DE102020003873A1 - Method for compensating for a deviation of an actual position from a target position of at least one sensor - Google Patents

Abstract

The invention relates to a method for compensating for a deviation of an actual position from a target position of at least one sensor (32) by means of which the rotational positions of a rotor (24) of a commutated electric motor (10) can be detected. At least one complete revolution of the rotor (24) is effected after the sensor (32) has been installed in its actual position. During the at least one complete rotation of the rotor (24), at least one rotational position of the rotor (24) occurring during the at least one complete rotation of the rotor (24) is detected by the sensor (32). During the at least one complete rotation of the rotor (24), at least one rotational position of the rotor (24) occurring during the at least one complete rotation of the rotor (24) is detected by means of a detection device (44) provided in addition to the sensor (32). A deviation of the rotational position detected by the sensor (32) from the rotational position detected by the detection device (44) resulting from the deviation of the actual position from the target position is determined.

Description

The invention relates to a method for compensating for a deviation of an actual position from a desired position of at least one sensor, by means of which rotational positions of a rotor of a commutated electric motor can be detected.

the EP 1 420 510 A1 a method for adjusting a sensor device for determining the rotational position of a rotor of an electronically commutated rotor can be seen as known. In addition, the DE 198 12 966 A1 a brushless direct current motor, with a pole wheel position encoder to detect the rotor position.

The object of the present invention is to create a method so that a commutated electric motor can be operated particularly advantageously.

This object is achieved by a method with the features of claim 1. Advantageous configurations with expedient developments of the invention are specified in the remaining claims.

In the method according to the invention for compensating for a deviation of an actual position from a target position of at least one sensor, by means of which rotational positions of a rotor of a commutated electric motor can be detected, at least one complete rotation of the rotor is effected after the sensor is installed in its actual position. This means that the rotor is rotated by at least 360 ° and thus completely rotated at least once after the sensor and preferably all relevant components of the electric motor, which is designed as a servomotor, for example, have been installed. With such an assembly of the electric motor, there are technical and therefore unavoidable mechanical tolerances, as a result of which the sensor, for example designed as a Hall sensor or at least or precisely one Hall sensor, is not in the desired or planned target position, but in that of it different actual position is installed. The assembly of the sensor is to be understood in particular to mean that the sensor is fixed at least indirectly, in particular directly, to a housing of the electric motor, the rotor being rotatable about an axis of rotation relative to the housing.

During the at least one complete revolution of the rotor, at least one rotational position of the rotor occurring during the at least one complete revolution of the rotor is detected by means of the sensor. This means that the rotor comes into the at least one rotational position, which is detected by means of the sensor, when the rotor is rotated.

In addition, in the method, at least one rotational position of the rotor occurring during the at least one complete revolution of the rotor is detected by means of a detection device provided in addition to the sensor and, for example, external to the sensor, in particular to the electric motor, while the at least one complete revolution of the rotor is effected or is carried out.

In the method, a deviation of the rotational position detected by means of the sensor from the rotational position detected by means of the detection device resulting from the deviation of the actual position from the target position is also determined. As a function of the determined deviation of the rotational positions, at least one correction value is determined and stored in a memory device of a commutation electronics, which is designed to commutate the electric motor, also referred to simply as a motor, as a function of the correction value.

The invention is based in particular on the following knowledge: If the sensor were installed in the target position, i.e. if the actual position corresponded to the target position of the sensor, the rotational position detected by the sensor would correspond to the rotational position detected by the detection device. In other words, the sensor and the detection device would then detect the same rotational position. However, since the actual position of the sensor deviates from the target position, during the at least one complete revolution the sensor detects a rotational position that deviates from the rotational position in which the rotor is actually located and which is detected by the detection device. On the basis of the correction value, for example, a respective rotary position that is detected by the sensor during operation of the electric motor can be corrected in such a way that, for example, the actual rotary position of the rotor is calculated from the rotary position detected by the sensor. In particular, the correction value can be used to correct a signal provided by the sensor, in particular an electrical signal, which characterizes a respective rotary position detected by the sensor during operation of the electric motor, so that a respective actual rotary position of the rotor is calculated as a function of the signal can. The electric motor can then be operated, in particular regulated, by means of the commutation electronics embodied, for example, as an electronic computing device on the basis of the calculated, actual rotational position lower power consumption of the electric motor can be realized. In addition, the electric motor can be operated, in particular regulated, on the basis of other control parameters, and excessive thermal loading of the electric motor can be avoided.

