DE102013018934A1 - Method for operating e.g. permanent magnet-excited synchronous motor for driving auxiliary transmission oil pump in vehicle, involves determining starting voltage and/or operating cycle for starting motor based on current and resistance - Google Patents

Abstract

The method involves switching-off a sensorless electric motor (2), and providing predetermined motor voltage (Um) to a stator (2.1) of the electric motor after a predetermined time period and after switching-off the electric motor. Actual motor current (Im) is measured, and actual motor resistance (R) of the electric motor is determined. Starting voltage (Us) and/or starting operating cycle (Cs) for starting the electric motor is determined or adapted and stored during future restart based on the measured motor current and the determined motor resistance. An independent claim is also included for a device for operating a sensorless electric motor for driving a transmission oil pump.

Description

The invention relates to a method for operating a sensorless electric motor for driving a transmission oil pump of an automatic transmission of a vehicle. Moreover, the invention relates to a device for operating a sensorless electric motor.

An electric motor in the transmission oil for driving a transmission oil pump is warmed up by the transmission oil and by its own power loss. As a result, the motor resistance of the electric motor changes.

From the DE 10 2005 051 884 A1 It is known to determine various engine characteristics during operation of the electric motor.

The invention has for its object to provide an improved, in particular the switch-shortening shortening process for operating a sensorless electric motor for driving a transmission oil pump of an automatic transmission of a vehicle. In addition, a suitable device for operating a sensorless electric motor is to be specified.

The object with regard to the method is achieved by the features of claim 1. With regard to the device, the object is achieved by the features of claim 8.

Advantageous developments of the invention are the subject of the dependent claims.

In the method for operating a sensorless electric motor for driving a transmission oil pump of a vehicle, the electric motor is switched off, wherein after a predetermined period after switching off the electric motor, a stator of the electric motor is acted upon by a predetermined motor voltage and a resulting current motor current and a current motor resistance of the electric motor are determined, based on the determined current engine resistance and the measured current motor current, a starting voltage and / or a start operating cycle for starting the electric motor in a future restart determined and / or adjusted and stored.

In other words, the invention enables a pre-setting of the optimum starting voltage and / or the optimal starting operating cycle (also called start-duty-cycle), in particular for setting and / or adjusting the starting operating cycle component tolerances and a temperature dependence of the electric motor or its components before a next restart of the electric motor and the pump. Thus, temperature-dependent component tolerances are automatically taken into account and the sensorless startup can be done with optimal parameters and parameters. As a result, start-up currents are reduced and an overload is prevented, whereby the components are protected and a lifetime of the components can be effected. The starting voltage and / or the starting operating cycle may be continuously adapted to hardware tolerances during the life of the electric motor. In addition, a complex determination of start characteristics during a start of the electric motor is reliably avoided. The determined current motor resistance is always present and no complex simulation model needs to be created.

Depending on the presence of already stored temperature- and / or pressure-dependent parameters and / or maps for a restart or start-up of the electric motor are determined as starting voltage and / or start operating cycle, a current starting voltage and / or a current start operating cycle and / or a stored starting voltage and / or adapted a stored starting operating cycle. Thus, a continuous adaptation of the starting characteristics, such as starting voltage and starting operating cycle, to currently detected characteristics, such as currently determined motor resistance and currently measured motor current, allows.

Shutdown of the electric motor is understood to mean, in particular, such an operating state of the electric motor in which it is inactive and is not permanently speed-controlled or current-controlled.

Under motor voltage is understood in particular the voltage applied to the electric motor and thus a voltage applied to an output of a power electronics voltage. Alternatively, a supply voltage, in particular a battery voltage, can be understood as voltage magnitude.

The motor resistance of the electric motor is in particular its system resistance, which comprises, for example, an internal electrical resistance and at least one contact resistance. The motor resistance is determined on the basis of the applied motor voltage and the motor current flowing through it.

The advantage of the invention is that the switch-on of the transmission oil pump, such as an additional transmission oil pump is reduced, since the start operating cycle and / or the starting voltage at the next restart of the electric motor optimally adjusted by the current engine resistance and optionally reduced or is. This will be on the one hand prevents overload and on the other spared the electronic components and causes a lifespan increase.

