DE102021207598A1 - Procedure for determining the consumption of an electric drive motor and test bench - Google Patents

Abstract

The invention relates to a method for determining the consumption of an electric drive motor, which comprises the following steps:
- Determination of three or more map points with the highest energy density,
- Creation of triangles, which enclose the map points with the highest energy density,
- Generation of a triangular network from the 15 working points, with the 15 working points being used as interpolation points for interpolating a loss index,
- Interpolation of the power loss based on the triangular network and calculation of consumption of the electric drive motor,
- Approval of the electric drive motor for installation in a motor vehicle if the
calculated usage is less than a usage threshold.
The invention also relates to a test stand for carrying out such a method.

Description

The invention relates to a method for determining the consumption of an electric drive motor for a motor vehicle and a test stand for carrying out such a method according to the preamble of the independent patent claims.

In the production of electric drive motors, there is a certain series variation due to physical component properties. This scattering of the component properties, for example the scattering of the ohmic resistance, or tolerance chains of the components due to the manufacturing accuracy, have an impact on the scattering of the electrical power loss of the electric drive motor. Due to the legislation for determining a standard consumption, it is necessary to know this scatter band in order to be able to derive a correct standard consumption for the drive motors of a series.

It is known from the prior art to carry out a detailed map measurement of an electric drive on a drive test bench. Such a measurement provides very precise information about the characteristics of an electric drive, but is associated with a great deal of effort. A component consumption value for measuring the standard consumption can be determined on the basis of the map measurement and the operating points relevant to the standard consumption. Repeating this measurement procedure for several drives produces the scatter band we are looking for.

Since such an individual measurement can take up to a week on the test stand, the time required to carry out such a measurement was not transferred to series production. In addition, the lot size for determining the scatter band should be as large as possible in order to evaluate a representative sample and to ensure the best possible statistical security. The more precisely the scatter band is known, the more precisely the standard consumption, for example the WLTP consumption, can be specified. The broader the scatter band in the loss index, the more statistical reserve must be maintained in the development in order to ensure that the official limit value for approval is observed for every drive. This leads to unnecessarily high development costs, which the improved interpolation method avoids.

In addition, the rejection of drives is directly dependent on the consumption forecast for the respective drive and the specified standard consumption. It is therefore desirable to determine a consumption index for each manufactured drive as precisely as possible.

With a more precisely determined loss index on the series test bench, fewer drives have to be sorted out and reworked in series production because they exceed the consumption value desired for approval.

From the DE 102 32 294 A1 a method for determining electrical losses in an electric drive motor is known. In this case, a voltage is applied to a coil winding at a first point in time. From this first point in time to a second point in time, the current flowing through the coil winding and the voltage applied to the coil winding during this period are recorded. The electromagnetic losses are determined from the values obtained.

the DE 10 2009 038 245 A1 discloses a method for evaluating an electric traction motor that includes a rotor with a plurality of magnets mounted thereon and a stator with a plurality of windings located near the rotor and coupled to an inverter. It is provided that the electric drive motor is rotated in such a way that a voltage is induced in the windings of the stator and the inverter. This voltage is measured at the inverter, with the voltage constant of the electric drive motor being calculated from the measured voltage. This voltage constant is compared to accepted voltage constants, identifying the electric drive motor as unacceptable if the voltage constant is outside the range of the accepted voltage constants.

From the DE 10 2017 007 422 A1 is a method for determining manufacturing tolerances of an electrical machine for a motor vehicle that has a stator and a rotor that can rotate relative to the stator. In doing so, the rotor is rotated relative to the stator and while the rotor rotates relative to the stator, an open circuit voltage is sensed in an inverter connected to the electric machine. In addition, the manufacturing tolerances when the electric machine is completely installed in the motor vehicle as a function of the detected no-load voltage and as a function of an at least short-circuit current flowing through the inverter, which is detected while the rotor rotates relative to the stator.

A disadvantage of the methods known from the prior art, however, is that the accuracy of the interpolation method is not high enough to use the loss index of the electric drive motors in a series final test (end-of-line test) as a measure of the power consumption relevant to approval for electric drive motors to be determined with a high level of statistical certainty. By using the more precise interpolation method described here, fewer drives have to be sorted out and reworked, since the loss index is now determined with greater statistical certainty.