The deviation of the actual position from the target position is a positioning error, which means that the rotational position in which the rotor is actually located deviates from the rotational position that is detected by the sensor and reported to the commutation electronics designed as an electronic computing device will. The deviation of the rotational position detected by means of the sensor from the actual rotational position can be compensated for by means of the correction value, as a result of which the deviation of the actual position from the target position is also compensated. The determination of the deviation between the rotational positions is thus an at least indirect determination of the positioning error, in particular when the electric motor is in a mounted state.

It is conceivable that the sensor and the detection device detect several respective rotary positions during the at least one complete revolution of the rotor, so that several correction values are determined on the basis of respective deviations between the respective rotary positions and stored, for example, in the form of a correction value table. The motor can then be regulated particularly advantageously during its operation on the basis of the correction values. The sensor is preferably a physical component, on the basis of which the electric motor, designed for example as a brushless direct current motor, can be operated, in particular controlled or regulated. The preceding and following explanations can, however, also be applied without further ado to sensorless motors in which, for example, the sensor for detecting the rotational position of the rotor is implemented electronically.

Further advantages, features and details of the invention emerge from the following description of a preferred exemplary embodiment and with reference to the drawing. The features and combinations of features mentioned above in the description as well as the features and combinations of features mentioned below in the description of the figures and / or shown on their own in the figures can be used not only in the respectively specified combination, but also in other combinations or on their own, without the scope of the Invention to leave.

• 1 ausschnittsweise eine schematische Querschnittsansicht eines kommutierten Elektromotors; und
• 2 eine schematische Ansicht eines Ventiltriebs einer Verbrennungskraftmaschine, wobei der Ventiltrieb den Elektromotor umfasst, welcher als Stellmotor zum Einstellen einer Phasenlage einer Nockenwelle relativ zu einer Kurbelwelle der Verbrennungskraftmaschine verwendet wird.

The drawing shows in:

• 1 a fragmentary schematic cross-sectional view of a commutated electric motor; and
• 2 a schematic view of a valve drive of an internal combustion engine, the valve drive comprising the electric motor which is used as a servomotor for setting a phase position of a camshaft relative to a crankshaft of the internal combustion engine.

Identical or functionally identical elements are provided with the same reference symbols in the figures.

1 shows a fragmentary schematic cross-sectional view of a commutated electric motor 10 , which is also referred to simply as a motor. 2 shows a schematic representation of a valve train 12th an internal combustion engine also known as an internal combustion engine. The valve train 12th has at least one camshaft 14th on, by means of which gas exchange valves 16 the internal combustion engine can be operated. The internal combustion engine designed as a reciprocating piston machine has an output shaft designed as a crankshaft, of which the camshaft 14th , in particular mechanically, can be driven or is driven. Using a camshaft sensor 18th can respective rotational positions or rotational positions of the camshaft 14th are recorded. The camshaft 14th is a camshaft adjuster 20th assigned, by means of which the camshaft 14th can be rotated relative to the crankshaft, especially while the camshaft 14th is mechanically connected to the crankshaft and is driven by the crankshaft. By turning the camshaft 14th relative to the crankshaft is the camshaft 14th adjusted in their phase position relative to the crankshaft, thereby control times of the gas exchange valves 16 can be varied. The camshaft adjuster 20th includes the electric motor 10 which is used to drive the camshaft 14th to rotate relative to the crankshaft, hence the camshaft 14th to adjust their phase position relative to the crankshaft. The camshaft can 14th via a transmission 22nd of the camshaft adjuster 20th by means of the electric motor 10 driven and thus rotated relative to the crankshaft.