In a further development of the invention, the electric motor is energized after the predetermined period of time after its shutdown with a predetermined motor current to be placed in a predetermined starting position. Here, the electric motor is energized with a predetermined motor current such that the rotor is moved in a predetermined direction to the predetermined starting position, in particular by means of magnetic force is pulled.

In addition, after the position of the electric motor in the predetermined starting position of the stator is applied to the predetermined motor voltage, wherein the current motor current and the current motor resistance for determining or adaptation of the starting voltage and / or the starting operating cycle are determined for the next start. Thus, the next cycle start cycle is further optimized by eliminating pre-positioning during startup and determining and adjusting the starting voltage or start cycle for the onset starting position based on the current and temperature-dependent engine resistance and / or current engine current.

For a continuous adjustment and optimization of the start-up or start of the electric motor is after each shutdown of the electric motor, this newly positioned in the predetermined starting position and acted upon by the predetermined motor voltage, the current motor current measured and the current motor resistance is determined and stored.

To initialize the operation of the electric motor, the predetermined motor voltage is determined based on a stored temperature-dependent motor resistance and a stored temperature-dependent motor current before a first restart. In particular, the motor voltage to be applied is determined on the basis of, for example, a temperature of 20 ° C stored engine resistance and stored motor current. For this purpose, in particular maps applicable to both the motor resistance and the motor current, in particular temperature-dependent and / or pressure-dependent maps, are stored.

For the subsequent starts during operation of an automatic start-stop system, the voltage which results from the determination of the stored actual motor resistance and the stored current motor current as a result of the application of the electric motor with the predetermined motor voltage for the first restart or of a subsequent restart. In this case, in particular an average current engine resistance is determined and stored as the current engine resistance, which is determined on the basis of a plurality of engine resistance values determined during the application of the predetermined engine voltage to the electric motor. Likewise, an average current motor current is determined and stored based on a plurality of motor current values determined during application of the predetermined motor voltage to the electric motor.

In addition, this is switched to the deactivation of the electric motor in an inactive state. To safely cause the rotor to run out and thus to shut down the electric motor before determining relevant startup parameters or startup parameters, the required parameters such as motor voltage, motor current and motor resistance are only determined after a predetermined period of time has elapsed after the electric motor has been switched off, in particular newly determined or adjusted for a subsequent restart or startup. In other words, it is given such a period of time and waits, which ensures that the rotor of the electric motor has leaked and stands still.

The electric motor is permanently powered by a power supply. In this case, the power supply of the electric motor consists for example of a high-voltage supply (also called HV supply), in particular a 48 V supply, and a low-voltage supply, in particular a 12 V supply.

With regard to the device for operating a sensorless electric motor for driving a transmission oil pump of an automatic transmission of a vehicle with an electric motor as a drive of the transmission oil pump and a power electronics associated power electronics, the object is achieved in that a starter unit is provided and set up such that it shuts off the electric motor and after a predetermined period of time has elapsed after the electric motor has been switched off, a stator of the electric motor is subjected to a predetermined motor voltage, a resulting current motor current and a current motor resistance of the electric motor being ascertainable, and wherein a starting voltage and / or a start operating cycle for starting the electric motor in a future restart and / or start can be determined and / or adjusted.

One possible embodiment provides that by means of the starter unit a current Start voltage and / or a current start operating cycle determined and / or a stored start voltage and / or a stored start operating cycle can be adjusted.

In one possible embodiment, the starter unit is implemented in a transmission and / or engine control and set up such that by means of this the electric motor can be switched into an inactive state. The inactive state of the electric motor, in which this is not in an operative operating state and is not regulated in power or speed, is understood in particular as a shutdown of the electric motor. The starter unit is designed in particular as a software module.

In addition, the starter unit is set up in such a way that by means of this, after the electric motor has been switched off and a predetermined time has elapsed, the stator of the electric motor can be acted upon by a predetermined voltage value for the motor voltage.

Embodiments of the invention will be explained in more detail below with reference to a drawing.

Showing:

1 schematically an embodiment of a structure of a device according to the invention for operating a sensorless electric motor.

