noticeable vibrations of the electric drive system of the motor vehicle by outputting an optimized operating map for the electric motor of the electric drive system. The system has:

- a deployment module for

(a) Providing an operating map of the electric motor that is pre-optimized for efficiency, the pre-optimized operating map comprising operating points of the electric motor, and

(b) providing an operating relationship between operating points of the pre-optimized operating map and audible and/or perceptible vibrations of at least one component of the electric drive system for at least a partial range of operating points of the operating map,

- a determination module for

(c) determining at least one condition of a maximum permissible deterioration in efficiency when changing operating points of the pre-optimized operating map,

- a change module for

(d) changing operating points of the pre-optimized operating map in at least one partial operating range of the pre-optimized operating map based on the operating context in order to reduce the audible and/or noticeable vibrations in the at least one partial operating range, wherein the at least one condition is met, and

- an output module for

(e) outputting the changed pre-optimized operating map as an optimized operating map, and

(ff) Using the output optimized operating map (5) to control the operation of the electric motor (12) of the electric drive system (11) of the motor vehicle (10).

A system according to the invention therefore brings with it the same advantages as have been explained in detail with reference to the method according to the invention. In particular, the system can be set up or designed to carry out the method according to the invention.

The modules can, for example, each be implemented by a separate computer program code or jointly by a common computer program code and/or by separate or common functional units of a computer. It is also possible for individual modules to be implemented in a common module, for example the provision module and the destination module. The system can in particular include one or more computers or be formed by one or more computers, which can have the individual modules.

The present invention also provides a computer program product comprising instructions which, when the program is executed by a computer, cause it to carry out the method according to the invention.

A computer program product according to the invention thus brings with it the same advantages as have been explained in detail with reference to the method according to the invention.

[0042] The computer program product can be a computer program per se or a product, such as a computer-readable data storage device, on which a computer program for carrying out the method can be stored.

Further advantages, features and details of the invention emerge from the following description, in which exemplary embodiments are described in detail with reference to the drawings. It shows schematically:

1 shows an electrically driven motor vehicle, FIG. 2 shows an embodiment of a system according to the invention, and FIG. 3 shows an embodiment of a method according to the invention.

Identical or functionally identical elements are each designated with the same reference numeral in FIGS. 1 to 3.

1 shows schematically an electrically driven motor vehicle 10 with an electric drive system 11. The electric drive system 11 has an electric motor 12.

[0049] In addition to the above-mentioned component in the form of the electric motor 12, the electric drive system 11 can of course comprise further components 13, in particular electric drive components such as a traction battery, an inverter, power

electronics, gears, etc., which, however, are not all shown in FIG. 1 for the sake of clarity, but are represented by component 13.

For the sake of simplicity and as a preferred exemplary embodiment, the following explanation of exemplary embodiments of a system 20 according to the invention (see FIG. 2) and a method 30 according to the invention (see FIG. 3) is limited to the electric drive component 12 in the form of only one as an example Electric motor 12 and the further component 13 in the form of an inverter 13, because when the electric motor 12 and inverter 13 are taken into account for a pre-optimization of an output operating map 1, a particularly high system efficiency of a pre-optimized operating map 2 can be achieved (see Fig. 2).

2 shows schematically a system 20 in the form of a computer with a provision module 21, a determination module 22, a change module 23 and an output module 24, the system 20 being located outside the motor vehicle 10 shown in FIG. The system 20 is used to carry out the method 30 according to the invention according to the exemplary embodiment of FIG ", NVH for short) of the electric motor 12 of the electric drive system 11 of the motor vehicle 10 of FIG. 1.

The provision module 21 serves to provide an operating map 2 of the electric motor 12 that is pre-optimized for efficiency and an operating context 3, in particular in the form of a force map 3, which occurs when the electric motor 12 is operated with the pre-optimized operating map 2 and can be generated accordingly. The force map 3 indicates the forces occurring during operation of the electric motor 12 on the electric motor 12 or one or more of its components, for example on its stator, for at least a partial range, preferably the entire range, of operating points of the pre-optimized operating map 2.