The electric motor 10 has a stator, not shown in the figures, and a rotor 24 on, which is an output shaft also known as a rotor shaft 26th having. The rotor 24 can be driven by the stator and thus - as in 1 by an arrow 28 is illustrated - rotatable about an axis of rotation relative to the stator. About the rotor 24 , especially via the output shaft 26th , the electric motor can 10 a torque to drive the camshaft 14th or to turn the camshaft 14th provide relative to the crankshaft. The rotor 24 also includes a sensor wheel 30th , which is explained in more detail below. Furthermore, the electric motor 10 several, in particular at least or exactly three sensors 32 which are designed, for example, as Hall sensors or each comprise at least or precisely one Hall sensor. Using the sensors 32 can determine the respective rotational positions of the rotor 24 are recorded. In other words, the rotor will 24 relative to the stator and thus, for example, relative to a housing of the electric motor 10 rotated, in particular at least once completely, the rotor comes in this at least one complete revolution 24 in several different rotary positions, which are determined by means of the sensors 32 can be recorded. The respective sensor 32 provides, for example, a signal, in particular an electrical signal, which the respective, by means of the respective sensor 32 detected rotary position of the rotor 24 characterized. The sensors 32 are at least indirectly, in particular directly, attached to said housing. The respective sensor 32 has an in 1 actual situation illustrated by solid lines. In 1 is a respective target position of the respective sensor by dashed lines 32 illustrated. It can be seen that the respective actual position deviates from the respective target position due to tolerances. Thus, by means of the sensor 32 detected and by the signal of the respective sensor 32 characterized rotary position of the rotor 24 from an actual rotational position of the rotor 24 differ. This deviation of the means of the sensor 32 detected rotary position from the actual rotary position of the rotor 24 thus results from the deviation of the actual position from the target position, also referred to as a positioning error.

The electric motor 10 is, for example, a brushless direct current motor, which has commutation electronics, also referred to simply as electronics. By means of the commutation electronics, the electric motor 10 , in particular electrically or electronically, commutated. For a time control or regulation of the commutation, the commutation electronics can use the respective sensor 32 detected rotational position of the rotor, also referred to as the rotor position 24 be used. Alternatively, it is conceivable that the respective rotary position can alternatively or additionally be achieved by measuring electrical parameters on coils of the electric motor 10 is determined.

In particular, by means of the respective sensor 32 such a rotational position of the rotor 24 at which there is a change of polarity or polarity. Such, by means of the respective sensor 32 Polarity changes measured or detected by detecting the respective rotational position lead, for example, to a change in a switching state of a bridge circuit, and consequently to a new switching state of the bridge circuit. However, since the actual position can now deviate from the setpoint position due to tolerances, the rotational position, for example, is determined by means of the sensor 32 is detected, not a rotational position at which there is a polarity change, but a different rotational position of the rotor shortly thereafter or shortly before it 24 .

The rotor 24 is for example, especially about the transmission 22nd , torque-transmitting with the camshaft 14th coupled. As long as the rotor, for example 24 is not driven by the stator, there is no rotation of the camshaft 14th relative to the crankshaft so that the camshaft 14th remains the same in its phase angle. However, the rotor will 24 driven by the stator, so that for example the rotor 24 opposite the camshaft 14th is accelerated or decelerated, this is done via the transmission 22nd to a relative rotation between the camshaft 14th and the crankshaft. For example, a transmission of a speed of the rotor 24 and its direction of rotation to a controller for regulating and thus operating the electric motor 10 be provided. The controller is, for example, a component of an electronic computing device designed, for example, as an engine control device 34 , which may include the aforementioned commutation electronics. The electronic computing device 34 provides a control signal, for example 36 ready by means of which the electric motor 10 is controlled and thus operated. The electric motor 10 , especially the sensors 32 , provide a so-called speedometer signal, for example 38 ready, which the respective, by means of the respective sensor 32 detected rotary position of the rotor 24 characterized. The speedometer signal 38 is used by the electronic computing device 34 received, wherein the electronic computing device 34 the control signal 36 depending on the speedometer signal 38 provides. The electronic computing device thus controls 34 by means of the control signal 36 the electric motor 10 depending on the received speedometer signal 38 on, whereby, for example, the electric motor 10 depending on the speedometer signal 38 by means of the electronic computing device 34 via the control signal 36 is regulated.

