WO2023205833A1

WO2023205833A1 - Method for reducing the audible and/or perceptible vibrations in an electrical drive system of a motor vehicle

Info

Publication number: WO2023205833A1
Application number: PCT/AT2023/060137
Authority: WO
Inventors: Mehdi MEHRGOU; Stefan Maier; Inigo GARCIA DE MADINABEITIA MERINO; Mohamed Essam AHMED; Safa MAHROUS; Francesco Duchi
Original assignee: Avl List Gmbh
Priority date: 2022-04-26
Filing date: 2023-04-25
Publication date: 2023-11-02
Also published as: AT526132A1

Abstract

The present invention relates to a method (30) and a system (20) for reducing the audible and/or perceptible vibrations in an electrical drive system (11) of a motor vehicle (10) by outputting an optimized family of operating characteristic curves (3) for an electric motor (12) of the electrical drive system (11).

Description

Method for reducing the audible and/or noticeable vibrations of an electric drive system of a motor vehicle

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

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.

Various approaches are known from the prior art to achieve this goal, for example by adapting the geometry of the motor vehicle or adding damping elements in the motor vehicle. This is, for example, from the IEEE Paper XP011715844, “Electromagnetic Vibration and Noise of the Permanent-Magnet Synchronous Motors for Electric Vehicles: An Overview” Deng, W et al., IEEE Transactions on Transportation Electrification, Vol. 5, No. 1, March 1, 2019, p. 59 - 70 known.

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. The above object is achieved by a method with the features of claim 1, a use with the features of claim 13, a system with the features of claim 14 and a computer program product with the features of claim 15. Further features and details of the invention result from the subclaims, 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 use according to the invention, the system according to the invention and the computer program product according to the invention and vice versa, so that reference is always made to each other with regard to the disclosure of the individual aspects of the invention or can be.

According to the invention, a method is provided for reducing the audible and/or noticeable vibrations of an electric drive system of a 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 output operating map of the electric motor, wherein the output operating map includes operating points of the electric motor,

(b) Providing a force map of at least one component of the electric drive system for the operation of the electric motor with the provided output operating map, wherein the force map shows the forces occurring during operation of the electric motor on the at least one component of the electric drive system for at least a partial range of operating points of the Output operating map includes,

(c) changing operating points of the initial operating map in at least one partial operating range of the initial operating map based on the force map provided to reduce the audible and/or noticeable vibrations in the at least one partial operating range, and

(d) Outputting the changed output operating map as an optimized operating map. The method according to the invention, which can in particular be a computer-implemented method or can be carried out on a computer or several computers, thus provides an optimized operating map, which, when used to control the electric motor in a motor vehicle with an electric drive system, has reduced hearing and noise /or noticeable vibrations of the electric drive system during operation. 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.

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 and/or the current and phase angle, i.e. the angle from the stator to the rotor of the electric motor. 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 or current and phase angles of the electric motor plotted on axes.

The initial operating map means the operating map which serves or is provided as a starting point for the method. In other words, the output operating map is the operating map that is optimized by the method. The optimized operating map is the result of the process, i.e. the initial operating map optimized by the process. Compared to the initial operating map, the optimized operating map is at least partially in the direction of reduced audible and/or noticeable vibrations of the electric drive system Motor vehicle optimized.

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 (c), the operating points of the initial operating map can be changed in at least a partial operating range, in particular an area of the initial operating map that is particularly critical in relation to the audible and/or noticeable vibrations or that limits driving comfort, on the basis of the provided force map to reduce the audible and / or noticeable vibrations in the at least one partial operating range.

The optimized operating map is output in method step (d) 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. This is how it can be The output involves, for example, 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.

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

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. The force map for the electric motor or at least a component of the electric motor is then provided. 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 referred to as a method for reducing the audible and/or noticeable vibrations of the electric motor.

Advantageously, the method is also carried out outside the motor vehicle. This enables the initial operating map of the electric motor of the electric drive system to be optimized 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 are optimized in advance and the optimized operating maps are then used when they are used 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.

In particular, the reduction in 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 initial 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 opposite the initial 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.

The method can optionally use a further method step between method steps (b) and (c), 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 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. This further process step can be carried out in particular between process steps (b) and (c). 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 that the at least one partial operating range is selected if it exceeds a predefined limit value of forces occurring and/or falls below a predefined limit value of a loss of efficiency. 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 and therefore preferably need to be reduced, and/or only operating points are changed in partial operating areas in which the reduction in audible and/or noticeable oscillations is acceptable There is a loss of efficiency compared to the initial operating map. The combination of both limit values is particularly advantageous in order to achieve a middle path between driving comfort and efficiency when optimizing.