To provide the pre-optimized operating map 2, the method can start or start from an initial operating map 1. Such an output operating map 1 cannot therefore be optimized for efficiency or in another direction, or at least not completely pre-optimized in such a direction. However, the output operating map 1 can be pre-optimized for optimal efficiency of the electric motor 12, so that the pre-optimized operating map 2 is obtained.

To pre-optimize the output operating map 1 for maximum efficiency, a system loss function (not shown) can be used, which is composed of efficiency functions in the form of loss functions of the electric motor 12 and the inverter 13. This system loss function can be minimized, in particular by the provision module 21, in order to optimize the output operating map 1 such that an overall efficiency or system efficiency of the electric drive system 11 can be increased. For this purpose, at certain operating points in the initial operating map 1, the efficiency of the electric motor 12 is reduced in favor of a higher efficiency in the inverter 13, although the gain in efficiency on the part of the inverter 13 predominates, so that the overall system efficiency is higher. As a result, the provision module 21, which alternatively also acts as an optimization module (optimization of efficiency), as shown in FIG. 2, produces an operating map 2 that is pre-optimized with regard to the system efficiency.

[0055] In addition to the provision module 21, there is a determination module 22 which determines one of the several conditions 4 of maximum permissible efficiency deterioration(s) in the event of (further) changes to operating points of the pre-optimized operating map 2. This is because the pre-optimized operating map 2 now has (essentially) maximum efficiency when it is used in a corresponding control unit of the electric motor 12. Any further change in a different direction, such as the reduction of the audible and/or perceptible vibrations provided here, results in a reduction in efficiency. The condition(s) 4 ensure that the previous step of the pre-optimization or the efficiency obtained thereby is not

is lost to the detriment of NVH reduction, but rather a technical balance is maintained between both directions of optimization.

The change module 23 now receives the condition(s) 4, the pre-optimized operating map 2 and the force map 3 and, on this basis, changes the operating points of the pre-optimized operating map 2 in at least a partial operating range of the pre-optimized operating map 2 in favor of lower hearing and/or more noticeable vibrations of the electric motor 12, whereby condition (s) 4 is or are met. This can be done in such a way that the operating points of the pre-optimized operating map 2 are compared with a limit value of the forces occurring at the operating points according to the force map 3 in favor of reduced audible and/or noticeable vibrations of the electric motor 12. If the limit value is exceeded, which can be chosen so that its exceedance leads to audible and/or noticeable vibrations during driving that are classified as critical for driving comfort, the operating points that cause these vibrations can be changed as long as the Condition(s) 4 are/are met. In this way, the partial operating range can be defined as an area with particularly critical operating points with regard to audible and/or noticeable vibrations.

As a result, the change module 23, which can alternatively be referred to as an optimization module (optimization of the NVH) and, as shown in FIG. 2, generates an operating map 5 that is now also optimized with regard to NVH in addition to the optimization for system efficiency This optimized operating map 5 is output by an output module 24, which, as an alternative to the representation in FIG. 2, can also be implemented together with the change module 23.

1 and 2 can be seen by an arrow between FIGS. 1 and 2, the now optimized operating map 5 is output or transferred to the electric drive system 11 and then in the motor vehicle 10, in particular by a corresponding control or a control device is used. On the one hand, this allows operation of the motor vehicle 10 with the electric motor 12 operating virtually or practically noiselessly in local and critical NVH areas in relation to driving comfort, because these critical NVH areas are optimized in the optimized operating map 5 compared to the initial operating map 1 are. On the other hand, outside of these local and critical NVH areas, the electric drive system 11 can work with maximum efficiency. Finally, even in the NVH-optimized areas, a comparatively high efficiency can be maintained thanks to condition 4 of the maximum allowable efficiency degradation. Accordingly, the described optimization of the output operating map 1 of the electric motor 12 is carried out offline by the system 20. However, the result in the form of the optimized operating map 5 is then implemented in the motor vehicle 10 and used online, i.e. while the motor vehicle 10 is driving.