The invention is now based on the object of carrying out a consumption measurement of an electric drive motor, which can be carried out quickly and with little effort and has a higher level of accuracy for determining the consumption index using an improved interpolation method. This takes into account the comparatively short cycle times on the line for series production.

• - Ermitteln von drei oder mehr Kennfeldpunkten, vorzugsweise von vier Kennfeldpunkten, mit der höchsten Energiedichte,
• - Erzeugen von Dreiecken, vorzugsweise gleichseitigen Dreiecken, welche die Kennfeldpunkte mit der höchsten Energiedichte umschließen,
• - Messen von verschiedenen Arbeitspunkten des elektrischen Antriebsmotors, wobei eine erste Gruppe von Arbeitspunkten durch einen Testzyklus definiert wird, und wobei die Eckpunkte der erzeugten Dreiecke eine zweite Gruppe von Arbeitspunkten definieren,
• - Erzeugen eines Dreiecks-Netzes aus den Arbeitspunkten, wobei die gemessenen Arbeitspunkte als Stützstellen zur Interpolation der Verlustleitung an sämtlichen Arbeitspunkten des Testzyklus, insbesondere eines Verbrauchszyklus, genutzt werden,
• - Interpolation der Verlustleistung in den Arbeitspunkten (Stützstellen) aus dem kompletten Wirkungsgradkennfeld,
• - Interpolation der Verlustleistung auf Basis des Dreiecks-Netzwerkes und Berechnen eines Komponentenverbrauchs des elektrischen Antriebsmotors,
• - Freigabe des elektrischen Antriebsmotors zum Einbau in ein Kraftfahrzeug, wenn der mit dem Verfahren berechnete Komponentenverbrauch des elektrischen Antriebsmotors einen Grenzwert erreicht, der zum Einhalten des den Zulassungsbehörden nachzuweisenden Verbrauchs-Grenzwertes des Fahrzeugs führt.

This object is achieved by a method for determining the consumption of an electric drive motor, which includes the following steps:

• - Determining three or more map points, preferably four map points, with the highest energy density,
• - Generation of triangles, preferably equilateral triangles, which enclose the map points with the highest energy density,
• - Measuring different operating points of the electric drive motor, a first group of operating points being defined by a test cycle, and the corner points of the generated triangles defining a second group of operating points,
• - Generation of a triangular network from the operating points, with the measured operating points being used as reference points for interpolating the power loss at all operating points of the test cycle, in particular a consumption cycle,
• - Interpolation of the power loss in the operating points (interpolation points) from the complete efficiency map,
• - Interpolation of the power loss based on the triangular network and calculation of a component consumption of the electric drive motor,
• Approval of the electric drive motor for installation in a motor vehicle if the component consumption of the electric drive motor calculated using the method reaches a limit value which leads to compliance with the consumption limit value of the vehicle to be verified by the registration authorities.

In this context, the map points with the highest energy density are to be understood as meaning those map points which, when the map is subdivided into squares of equal size, represent a local maximum with regard to the power loss. The power loss normalized to a surface section of the map is therefore highest at these map points.

The proposed method makes it possible to make an accurate estimate of the energy consumption of an electric drive motor with a limited number of measurement points and to ensure that the electric drive motor meets its specification with regard to the maximum power consumption. In particular, the method makes it possible to determine a loss index during an end-of-line test, which is directly included in the vehicle's consumption limit to be achieved by the authorities, thus ensuring that the consumption values determined in a test cycle are statistically reliable for all those tested with this method Electric motors can be achieved.

Advantageous improvements and further developments of the method specified in the independent claim for determining the consumption of an electric drive motor are possible as a result of the features listed in the dependent claims.

In a preferred embodiment of the invention, it is provided that all generator working points are mirrored on the speed axis and a calculation of the consumption of the electrical Drive motor exclusively by operating points in the first quadrant of the map, ie in the motor drive area of the electric drive motor. Since both motor working points of the electric drive motor and generator working points of the electric drive motor are taken into account in a consumption cycle for motor vehicles with an electric drive motor, mirroring the working points leads to a simplified calculation of the consumption and thus to time savings in a series test.