The only 1 schematically shows an embodiment of a structure of a device according to the invention 1 for operating an electric motor 2 for driving a transmission oil pump 3 , such as an auxiliary transmission oil pump of a two-pump system, an automatic transmission of a vehicle.

The electric motor 2 is a sensorless electric motor and serves, for example, as the main drive of the transmission oil pump 3 , in particular the additional transmission oil pump. The electric motor 2 is a synchronous motor, in particular a permanent magnet synchronous motor. The electric motor 2 includes a stator 2.1 and a rotor 2.2 ,

To operate the electric motor 2 includes the device 1 a the electric motor 2 associated power electronics 4 or commutation unit. The electric motor 2 again drives in accordance with the power electronics 4 the transmission oil pump 3 at.

A battery 5 supplies the power electronics 4 of the electric motor 2 with current via a first line L1.

The transmission oil pump 3 is mechanical with a motor shaft 6 of the electric motor 2 couplable or connectable. The power electronics 4 supplies the electric motor 2 with power and controls and monitors its function via a second line L2.

In addition, the device includes 1 a starter unit 7 , which may be formed separately or integrated into an engine or transmission control unit. The starter unit 7 is provided and arranged such that these after switching off the electric motor 2 the rotor 2.2 of the electric motor 2 so repositioned or prepositioned that the rotor 2.2 and thus the motor shaft 6 a position in a predetermined starting position before a next restart or start of the electric motor 2 occupies.

For this purpose, the electric motor 2 with a predetermined motor current I _m so energized that the rotor 2.2 is moved or pulled in one direction until it reaches the predetermined start position.

Further, the starter unit 7 set up so that this after switching off the electric motor 2 and possibly repositioning the rotor 2.2 in the specified starting position the stator 2.1 with a predetermined voltage value for a motor voltage U _m acted upon.

The starter unit 7 For example, it is implemented in a transmission and / or engine control and configured such that by means of this the electric motor 2 can be switched to an inactive state and thus switched off within the meaning of the invention.

This is the starter unit 7 with the power electronics 4 connected via a third line L3. The starter unit switches 7 via the power electronics 4 the electric motor 2 first in the inactive state and thus switches it off. Then the starter unit controls 7 via the third line L3 the power electronics 4 such that the stator 2.1 of the electric motor 2 with a motor voltage U _m , in particular clocked, time and / or pulse-shaped, is applied.

The battery 5 also supplies the starter unit 7 and / or a higher-level transmission and / or motor control via a fourth line L4 with power.

In detail is the starter unit 7 set up such that by means of this after switching off the electric motor 2 the stator 2.1 with a predetermined voltage value for the motor voltage U _{m can be} acted upon.

The starter unit determines 7 after switching off the electric motor 2 (= inactive Electric motor) a resulting from the application of the motor voltage U _m current motor current I _m on the electric motor 2 , Based on the predetermined motor voltage U _m and the determined current motor current I _m is by means of the starter unit 7 then a current motor resistance R of the electric motor 2 determined.

Under the motor voltage U _m is in particular one at the output of the power electronics 4 Pending motor voltage, ie at the electric motor 2 applied voltage, understood.

Alternatively, a voltage derived from a current supply voltage or battery voltage can be used as the motor voltage U _m . For example, at a battery voltage of 12 V, the battery 5 As motor voltage U _m 50% of the battery voltage of 12 V and thus 6 V are used for charging.

Under the motor resistance R of the electric motor 2 In particular, the temperature-dependent resistance of the entire system (also called motor resistance R), ie at least the internal electrical resistance, at least one transition or terminal resistance between the power electronics 4 and the electric motor 2 and optionally further from the structure of the electric motor 2 resulting internal resistances and / or transition or connection resistances understood. The motor resistor R can be determined based on the applied instantaneous or actual motor voltage U _m and the resulting flowing instantaneous or actual motor current I _m .

For continuous adaptation and optimization of the startup or start of the electric motor 2 will be after each shutdown of the electric motor 2 this newly positioned in the predetermined starting position and applied to the predetermined motor voltage U _m , wherein measured after each shutdown of the current motor current I _m and the current motor resistance R is determined and stored and thus updated.