[0059] Figure 3 shows a further example of the already explained method 30 according to the invention in the form of method steps 31...37 with further details.

[0060] In method step 31, the initial operating map 1 is pre-optimized for maximum efficiency by maximizing the torque per watt. In method step 32, conditions for the subsequent optimization are set up by the determination module 22. The conditions include at least the condition of the maximum permissible deterioration in efficiency, i.e. in particular a specification of a permitted difference, for example in %, of the efficiency after changing operating points compared to the maximum efficiency achieved by the pre-optimization. Further conditions can in particular be that a torque and a speed of the at least one electric motor 12 are maintained by the pre-optimized operating map 2. Still further conditions can specify the maximum available voltage and a maximum permitted current as operating parameters of the electric motor 12.

[0061] Parallel to or, alternatively, before or after the method steps 31 and 32, the method steps 33, 34 and 35 are carried out one after the other. In the method step 33, a

Simulation model of the electric motor 12 is provided or generated. This can be done on the basis of a finite element analysis. In the method step 34, the force map 3 is then generated on the basis of an operating simulation of the simulation model of the electric motor 12 with the pre-optimized operating map 2. The force map 3 can represent the forces that occur in a time-space order. The force map 3 can be spanned by current components Id, Iq of the current with force parameters, for example in Newtons, over each operating point. In the method step 35, the force map 3 obtained in this way is then made available for optimization.

In method step 36, the optimization of the pre-optimized operating map 2 now takes place, whereby the operating points selected, as described above, in the pre-optimized operating map 2 can be optimized in compliance with the previously defined conditions. For this purpose, the respective operating parameters of the electric motor 12, such as voltage and current, can be adjusted. In method step 37, the optimized operating map 5 is output for use in the electric drive system 11 of the motor vehicle 10.

[0063] The above explanations of the embodiments describe the present invention exclusively by way of examples.

REFERENCE SYMBOL LIST

1 output operating map

2 pre-optimized operating map

3 Operating context, force map

4 Condition of maximum permissible deterioration in efficiency 5 optimized operating map

10 motor vehicle

11 electric drive system

12 component, electric drive component, electric motor

13 additional components, additional electrical drive components, inverters

20 system

21 Deployment Module

22 determination module

23 change module

24 output module

30 procedures

31-37 procedural steps

Claims (1)