In an advantageous embodiment of the method, it is provided that at least fifteen operating points of the electric drive motor are measured. In order to be able to make a statement relevant to the consumption and to be able to keep this within narrow tolerance ranges, the use of at least fifteen support points has proven to be particularly advantageous, since the four largest energy centers can thus be included in the interpolation. New interpolation points are defined by the corner points of the triangles around the four map points with the highest energy density and three further working points by edge points of the WLTP map. As a result, a particularly fast and precise interpolation between the individual working points and thus an exact prediction of the power consumption of the electric drive motor is possible.

In this case, it is preferred if three operating points of the first group of operating points span a right-angled triangle which delimits the test area and the operating points of the second group of operating points lie within this right-angled triangle. As a result, the characteristics map can be subdivided into triangles in a simple manner, which, within the framework of an interpolation, enable an exact prediction of the power loss and, associated therewith, of the power consumption of the electric drive motor.

It is particularly preferred if a square is formed from the three working points of the first group of working points and one working point from the second group of working points, this square being divided into two triangles by a diagonal. As a result, the map points of the highest energy density can be weighted correspondingly heavily during the interpolation, as a result of which a further improvement in the accuracy in the calculation of the power consumption of the electric drive motor is possible. The smaller equilateral triangles around the four largest energy centers interpolate comparatively more precisely in the areas of high power loss, which additionally increases the interpolation accuracy.

According to a particularly preferred embodiment of the method, it is provided that when calculating the power loss of the electric drive motor, the four map points with the highest energy density are taken into account. When measuring different types of electric motors, it turned out that there are usually four characteristic areas with high power loss in the efficiency map, which are used to increase the interpolation accuracy. As a result, a particularly precise prediction of the energy consumption of the electric drive motor is possible by determining these four characteristic map points.

In a further preferred embodiment of the invention it is provided that the triangles which enclose the points of the highest energy density are numbered consecutively according to the size of the energy density and these are weighted according to their energy density.

In an advantageous embodiment of the method, it is provided that a total of exactly 15 operating points are measured. The twelve corner points of the four triangles around the four map points with the highest energy density and three other operating points that delimit the map are preferably measured.

In an advantageous embodiment of the method, it is provided that the characteristic map is delimited by a line with the same power loss. If the map is delimited by a line of the same power loss, in particular by a line with a power loss of 4 kW, then all operating points of the WLTP consumption cycle lie within this map. As a result, the calculation of the power loss can be limited to this map area, so that the operating points within this map area can be used to estimate the power loss and thus the consumption of the electric drive motor very precisely.

A further partial aspect of the invention relates to a test bench for carrying out a determination of the consumption of an electric drive motor (end of line test bench), the test bench including a controller device which is set up to carry out such a method when a machine-readable program code is executed by the control device. With such a test stand, a sufficiently precise determination of the consumption of each individual electric drive motor produced before installation in a motor vehicle is possible with suitable calibrated measurement technology during production. In this way, the consumption of the electric drive motors can be checked using comparatively simple means and within a reasonable time interval. Such a test bench and such a test method are therefore particularly suitable for testing in series production of electric motors before the corresponding electric drive motor is installed in a motor vehicle.

• 1 ein Verlustleistungskennfeld eines elektrischen Antriebsmotors in welchem motorische und generatorische Arbeitspunkte im Rahmen eins WLTP-Verbrauchszyklus eingezeichnet sind.
• 2 ein aus dem Stand der Technik bekanntes Kennfelddiagramm eines elektrischen Antriebsmotors, in welchem acht stationäre Arbeitspunkte eingezeichnet sind.
• 3 ein Drehmoment-Drehzahl Kennfeld zur Ermittlung der Kennfeldpunkte der höchsten Energiedichte; und
• 4 ein Drehmoment-Drehzahl-Kennfeld eines elektrischen Antriebsmotors, an dessen Beispiel die Durchführung eines erfindungsgemäßen Verfahrens zur Bestimmung des Verbrauchs eines elektrischen Antriebsmotors erklärt wird.