In principle, the initial operating map can also be optimized over the entire operating range of the electric motor. However, it can be advantageous to optimize the operating map of the at least one electric motor only in a specific operating range. Such local optimization can be used to exclude certain operating areas in which, for example, optimization can be carried out in a direction other than NVH reduction, for example to maximize the efficiency of the electric motor.

It is particularly advantageous if the initial operating map is or will be optimized for maximum efficiency of the electric drive system, in particular of the electric motor, outside the at least one partial operating range. This means that a local NVH optimization is carried out, in which the initial operating map, which can already be pre-optimized to maximum efficiency or can subsequently be optimized, is only optimized in a specific NVH range that limits driving comfort. This ensures that a high level of driving comfort is achieved with low energy consumption over the entire driving cycle. In particular, a method for maximizing the torque per watt (MTPW for short) can be used to optimize for maximum efficiency. It is also advantageous if step (c) is carried out under the condition that a torque and a speed of the electric motor are maintained from the output operating map. In this way it can be ensured that the initial operating map is only changed in a specific, particularly advantageous parameter range with regard to the previously mentioned prior 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 (c) in order to obtain actually applicable results.

Advantageously, at least one operating parameter or several operating parameters of the electric motor can be changed in step (c). The at least one operating parameter can be a voltage and/or a current strength of the electric motor. Meanwhile, possible conditions can be maintained, such as a permissible maximum voltage and current.

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.

For the determination and selection of the force map or force maps for use in the method according to the invention, it can advantageously be provided that the method further comprises the step: generating a first data set of different ones specific for the electric motor Force maps to which different time orders and spatial orders are assigned, the force maps comprising forces occurring on at least one component of the electric motor during operation of the electric motor for different operating parameters of the electric motor. In addition, the method can include the following step: providing, in particular generating, a second data set specific to the electric motor, which assigns different sound values of the at least one component of the electric motor to different spatial orders and time orders of the first data set. Finally, the method can include the following step: determining the data of the audible and/or noticeable vibrations of the electric motor by selecting force maps from the first data set based on a comparison of the sound values of the second data set with a predetermined sound limit value. The force maps selected in this way can be provided for the method according to the invention in step (b).

The aforementioned additional method steps thus provide data from audible and/or noticeable vibrations of the electric motor, which are used to optimize the initial operating map of the electric motor. This ensures that only those audible and/or noticeable vibrations whose sound corresponds to or is above a predetermined sound limit are reduced.

The sound limit value can be chosen so that only those audible and/or noticeable vibrations or such NVH behavior are included in the data, which during ferry operation of the motor vehicle only result in noises and/or audible by the passengers in the interior of the motor vehicle. or noticeable vibrations. In particular, it is possible to select the sound limit value in such a way that it only includes those audible and/or noticeable vibrations or such NVH behavior that, in ferry operation of the motor vehicle, only cause noises that disturb the passengers of the motor vehicle, i.e. that are sufficiently audible or .loud vibrations or disturbing vibrations, i.e. sufficiently noticeable vibrations in the vehicle interior of the motor vehicle.

Accordingly, the additional process steps enable intelligent NVH data selection based on a special data set, which is referred to herein as the second data set to distinguish it from the first data set, which is in computer calculations known from the prior art are not used or at least not in the manner suggested by the method according to the invention. Accordingly, although it is necessary to provide the second data set, in particular to generate it, which requires a certain amount of effort, a significant reduction in the force maps relevant with regard to NVH and thus supplied to the method in step (b) can be achieved. The fact that only these reduced data, which due to their selection can also be referred to as comfort-relevant NVH data (based on their relevance due to possible noises and vibrations on the motor vehicle, especially in the vehicle interior), are determined, while those that are less relevant to comfort or Irrespective audible and/or noticeable vibrations are excluded, despite the generation of the second data set, the necessary computing time for the method as a whole is significantly reduced compared to the method known from the prior art. The computing time can be reduced from several hours to a few minutes or even seconds.