Furthermore, it is provided, for example, that the camshaft sensor 18th a signal 40 characterizes which respective, by means of the camshaft sensor 18th detected rotary positions of the camshaft 14th characterized. The electronic computing device also receives 34 the signal 40 and another signal 42 , which characterizes the respective rotational positions of the crankshaft. the electronic computing device 34 provides the control signal 36 thus preferably as a function of the speedometer signal 38 , depending on the signal 40 and depending on the signal 42 ready, so preferably the electronic computing device 34 the electric motor 10 depending on the speedometer signal 38 , that is, as a function of the detected rotational positions of the rotor 24 , depending on the rotational positions of the camshaft 14th and operates, in particular regulates, as a function of the rotational positions of the crankshaft.

The aforementioned polarity change is, for example, a polarity change of the respective sensor 32 . Every change of polarity of the respective sensor 32 leads, for example, to a change in the state of the speedometer signal in addition to the switching state change of the bridge circuit described above 38 , on the basis of which changes in state the respective rotary position of the rotor 24 can be recognized. For example, the speedometer signal 38 on every falling or rising edge of the respective sensor 32 provided signal changed. It is also conceivable that for each falling or rising edge of the respective sensor 32 or of the respective, of the respective sensor 32 provided signal a falling edge of the speedometer signal 38 is produced. The direction of rotation of the rotor is also shown in the same signal 24 transfer.

Per complete revolution of the rotor 24 instructs the speedometer signal 38 for example thirty pulses, that is to say for example thirty falling or rising edges. The signal characterizing the rotational positions of the crankshaft 42 has for example 60-2 pulses per complete revolution of the crankshaft.

Will the speedometer signal 38 Counted with discrete time, the rotary positions and the wind speed or speed of the rotor 24 to be determined. Furthermore, for example, the speedometer signal 38 in comparison with the signal also known as the crankshaft signal 42 for operating, in particular regulating, the camshaft adjuster 20th used. Turns the servomotor or the rotor 24 at half the crankshaft speed, that is to say at half the speed of the crankshaft, for example, in the case of an equidistant signal, a change in the state of the sensors would have to occur for every fourth crankshaft sensor signal 32 or with the Hall sensors are determined and transmitted, especially if the servomotor has ten poles and exactly three sensors 32 has, which are designed, for example, as three Hall ICs. However, this is the ideal case, which does not necessarily occur in practice that has been found. In practice it was observed that the number of crankshaft signal edges varies between a respective speedometer signal. As a result, the controller, which controls or regulates the servomotor, for example, can be designed defensively and thus with a low P component so that these fluctuations do not lead to pseudo-control processes. In this way, excessive power consumption, excessive heat generation and other undesirable effects can be avoided. However, this has a negative effect on the control speed and smoothness. The aforementioned effects also result from the position error. Position errors, that is, deviations of the actual positions from the target positions, can thus lead to efficiency and / or power losses and / or to increased power consumption and / or to sluggish control behavior.

It was found that the equidistance of the speedometer signal 38 or the equidistance of the impulses of the speedometer signal 38 can be influenced by mechanical and electromagnetic tolerances. In particular, a position of a circuit board in a housing of the respective sensor can be influenced 32 , a position of a so-called sensitive point in the respective Hall IC, a positioning of the respective Hall IC on the board, a pole accuracy of a sensor magnet, temperature.

In order to be able to compensate for the respective deviation of the respective actual position from the respective target position, for example after the sensors have been installed 32 in their respective actual position at least one complete revolution of the rotor 24 causes. During the at least one complete revolution of the rotor, at least one rotational position of the rotor that occurs during the at least one complete revolution of the rotor is determined by means of the respective sensor 32 recorded. During the at least one complete revolution of the rotor, for example, at least one rotational position of the rotor that occurs during the at least one complete revolution of the rotor becomes 24 by means of an in addition to the sensors 32 provided detection device 44 recorded. In other words, after all the relevant components of the servomotor have been installed, i.e. the mechanical tolerances no longer change, the rotor will 24 rotated over at least 360 °, and the rotational position of the rotor 24 is recorded via an accurate, external measurement. The exact, external measurement is made by means of the acquisition device 44 accomplished. The at least one complete revolution is started, for example, at a reference position, for example on the basis of a bore in the output shaft, which is later used to assemble a clutch.