The invention is explained below in exemplary embodiments with reference to the associated drawings. Show it:

• 1 a power loss map of an electric drive motor in which motor and generator working points are drawn in as part of a WLTP consumption cycle.
• 2 a map diagram of an electric drive motor known from the prior art, in which eight stationary operating points are located.
• 3 a torque-speed map for determining the map points of the highest energy density; and
• 4 a torque/speed characteristic diagram of an electric drive motor, using the example of which the implementation of a method according to the invention for determining the consumption of an electric drive motor is explained.

1 shows a torque-speed map for determining the power loss at 1800 consumption-relevant map points as part of a WLTP consumption cycle. Lines of equal power loss are drawn in the map next to the operating points.

Since the measurement of 1800 operating points in a series-accompanying test or in a series test for acceptance of each individual electric drive motor would be too time-consuming, the consumption within the framework of a WLTP cycle is determined by the power loss at individually selected operating points (interpolation points) and an interpolation between these operating points definitely.

In 2 a map diagram of an electric drive motor known from the prior art is shown, in which eight stationary operating points AP1, AP2, AP3, AP4, AP5, AP6, AP7 and AP8 for determining the power loss Pv in a method according to the invention are drawn.

Power losses for eight different stationary operating points AP1, AP2, AP3, AP4, AP5, AP6, AP7 and AP8 are used as input data for the calculation algorithm. These operating points AP1, AP2, AP3, AP4, AP5, AP6, AP7 and AP8 are defined in Table 1 below (a positive torque describes motor operation; a negative torque describes generator operation of the electric drive motor) and serve as setpoint specifications: Stationary operating point number Speed n of the electric drive motor Electric drive motor torque 1 0 0 2 4620 -160 3 4620 310 4 15750 75 5 50 110 6 2500 100 7 10500 30 8th 14000 0

The power loss Pv must be determined at the specified operating points AP. To do this, the following values are measured at axle level for each of the working points AP1 - AP8 specified in the table: - Axle speed left n _axis1 [1/s] - Axle speed right n _axis2 [1/s] - Axle moment on the left M _axis1 [Nm] - Axle moment right M _axis2 [Nm] - DC current I _DC [A] - DC voltage U _DC [V] - Stator temperature of electric drive motor TE [°C]

The measured values are then calculated for each of the stationary operating points AP1 - AP8 given in the table for the power loss Pv. $$\text{pv}={\text{u}}_{\text{DC}}*{\text{I}}_{\text{DC}}-2\mathrm{\Pi \ast }{\text{n}}_{\text{axis2}}*{\text{M}}_{\text{axis2}}$$

Each sensor is calibrated in the relevant value range, on the basis of which the measurement uncertainty of each individual sensor can be determined for the respective operating point AP1 - AP8. Furthermore, the measurement uncertainties determined are offset against partial performance uncertainties, taking into account the respective operating point AP1 - AP8. Based on the calculation of the power loss and its partial derivation, this results in a total of six partial power uncertainties for each operating point AP1 - AP8. In the case of an asymmetric uncertainty distribution, the partial power uncertainties for the positive and negative uncertainty must be calculated separately.

According to Gauss' law of error propagation, the six determined partial power uncertainties become a total measurement uncertainty for each of the operating points listed in the table.

According to this method, the result is a power loss P _V1 to P _V8 and its power loss uncertainty for each of the eight operating points AP1 to AP8 listed in the table.

On the basis of the determined power losses and their power loss uncertainties for the stationary operating points AP1 - AP8 listed in the table, the consumption index VI can be calculated as described below.

The calculation algorithm is based on a 2-dimensional level interpolation, which must be carried out for each test point CP of the reference cycle. Each cycle operating point CP _i is now assigned three operating points (AP _i , AP _j , AP _k ) in a data matrix, which can span an interpolation triangle containing CPi (see Fig 1 ).

In addition, two weighting factors k1, k2 are specified in the data matrix, which indicate the position of the test point CPi within the triangle formed from AP _i , AP _j and AP _k . First, the previously determined power loss P _Vi , P _Vj , P _Vk is assigned to the steady-state operating points AP _i , AP _j and AP _k . This results in three power loss values P _Vi , P _Vj , P _Vk at the corners of the triangle spanned by the stationary operating points AP _i , AP _j and AP _k .