Based on the determined or stored current engine resistance R and / or the determined or stored current motor current I _m is then by means of the starter unit 7 a starting voltage U _S and / or a start operating cycle C _S for starting the electric motor 2 determined on a future or next reboot. Alternatively or additionally, a stored starting voltage U _S-1 , in particular a previously determined and stored starting voltage U _S-1 and / or a reference starting voltage U _Sref and / or a stored starting _{operating cycle} C _S-1 , in particular a previously determined and stored starting _{operating cycle} C _S-1 and / or a reference start _{operating cycle} C _Sref . This is a continuous resistance and / or temperature-dependent adjustment of the start or start of the electric motor 2 possible.

For example, the starting voltage U _{S is} determined by means of the determined current motor resistance R and / or the determined current motor current I _m on the basis of at least one stored temperature-dependent characteristic map.

The starting operating cycle C _S is determined on the basis of the determined current motor current I _m and the determined current motor resistance R as well as on the basis of the determined starting voltage U _S , which, for example, as a percentage of the current supply voltage of the battery 5 is determined.

The starting operating cycle C _S , in particular a starting time and clocking, can also be determined by means of the determined current starting voltage U _S and the determined current starting current I _S and the determined current motor resistance R on the basis of stored characteristic diagrams (eg temperature-resistance characteristic diagram, temperature Motor current characteristic map) can be determined. In this case, the starting current I _S can be stored as an applicable map.

The starting speed n _S is temperature and pressure-dependent and can be stored as a further temperature and pressure-dependent map for controlling the engine speed n _m during the start operating cycle C _S.

To initialize the operation of the electric motor 2 Before a first restart, the predetermined motor voltage U _{m is} determined on the basis of a temperature-dependent motor resistance R (T) stored, for example, for a temperature of 20 ° C., and a stored temperature-dependent motor current I _m (T). For this purpose, in particular for both the motor resistor R and for the motor current I _m applicable maps, in particular temperature-dependent and / or pressure-dependent maps, stored.

For the subsequent starts during the operation of a start-stop system of the electric motor 2 is the voltage to be applied as the next to be applied motor voltage U _m , resulting from the determination of the stored previous current motor resistance R and the stored previous current motor current I _m as a result of the application of the electric motor 2 with the given motor voltage U _m for the first restart or a previous restart results.

In this case, as the current engine resistance R in particular a mean current engine resistance is determined and stored, the basis of several, during the application of the electric motor 2 determined with the predetermined motor voltage U _m determined engine resistance values. Likewise, as the current motor current I _m, an average current motor current based on several, during the application of the electric motor 2 determined and stored with the predetermined motor voltage U _m determined motor current values.

For example, the electric motor 2 several milliseconds, in particular 125 ms applied to the predetermined motor voltage U _m , wherein every 5 ms a measurement of motor current I _m and motor resistance R is carried out, on the basis of which then determines a respective average and stored as the current motor current I _m or current motor resistance R.

In other words: During operation of the electric motor 2 becomes the electric motor 2 after each shutdown with the, determined from the preceding and stored engine parameters (previous current motor resistance and previous current motor current) motor voltage U _m for a predetermined period of for example a few milliseconds, in particular 125 ms, applied. During the application of the electric motor 2 With the predefined motor voltage U _m determined from the preceding motor parameters, the current motor current I _m and the current motor resistance R are redetermined for a subsequent restart and optionally re-stored if the newly determined values for the current motor current I _m and the current motor resistance R are not equal to the previous stored values for the current motor current I _m and the current motor resistance R for the previous restart.

On the basis of these newly determined values for the current motor current I _m and the current motor resistance R, the starting voltage U _S and / or the starting operating cycle C _{S are} subsequently determined anew for the subsequent restart. The newly determined values for the starting voltage U _S and / or the starting operating cycle C _S are then at the next restart of the electric motor 2 for automated starting of the electric motor 2 by means of appropriate control of the power electronics 4 through the starter unit 7 used.

Thus, a continuous adaptation and optimization of the starting cycle is possible, whereby an overload of the electric motor 2 prevented and its life can be extended.