Time orders and spatial orders are understood here to mean, in particular, dimensionless variables of the electric motor that occur during its operation. The time orders can be derived from the frequencies, in particular excitation frequencies, of the electric motor. The spatial orders can be derived from deformations, in particular on the surface, of at least one component, in particular the stator, of the electric motor. This means that the electric motor can be characterized by the time and spatial orders with regard to the frequency and the deformation as a result of the force acting on it and thus with regard to the audible and / or noticeable vibrations, which also means that the force maps over the time and spatial orders in the first Data set can be correlated. There is preferably a predetermined number of time orders and spatial orders, so that virtually the entire (relevant) operating range of the electric motor is covered by the time orders and spatial orders and can be assigned in terms of time and space.

The respective parameters such as spatial orders, time orders, force maps, sound values, etc. in the first data set and in the second data set can be organized in any form, for example in a table, in the form of one or more functions, in the form of two- or three-dimensional diagrams, one any combination of the above or the like. For example, the first data set can be stored or mapped by a two-dimensional graphical representation or a plot, in which the time orders and spatial orders are plotted on respective coordinate axes and force maps are assigned to these by respective force map points, which in turn with their information in a further two-dimensional graphical representation can be saved or mapped.

Preferably, different spatial orders for different time orders are preselected based on the comparison of the sound values of the second data set with the predetermined sound limit value and the force maps are selected according to the preselected spatial orders. Accordingly, the force maps themselves are not selected in the second data set, but only through the preselection of the respective spatial order and correlation of this preselected spatial order with the associated time order is the appropriate force map selected in the first data set.

The sound limit value can in principle be a limit value for a sound value. Then the spatial orders that exceed the sound limit are preselected for a respective time order and the force maps associated with them are selected. The sound limit value can also be a number of spatial orders per time order, which are to be preselected based on their sound value at a respective time order or frequency. For example, a sound limit value can be set by a number of, for example, three spatial orders per time order. This means that the three spatial orders with the highest sound values are preselected in the second data set for a respective time order or frequency.

It is therefore possible to pre-select the spatial order(s) from all spatial orders of a time order that has the highest sound value(s) of all spatial orders of the respective time order. For each time order, in particular all time orders, those spatial orders are selected which, based on the sound value, have the largest audible and/or noticeable vibrations.

It is also preferred that an operating map of the electric motor is combined with the selected force maps, so that for different Time orders and different spatial orders depending on the operating points of the electric motor operating point force maps are obtained. While the operating maps in particular indicate operating points depending on torque and speed and can indicate the efficiency of the electric motor and the force maps in particular indicate the forces occurring on the electric motor as a function of operating parameters, such as phase angle and current, the operating point force maps indicate the forces occurring Dependence of the operating points or the speed and the torque.

For this purpose, it is preferred that the operating point force maps for different time orders are combined, in particular multiplied, with the sound values of the second data set, so that sound value maps that are dependent on the operating points of the electric motor are obtained for different time orders. The sound value maps thus serve as a kind of NVH map for the different time orders and can therefore preferably be used to further optimize the electric motor.

It is also preferred that the at least one component of the electric motor is a stator or rotor. Because the audible and/or noticeable vibrations of the electric motor typically occur on the stator and rotor and in the air gap between them, the data of the audible and/or noticeable vibrations that particularly impair driving comfort can be determined particularly precisely.

The different spatial orders can indicate different deformations that occur in an air gap between the stator and the rotor of the electric motor. The deformations are in particular deformations of the stator as a result of the forces acting on it. The deformations occur in the form of force waves on the stator and can be visualized. The individual deformations can be a dimensionless specification and the acting forces can be specified by specifying the respective spatial order.

The time orders in turn can represent dimensionless relationships between an excitation frequency of the electric motor or the at least one component, in particular of the stator, of the electric motor and a predetermined reference frequency, in particular a number of rotor revolutions, in particular of the rotor of the electric motor, per second or, in other words, a speed.

Furthermore, it is preferred if the second data set maps a curve of sound values over a frequency, in particular an excitation frequency of the electric motor or the at least one component, in particular of the stator, of the electric motor, for spatial arrangements. The second data set can therefore also be stored or represented by a two-dimensional graphic representation, in which the sound values and the time orders or frequencies that can be assigned to them, in particular excitation frequencies of the electric motor, can be plotted on the coordinate axes of a two-dimensional coordinate system. The individual spatial orders can be plotted as graphs on the coordinate system, so that it can be read which sound value the respective spatial order has at which frequency or time order. With the organization of the first data set and the second data set explained here, a simple comparison between the two data sets is possible. In this case, for individual or all time orders in the first data set, on the basis of the time order or the corresponding frequency in the second data set, the spatial order or those spatial orders can be selected which have the predetermined sound limit value, i.e. in particular can be assessed as disruptive to driving comfort.