The interpolated power loss value sought for the respective test point CPi can be calculated from these values using the weighting factors k1, k2. $$\text{pv}\left({\text{CP}}_{\text{i}}\right)=\text{pv}\left({\text{AP}}_{\text{j}}\right)+\text{k1}\left({\text{CP}}_{\text{i}}\right)*\left[\text{pv}\left({\text{AP}}_{\text{j}}\right)-\text{pv}\left({\text{AP}}_{\text{j}}\right)\right]+\text{k2}\left({\text{CP}}_{\text{i}}\right)*\left[\text{pv}\left({\text{AP}}_{\text{k}}\right)-\text{pv}\left({\text{AP}}_{\text{j}}\right)\right]$$

The time grid on which the data matrix is based is preferably based on a frequency of 1 Hz, so the determined power loss in the test point CP _i approximately corresponds to the energy throughput in this test point CP of the reference cycle RZ.

Finally, the consumption index VI is formed via a summation and normalization according to the following equation: $$VI=\frac{1WH}{23.27km\ast 3600Ws}\ast {\displaystyle \int {}_{CPi=0}^{1800}VL\left(CPi\right)}$$

The consumption index VI is calculated on the basis of a reference cycle, preferably on the basis of the WLTP and a reference vehicle. Based on this premise, the result of a vehicle measurement or longitudinal dynamics simulation is a load collective that describes the test points CP occurring in the reference cycle. The weighting factors k1 and k2 can be clearly determined in advance for each test point using the test points CP that occur in the reference cycle for a reference vehicle and the selected stationary operating points AP.

When measuring different electric drive motors on the end-of-line test benches, the temperature of the electric motors will not always be the same during the measurement. However, the maximum consumption index value specified as a "special feature of the approval" on the ZSB drive drawing is required for a specific mean electric machine temperature T _{E mean spec} . Therefore, a temperature correction may be necessary, which is described below.

First, the average temperature of the electric drive motor is calculated using the stationary operating points AP1 - AP8 listed in the table. Furthermore, based on the specific mean electric machine temperature T _{E mean spec} , an expected value for the consumption index VI can be derived for a different temperature.

In ongoing production, compliance with the "Special feature of the approval" with regard to the consumption index for the drives produced must be ensured. It is recommended to carry out an end-of-line measurement (EOL measurement) for each drive produced with the eight stationary operating points AP1 - AP8 listed in the table and to determine a consumption index value VI. Knowing the associated temperature T _{E mean} act, a consumption value VI _T,cor temperature-corrected to 40° C. can be determined. $${\text{VI}}_{\text{T}\text{,cor}}=\text{VI}+\Delta \text{VI}$$

On the basis of the temperature-corrected consumption index VI _T,kor , it is recommended that continuous statistics be generated for all electric drive motors produced. In addition, the temperature dependency of the consumption index VI can be viewed and evaluated using the consumption index VI and the associated temperature T _{E mean actual} in ongoing production.

The consumption index VI is calculated on the basis of a reference cycle, preferably on the basis of the WLTP and a reference vehicle. Based on this premise, the result of a vehicle measurement or longitudinal dynamics simulation is a load collective that describes the test points CP occurring in the reference cycle. The weighting factors k1 and k2 can be clearly determined in advance for each test point using the test points CP that occur in the reference cycle for a reference vehicle and the selected stationary operating points AP.

When measuring different electric drive motors on the end-of-line test benches, the temperature of the electric motors will not always be the same during the measurement. However, the max. consumption index value specified as a "special feature of the approval" on the ZSB drive drawing is required for a specific mean electric machine temperature TE _{mean spec} . Therefore, a temperature correction may be necessary, which is described below.

First, the average temperature of the electric drive motor is calculated using the stationary operating points AP1 - AP8 listed in the table. Furthermore, based on the specific mean electric machine temperature TE _{mean spec} , an expected value for the consumption index VI can be derived for a different temperature.