Patent claims 1. Computer-implemented method (30) for optimizing the efficiency of an electric drive system (11) of a motor vehicle (10) and for reducing the audible and/or noticeable vibrations of the electric drive system (11) of the motor vehicle (10) by outputting an optimized operating map ( 5) for an electric motor (12) of the electric drive system (11), the method (30) being characterized by the following steps: (a) providing an operating map (2) of the electric motor (12) that is pre-optimized for efficiency, the pre-optimized operating map (2) comprising operating points of the electric motor (12), (b) providing an operating relationship (3) between operating points of the pre-optimized operating map (2) and audible and/or noticeable vibrations of at least one component (12, 13) of the electric drive system (11) for at least a partial range of operating points of the pre-optimized operating map ( 2), (c) determining at least one condition (4) of a maximum permissible deterioration in efficiency when changing operating points of the pre-optimized operating map (2), (d) changing operating points of the pre-optimized operating map (2) in at least one partial operating range of the pre-optimized operating map (2) on the basis of the operating context (3) to reduce the audible and/or perceptible vibrations in the at least one partial operating range, wherein the at least one condition is met, (e) outputting the changed pre-optimized operating map (2) as an optimized operating map (5), and (f) Using the output optimized operating map (5) to control the operation of the electric motor (12) of the electric drive system (11) of the motor vehicle (10). 2. Computer-implemented method (30) according to claim 1, characterized in that the operating context (3) is given by a force map (3), which during operation of the electric motor (12) on the at least one component (12, 13) of the electric drive system (11) includes forces occurring for at least a partial range of operating points of the pre-optimized operating map (2). 3. Computer-implemented method (30) according to claim 2, characterized in that the method (30) further comprises generating the force map (3) based on a simulation model of the at least one component (12, 13) of the electric drive system (11). 4. Computer-implemented method (30) according to one of the preceding claims, characterized in that the component (12, 13) of the electric drive system (11) is the electric motor (12) or a component of the electric motor (12). 5. Computer-implemented method (30) according to one of the preceding claims, characterized in that the method (30) is carried out outside the motor vehicle (10). 6. Computer-implemented method (30) according to one of the preceding claims, characterized in that the condition is a maximum permissible deterioration in efficiency of at most 20% compared to an efficiency of operating points of the pre-optimized operating map (2). 7. Computer-implemented method (30) according to one of the preceding claims, characterized in that the method (30) further comprises the step of selecting the at least one partial operating area, wherein the at least one partial operating area 10. 11. 12. 13. Austrian AT 526 204 B1 2024-03-15 Range is selected if it exceeds a predefined limit of audible and/or noticeable vibrations. Computer-implemented method (30) according to one of the preceding claims, characterized in that step (d) is carried out under the condition that a torque and a speed of the electric motor (12) are maintained by the pre-optimized operating map (2). Computer-implemented method (30) according to one of the preceding claims, characterized in that the method (30) for providing the operating map (2) of the electric motor (12) pre-optimized for efficiency includes the step of providing and pre-optimizing an output operating map (1) by maximizing at least one efficiency function of at least one component (12, 13) of the drive system (11). Computer-implemented method (30) according to claim 9, characterized in that the at least one efficiency function is a system efficiency function, which consists of a first efficiency function of the electric motor (12) of the electric drive system (11) and at least one further efficiency function of at least one further electrical component (13). of the electric drive system (11) is combined. Computer-implemented method (30) according to claim 10, characterized in that the at least one further electrical component (13) is an inverter (13). Computer-implemented method (30) according to claim 10 or 11, characterized in that the initial operating map (1) is pre-optimized to a lower than maximum efficiency of the electric motor (12) in favor of a higher system efficiency. System (20) for optimizing the efficiency of an electric drive system (11) of a motor vehicle (10) and for reducing the audible and/or noticeable vibrations of the electric drive system (11) of the motor vehicle (10) by outputting an optimized operating map (5) for the electric motor (12) of the electric drive system (11), the system (20) being characterized by: - a provision module (21) for (a) providing an operating map (2) of the electric motor (12) that is pre-optimized for efficiency, the pre-optimized operating map (2) comprising operating points of the electric motor (12), and (b) providing an operating relationship (3) between operating points of the pre-optimized operating map (2) and audible and/or noticeable vibrations of at least one component (12, 13) of the electric drive system (11) for at least a partial range of operating points of the operating map (2 ), - a determination module (22) for (c) determining at least one condition (4) of a maximum permissible deterioration in efficiency when changing operating points of the pre-optimized operating map (2), - a change module (23) for (d) changing operating points of the pre-optimized operating map (2) in at least one partial operating range of the pre-optimized operating map (2) based on the operating context (3) to reduce the audible and/or noticeable vibrations in the at least one partial operating range, wherein the at least one condition is adhered to, as well - an output module (24) for (e) outputting the changed pre-optimized operating map (2) as an optimized operating map (5), and (f) Using the output optimized operating map (5) to control the operation of the electric motor (12) of the electric drive system (11) of the motor vehicle (10). 14. Computer program product, comprising instructions which, when the program is executed by a computer, cause it to carry out the computer-implemented method (30) according to one of claims 1 to 12. 1 sheet of drawings