It is also preferred that the second data set is generated from a simulation model of the electric motor. The simulation model can be based on a CAD model, for example. To generate the second data set, the at least one component of the electric motor, in particular its stator, can be exposed in the simulation model to artificial forces, in particular tensile and compressive forces, which cause the aforementioned deformations to which the spatial orders are assigned. The forces can be varied along the circumference of the stator in terms of their direction and/or their point of application on the stator. Because of the artificial forces, the surface of the stator is deformed and a sound can be detected that emanates from the stator and thus the electric motor. This sound can be specified in the form of the sound value, which in turn can be, for example, a sound pressure, a sound power, a volume, for example in decibels, or another unit or a combination of units. The invention also relates to the use of an optimized operating map output by the method according to the invention for controlling the operation of an electric motor of an electric drive system of a motor vehicle.

The use 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.

Such use can be implemented by a switch, which can be physical or electronic, for example, and/or a function in the motor vehicle. The actuation of the switch and/or activation of the function can activate the control map in the motor vehicle that is obtained or output by the method according to the invention and is optimized with regard to reduced audible and/or noticeable vibrations. This allows the motor vehicle to drive in a quasi or practically silent mode, particularly at the driver's or occupant's request.

Furthermore, the subject of the present invention is to reduce the audible and/or noticeable vibrations of an electric drive system of a motor vehicle, the system having:

- a deployment module for

(b) Providing a force map of at least one component of the electric drive system for the operation of the electric motor with the provided output operating map, wherein the force map shows the forces occurring during operation of the electric motor on the at least one component of the electric drive system for at least a partial range of operating points of the Output operating map includes a change module for (c) changing operating points of the initial operating map in at least one partial operating range of the initial operating map based on the force map provided to reduce the audible and/or noticeable vibrations in the at least one partial operating range, and

- an output module for

(d) Outputting the changed output operating map as an optimized operating map.

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 change 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 or the use 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.

The computer program product can be a computer program itself or a product, such as a computer-readable data memory, 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 Figures 1 to 3.

Figure 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.

In addition to the component mentioned, in particular the electric drive component, in the form of the electric motor 12, the electric drive system 11 can of course have further components 13, such as a traction battery, an inverter, power electronics, transmission, etc., which, however, are not all shown in the figure for the sake of clarity 1 are shown, 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, 13 in the form of, for example, only one electric motor 12.

Figure 2 shows schematically a system 20 in the form of a computer with a provision module 21, a change module 22 and an output module 23, the system 20 being located outside the motor vehicle 10 shown in Figure 1. The system 20 is used to carry out the method 30 according to the invention according to the exemplary embodiment of FIG driven motor vehicle 10 of FIG. 1. The provision module 21 serves to provide an output operating map 1 of the electric motor 12 and a force map 2 of the electric motor 12 for the operation of the electric motor 12 with the provided output operating map 1 or, in other words, a force map 2 that is used during operation of the electric motor 12 occurs with the output operating map 1 and can be generated accordingly. The force map 2 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 initial operating map 1. The output operating map 1 can advantageously be (pre)optimized for optimal efficiency of the electric motor 12.

The change module 22 receives the initial operating map 1 and the force map 2 and, on this basis, changes the operating points of the initial operating map 1 in at least a partial operating range of the initial operating map 1 in favor of lower audible and / or more noticeable vibrations of the electric motor 12. This can For example, this can happen in such a way that the operating points of the initial operating map 1 are compared with a predetermined limit value of the forces occurring at the operating points according to the force map 2 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 in ferry operations that are classified as critical for ride comfort, the operating points that cause these vibrations can be changed. 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.

Preferably, a limit value for a loss of efficiency can also be used, which is used in addition to selecting the partial operating range. This is because the modification in the direction of lower oscillations is accompanied by a loss of efficiency due to the change in operating parameters at the operating points if the initial operating map 1 is (pre)optimized for maximum efficiency. Then the operating points are only changed if the loss of efficiency is tolerated as measured by the choice of limit values. As a result, the change module 22, which can alternatively be referred to as an optimization module (optimization of NVH) and, as shown in FIG. 2, generates an operating map 3 optimized with regard to NVH. This optimized operating map 3 is generated by an output module 23 output, which, as an alternative to the representation of FIG. 2, can also be implemented together with the change module 22.

As can be seen by looking at FIGS. 1 and 2 together by an arrow between FIGS .a control unit. 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 3 compared to the initial operating map 1 are. On the other hand, outside of these local and critical NVH areas, the electric drive system can operate at maximum efficiency

11 can be worked on. 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 3 is then implemented in the motor vehicle 10 and used online, i.e. while the motor vehicle 10 is driving.