In ongoing production, compliance with the "Special feature of the approval" with regard to the consumption index for the drives produced must be ensured. It is recommended to carry out an EOL measurement for each drive produced using the eight stationary operating points AP1 - AP8 listed in the table ren and to determine a consumption index value VI. With knowledge of the associated temperature TE average, a consumption value VIT, cor that has been temperature-corrected to 40° C. can be determined. $$\text{VI T}\text{,cor}=\text{VI}+\Delta \text{VI}$$

Based on the temperature-corrected consumption index VI T, kor it is recommended to create continuous statistics for all electric drive motors produced. In addition, the temperature dependency of the consumption index VI can be viewed and evaluated using the consumption index VI and the associated temperature T _{E mean actual} in ongoing production.

In 3 a torque-speed characteristic diagram of an electric drive motor is shown, in which the areas of the highest energy density and the associated highest power loss are drawn. The map is searched for the points of highest energy density and corresponding points are marked. in the in 3 In the illustrated embodiment, the four points of the highest energy density KP _{EDmax are numbered} from 1 to 4 without weighting these points according to their power loss. The map is set using an in 3 Completely meander through the search quadrant shown from top to bottom. For a momentarily fixed point (M _i ; n _j ) as the center of the search quadrant, all the power losses P _{V (M,n)} that are in this fixed search quadrant are summed up. The total value is normalized to the area of the search quadrant. The search square is then shifted one step further and the process described is repeated until the entire map has been traversed. An energy density distribution is thus obtained for the efficiency map and the map points with the greatest energy density can be read using the i×j search quadrants and the power loss in the respective search quadrant. The corresponding values of the energy densities of the search quadrants can be sorted in descending order using a simple spreadsheet program.

Disadvantageous with the in 2 However, due to the selection of the eight operating points and an insufficient number of operating points, relatively large inaccuracies still occur when determining the loss index.

To calculate the loss index VI according to the method according to the invention, only the four points of the greatest energy density that are within a measurement cycle, in particular within the WLTP cycle, are considered for the interpolation points from the efficiency map.

• - Ermitteln von drei oder mehr Kennfeldpunkten mit der höchsten Energiedichte,
• - Erzeugen von Dreiecken, welche die Kennfeldpunkte mit der höchsten Energiedichte umschließen,
• - Messen von verschiedenen Arbeitspunkten des elektrischen Antriebsmotors, wobei eine erste Gruppe von Arbeitspunkten durch einen Testzyklus definiert wird, und wobei die Eckpunkte der erzeugten Dreiecke eine zweite Gruppe von Arbeitspunkten definieren,
• - Erzeugen eines Dreiecks-Netzes aus den Arbeitspunkten,
• - Interpolation der Verlustleistung auf Basis des Dreiecks-Netzwerkes und Berechnen eines Verbrauchs des elektrischen Antriebsmotors,
• - Freigabe des elektrischen Antriebsmotors zum Einbau in ein Kraftfahrzeug, wenn der berechnete Verbrauch kleiner ist als ein Schwellenwert für den Verbrauch.

In 4 a torque/speed characteristic diagram of an electric drive motor is shown, using the example of which the implementation of a method according to the invention for determining the consumption of an electric drive motor is explained. The procedure comprises at least the following steps:

• - Determination of three or more map points with the highest energy density,
• - Creation of triangles, which enclose the map points with the highest energy density,
• - Measuring different operating points of the electric drive motor, a first group of operating points being defined by a test cycle, and the corner points of the generated triangles defining a second group of operating points,
• - Creation of a triangular mesh from the working points,
• - Interpolation of the power loss based on the triangular network and calculation of consumption of the electric drive motor,
• - Release of the electric drive motor for installation in a motor vehicle if the calculated consumption is less than a threshold value for consumption.