It becomes a result from the deviation of the respective actual position from the target position Deviation by means of the respective sensor 32 detected rotary position by means of the detection device 44 detected rotational position determined. The means of the detection device 44 detected rotational position is an ideal rotational position, which is also referred to as an ideal position. This means that every change in polarity of every sensor 32 for each pole and the deviation of the change in polarity or the rotational position measured by the change in polarity from the ideal position are determined, in particular calculated. This is also done, if necessary, by measuring electrical parameters on the coils during assembly. In particular, by means of the sensors 32 and by means of the detection device 44 During the at least one complete revolution, several rotational positions are recorded and compared with one another, so that respective deviations between the rotational positions are determined. Depending on the deviations determined by means of the sensors 32 detected rotational positions of the means of the detection device 44 detected rotational positions, respective correction values are determined, in particular calculated, and stored in a memory device of the commutation electronics, which is designed to store the electric motor 10 commutate depending on the correction values. This takes place, for example, during operation of the electric motor 10 such that the respective, by means of the respective sensor 32 recorded and sent to the electronic computing device 34 reported rotational position is corrected with the help of the correction value or by the correction value, thereby resulting from the correction value and the means of the respective sensor 32 detected rotary position an actual actual rotary position of the rotor 24 to determine, in particular to calculate. For example, the electric motor 10 commutated by means of the commutation electronics depending on the actual rotary position. For example, it is conceivable to calculate an average deviation from the deviations determined. The correction values or the deviations are stored, for example, in a correction value table that is stored, for example, in a microcontroller or in a logic of the servomotor. Depending on the correction value table or depending on the correction values and, for example, depending on a speed model by means of which the speed of the rotor 24 is calculated, the actual rotational position is calculated, for example. In particular, it is conceivable that on the basis of the correction values and, for example, also on the basis of the speed model from the speedometer signal 38 a corrected speedometer signal is calculated, which characterizes the actual actual rotational positions. In addition, a commutation signal is calculated, for example and in particular on the basis of the corrected tachometer signal, which, for example, is the control signal 36 is. Thus, for example, the electric motor 10 by means of the control signal 36 commutated as a function of the correction values and thus operated. As a result, the deviations of the means of the sensors 32 detected rotary positions from the actual rotary positions of the rotor 24 and thus the deviations of the actual positions from the target positions of the sensors 32 be compensated so that the electric motor 10 can be operated, in particular regulated, particularly efficiently.

List of reference symbols

10

Electric motor

12th

Valve train

14th

camshaft

16

Gas exchange valves

18th

Camshaft sensor

20th

Phase adjuster

22nd

transmission

24

rotor

26th

Output shaft

28

arrow

30th

Sensor wheel

32

sensor

34

electronic computing device

36

Control signal

38

Speedometer signal

40

signal

42

signal

44

Detection device

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed 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

• EP 1420510 A1 [0002]
• DE 19812966 A1 [0002]

Claims (3)

Method for compensating for a deviation of an actual position from a target position of at least one sensor (32), by means of which rotational positions of a rotor (24) of a commutated electric motor (10) can be detected, with the following steps: - effecting at least one complete revolution of the rotor (24) after the sensor (32) has been installed in its actual position; - During the at least one complete revolution of the rotor (24): Detecting at least one rotational position of the rotor (24) occurring during the at least one complete revolution of the rotor (24) by means of the sensor (32); - During the at least one complete revolution of the rotor (24): Detection of at least one rotational position of the rotor (24) occurring during the at least one complete revolution of the rotor (24) by means of a detection device (44) provided in addition to the sensor (32); - determining a deviation of the rotational position detected by means of the sensor (32) from the rotational position detected by means of the detection device (44) resulting from the deviation of the actual position from the target position; - as a function of the determined deviation: determining and storing at least one correction value in a storage device of a commutation electronics (34) which is designed to commutate the electric motor (10) as a function of the correction value. Procedure according to Claim 1 , characterized in that a servomotor (10) for setting a phase position of a camshaft (14) relative to a crankshaft of an internal combustion engine is used as the electric motor (10). Procedure according to Claim 1 or 2 , characterized in that a Hall sensor is used as the sensor (32).

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