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.

In method step 31, the 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 established by the change module 22. Such a condition can in particular be that a torque and a speed of the at least one electric motor

12 are retained by the pre-optimized operating map 1. Further conditions can specify the maximum available voltage and a maximum permitted current as operating parameters of the electric motor 12.

Parallel to or, alternatively, before or after method steps 31 and 32, method steps 33, 34 and 35 are carried out one after the other. By In 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 method step 34, the force map 2 is then generated on the basis of an operating simulation of the simulation model of the electric motor 12 with the initial operating map 1. The force map 2 can represent the forces occurring in a time-space order. The force map 2 can be spanned over each operating point by current components Id, Iq of the current with force characteristics, for example in Newton. In method step 35, the force map 2 thus obtained is then made available for optimization.

In the method step 36, the optimization of the initial operating map 1 now takes place, whereby the operating points selected, as described above, in the initial operating map 1 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 3 is output for use in the electric drive system 11 of the motor vehicle 10.

The above explanations of the embodiments describe the present invention solely in terms of examples.

Reference symbol list

1 output operating map

2 force map

3 optimized operating map

10 motor vehicle

11 electric drive system

12 component, electric drive component, electric motor

13 component, electric drive component

20 system

21 Deployment Module

22 change module

23 output module

30 procedures

31-37 procedural steps

Claims

Patent claims

1 . Method (30) for reducing the audible and/or noticeable vibrations of an electric drive system (11) of a motor vehicle (10) by outputting an optimized operating map (3) for an electric motor (12) of the electric drive system (1 1), the method (30) is characterized by the following steps:

(a) providing an output operating map (1) of the electric motor (12), the output operating map (1) comprising operating points of the electric motor (12),

(b) providing a force map (2) of at least one component (12, 13) of the electric drive system (11) for the operation of the electric motor (12) with the provided output operating map (1), the force map (2) being in operation of the electric motor (12) on the at least one component (12, 13) of the electric drive system (1 1) for at least a partial range of operating points of the output operating map (1),

(c) changing operating points of the initial operating map (1) in at least one partial operating range of the initial operating map (1) based on the force map (2) provided to reduce the audible and/or noticeable vibrations in the at least one partial operating range, and

(d) Outputting the changed initial operating map (1) as an optimized operating map (3).

2. Method (30) according to claim 1, characterized in that the component (12, 13) of the electric drive system (1 1) is the electric motor (12) or a component of the electric motor (12).

3. Method (30) according to claim 1 or 2, characterized in that the method (30) is carried out outside the motor vehicle (10).

4. Method (30) according to one of the preceding claims, characterized in that the reduction of the audible and / or noticeable Oscillations in the at least one partial operating area are accompanied by a loss of efficiency in the at least one partial operating area. 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 range. Method (30) according to claim 5, characterized in that the at least one partial operating range is selected if it exceeds a predefined limit value of forces occurring and / or falls below a predefined limit value of a loss of efficiency. Method (30) according to one of the preceding claims, characterized in that the initial operating map (1) is or will be optimized for maximum efficiency of the electric drive system (11) outside the at least one partial operating range. Method (30) according to one of the preceding claims, characterized in that step (c) is carried out under the condition that a torque and a speed of the electric motor (12) are maintained from the output operating map (1). Method (30) according to one of the preceding claims, characterized in that in step (c) at least one operating parameter or several operating parameters of the electric motor (12) are changed. Method (30) according to claim 9, characterized in that the at least one operating parameter is a voltage and/or a current intensity of the electric motor (12). Method (30) according to one of the preceding claims, characterized in that the method (30) further comprises generating the force map (2) based on a simulation model of the at least one component (12, 13) of the electric drive system (11). Method (30) according to claim 11, characterized in that the generation of the force map is based on a finite element analysis.

13. Use of an optimized operating map (3) output by the method (30) according to one of the preceding claims for controlling the operation of an electric motor (12) of an electric drive system (1 1) of a motor vehicle (10).

14. System (20) for reducing the audible and / or noticeable vibrations of an electric drive system (11) of a motor vehicle (10), the system being characterized by:

- a provision module (21) for

- a change module (22) for

- an output module (23) for

15. Computer program product, comprising commands which, when the program is executed by a computer, cause it to use the method (30) according to one of claims 1 to 12 or the use according to claim 13 to carry out.