In a first process step, as in 3 Four map points KP _EDmax with the highest energy density are shown. The generator measuring points of the WLTP cycle in the fourth quadrant of the map, i.e. in the generator working range of the electric drive motor, are mirrored in the first quadrant, i.e. in the area of the electric drive. The map is limited by the working points AP1, AP5 and AP8. The operating point AP5 is shifted vertically along the torque axis up to the characteristic with 4KW power loss so that all operating points of the WLTP cycle are within this map. The operating point AP8 is shifted horizontally along the speed axis up to the characteristic with 4KW power loss. In a subsequent method step, equilateral triangles are preferably formed around the four map points of the highest energy density. This creates the working points AP2 - AP4, AP6, AP7 and AP9 to AP15 at the corners of the triangles. To calculate the power loss, the corners of the four triangles are each connected to the operating points AP1, AP5 and AP8, which delimit the map. The resulting squares are each divided by a diagonal into two new triangles. The four triangles around the map points with the highest energy density KP _EDmax are numbered 1 to 4 according to the energy density, beginning with the triangle which encloses the map point with the highest energy density. Then it becomes 2 described interpolation method for the spanned from the 15 working points AP1 to AP15 triangular network applied, beginning with the triangles, which include the corner points around the map point 1 with the highest energy density. The interpolation process is then continued with the corner points of the triangles which enclose map points 2 to 4. Interpolation points from the WLTP test cycle, which were already calculated when calculating the triangular network around map point 1, can be disregarded when calculating the triangular network around map points 2, 3 and 4 in order to weight the map points with the highest energy density accordingly and to further increase the accuracy of the process.

Reference List

AP

operating point

AP1

Operating point from a first group of operating points

AP2

Operating point from a second group of operating points

APEA

Operating point in motor operation

APgen

Operating point for generator operation

CP

checkpoint

KPEDmax

Map point with maximum energy density

Nm

Newton meter

pv

dissipation

RZ

reference cycle

S

Threshold for maximum allowable consumption

Stray

Threshold for maximum allowable variation

T [Nm]

Torque (in Newton meters)

T

temperature

tom

medium temperature

VI

consumption index

k1

first weighting factor

k2

second weighting factor

n

rotational speed

rpm

revolutions per minute

QUOTES INCLUDED IN DESCRIPTION

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

Patent Literature Cited

• DE 10232294 A1 [0007]
• DE 102009038245 A1 [0008]
• DE 102017007422 A1 [0009]

Claims (10)

Method for determining the consumption of an electric drive motor, comprising the following steps: - determining three or more map points (KP _EDmax ) with the highest energy density, - generating triangles which enclose the map points (KP _EDmax ) with the highest energy density, - measuring different operating points (AP) of the electric drive motor, with a first group of operating points (AP1) being defined by a test cycle, and with the corner points of the generated triangles defining a second group (AP2) of operating points, - generating a triangular network from the operating points (AP), - Interpolation of the power loss (Pv) based on the triangular network and calculation of a consumption of the electric drive motor, and - Approval of the electric drive motor for installation in a motor vehicle if the calculated consumption is less than a threshold value for consumption. procedure after claim 1 , wherein generator working points (AP _gen ) are mirrored on the X-axis and the consumption of the electric drive motor is calculated exclusively by working points (AP) in the motor drive area of the electric drive motor. procedure after claim 1 or 2 , whereby at least 15 operating points (AP) of the electric drive motor are measured. procedure after claim 3 , characterized in that three operating points (AP) of the first group of operating points (AP1) span a right-angled triangle which delimits the test area and the operating points of the second group of operating points (AP2) lie within this right-angled triangle. procedure after claim 4 , characterized in that a square is formed from the three working points of the first group of working points (AP1) and one of the working points from the second group of working points (AP2), this square being divided into two triangles by a diagonal. Method according to claim one of Claims 1 until 5 , where the triangles that enclose the points (KP _EDmax ) of the highest energy density are numbered according to the size of the energy density and these are weighted according to their energy density. Procedure according to one of Claims 1 until 6 , characterized in that when calculating the power loss (P _V ) of the electric drive motor, the four map points (KP _EDmax ) with the highest energy density are taken into account. Procedure according to one of Claims 1 until 7 , characterized in that a total of exactly 15 operating points (AP) are measured. Procedure according to one of Claims 1 until 8th , characterized in that the map is limited by a line of equal power loss. Test stand for carrying out a consumption determination of an electric drive motor with suitable measurement technology, the test stand having a control device which is set up to carry out a method according to one of Claims 1 until 9 to be carried out when a machine-readable program code is executed by the control device.

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