LIST OF REFERENCE NUMBERS

1

contraption

2

electric motor

2.1

stator

2.2

rotor

3

Transmission oil pump

4

power electronics

5

battery

6

motor shaft

7

starter unit

C _S

Start operating cycle

C _S-1

stored start operating cycle

C _Sref

Reference start operating cycle

I _m

motor current

I _m (T)

Motor current for a temperature

I _S

starting current

L1 to L4

cables

n _m

Engine speed

n _s

Starting speed

R

motor resistance

R (T)

Motor resistor for a temperature

U _m

motor voltage

U _S

starting voltage

U _S-1

deposited starting voltage

U _Sref

Reference start voltage

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been 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.

Cited patent literature

• DE 102005051884 A1 [0003]

Claims (10)

Method for operating a sensorless electric motor ( 2 ) for driving a transmission oil pump ( 3 ) of an automatic transmission of a vehicle, characterized in that - the electric motor ( 2 ) is switched off and - after a predetermined period of time after switching off the electric motor ( 2 ) a stator ( 2.1 ) of the electric motor ( 2 ) is applied to a predetermined motor voltage (U _m ), wherein - a resulting current motor current (I _m ) measured and a current motor resistance (R) of the electric motor ( 2 ), and - based on the measured motor current (I _m ) and the determined current motor resistance (R), a starting voltage (U _S ) and / or a starting operating cycle (C _S ) for starting the electric motor ( 2 ) can be determined or adjusted and stored during a future restart. Method according to claim 1, characterized in that the electric motor ( 2 ) after the expiry of the predetermined period after switching off the electric motor ( 2 ) is energized with a predetermined motor current (I _m ) to be placed in a predetermined starting position. A method according to claim 2, characterized in that after the position of the electric motor ( 2 ) in the predetermined starting position of the stator ( 2.1 ) is applied to the predetermined motor voltage (U _m ) and the current motor current (I _m ) measured and the current motor resistance (R) are determined and stored. Method according to one of the preceding claims, characterized in that after each shutdown of the electric motor ( 2 ) This new positioned in the predetermined starting position and with the predetermined motor voltage (U _m ) is applied and measured the current motor current (I _m ) and the current motor resistance (R) are determined and stored. Method according to one of the preceding claims, characterized in that for the initialization of the operation of the electric motor ( 2 ) before a first restart, the predetermined motor voltage (U _m ) based on a stored temperature-dependent motor resistance (R (T)) and a stored temperature-dependent motor current (I _m (T)) is determined. Method according to one of the preceding claims, characterized in that during the operation of the electric motor ( 2 ) the predetermined motor voltage (U _m ) based on the stored current engine resistance (R) and the stored current motor current (I _m ) is determined. Method according to one of the preceding claims, characterized in that for switching off the electric motor ( 2 ) this is switched to an inactive state. Contraption ( 1 ) for operating a sensorless electric motor ( 2 ) for driving a transmission oil pump ( 3 ) of an automatic transmission of a vehicle, with an electric motor ( 2 ) as a drive of the transmission oil pump ( 3 ) and one the electric motor ( 2 ) associated power electronics ( 4 ), characterized in that - a starter unit ( 7 ) is provided and arranged such that this the electric motor ( 2 ) and - after a predetermined period of time after switching off the electric motor ( 2 ) a stator ( 2.1 ) of the electric motor ( 2 ) is applied to a predetermined motor voltage (U _m ), wherein - a resulting current motor current (I _m ) and a current motor resistance (R) of the electric motor ( 2 ) can be determined and stored, and - based on the determined current motor resistance (R) and the current motor current (I _m ), a starting voltage (U _S ) and / or a start operating cycle (C _S ) for starting the electric motor ( 2 ) are determined and / or adjusted in a future restart. Contraption ( 1 ) according to claim 8, characterized in that the starter unit ( 7 ) is implemented in a transmission and / or engine control and is arranged such that by means of this the electric motor ( 2 ) is switchable to an inactive state. Contraption ( 1 ) according to claim 8 or 9, characterized in that the starter unit ( 7 ) is arranged such that by means of this after switching off the electric motor ( 2 ) the stator ( 2.1 ) With a predetermined motor voltage (U _m ) can be acted upon.

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