WO2015154942A1

WO2015154942A1 - Method and device for determining the position of a machine part, regulating method for regulating the operation of an electric machine, and electric machine

Info

Publication number: WO2015154942A1
Application number: PCT/EP2015/055155
Authority: WO
Inventors: Igor Jantzen; Notker Amann
Original assignee: Zf Friedrichshafen Ag
Priority date: 2014-04-08
Filing date: 2015-03-12
Publication date: 2015-10-15
Also published as: DE102014206715A1

Abstract

The invention relates to a method for determining the position of a machine part using a plurality of sensor elements (121, 122, 123, 124, 125, 126) arranged along a movement path of the machine part, having the steps of reading a time value which is assigned to a detected position value (222), said detected position value (222) representing a machine part (110) position detected by a sensor element (122) of the plurality of sensor elements (121, 122, 123, 124, 125, 126); a step of reading a speed value, wherein the speed value represents an assumed speed of the machine part; and a step of ascertaining an assumed distance value using the time value, the speed value, and a maximum distance value. The assumed distance value is limited by the maximum distance value and represents an assumed distance between an assumed current position of the machine part and the detected position of the machine part.

Description

Method and device for determining the correctness of a machine part, method for regulating the operation of an electrical machine

and electric machine

The present invention relates to a method and a device for determining the position of a machine part, for example a rotor of an electric machine, to a control method for regulating an operation of an electrical machine and to an electric machine.

In electrical machines Hall sensors are often used to detect the situation. These solve, for example, six positions per electrical revolution. The electrical angle is therefore roughly quantized. It is desirable to have a position survey with a higher number of positions.

DE 10 2004 015 037 A1 deals with a method for determining the angular position of rotation of a shaft.

Against this background, the present invention provides an improved method and an apparatus for determining the position of a machine part, for example a rotor of an electric machine, an improved control method for controlling an operation of an electric machine and an improved electric machine according to the main claims. Advantageous embodiments will become apparent from the dependent claims and the description below.

A position determination of a machine part, for example a rotor of an electric machine, can be based on an assumed distance of a current position of the machine part to a detected and thus known position of the machine part. The assumed distance can be determined using a suitable determination rule, which can be based for example on an extrapolation method. By limiting the assumed distance to a maximum distance value, erroneous position determinations, ie positional determinations, in which a deviation between the presumed actual distance len position and an actual current position of the machine part is too large, avoided.

Advantageously, the approach described allows a precise position determination as would be possible with an incremental encoder sensor and a sine / cosine sensor, but can be realized much cheaper. Compared to known uses of Hall sensors, the approach described enables a more accurate and more reliable attitude determination compared to a known combination of Hall sensors and software algorithm based interpolation or a software algorithm based observer.

A method for determining the position of a machine part using a plurality of sensor elements arranged along a movement path of the machine part comprises the following steps:

Reading in a time value which is assigned to a detected position value, wherein the detected position value represents a position of the machine part detected by a sensor element of the plurality of sensor elements;

Reading in a speed value, the speed value representing an assumed speed of the machine part; and

Determining an assumed distance value using the time value, the speed value and a maximum distance value, wherein the assumed distance value is limited by the maximum distance value and represents an assumed distance between an assumed current position of the machine part and the detected position of the machine part.

The machine part may, for example, be a part of an electric, hydraulic or pneumatic machine or else a transmitter element, for example a magnet, for the sensor elements. The movement path can represent a circular path or a straight line. Thus, the machine part may be a part that performs a rotary movement or a linear movement. Accordingly, depending on the embodiment, the speed of the machine part may be an angular velocity or a linear velocity act. The machine part can be designed to emit a signal detectable by the sensor elements, for example a magnetic field. The sensor elements can be arranged so that the sensor elements in a movement of the machine part along the movement path in turn can detect the signal emitted by the machine part signal. Thus, each sensor element can be assigned a position of the machine part, which can be represented by a position value assigned to the respective sensor element. A time value can represent a time at which a position of the machine part is detected by a sensor element, that is, for example, the signal emitted by the machine part is detected by a sensor element. The speed of the machine part may be predetermined or determined, for example, from a series of preceding time values detected. In addition, a current time value can be used to determine the assumed distance. From the knowledge of the assumed AbStands and for example a last using the sensor elements detected position of the machine part can be concluded that the current position of the machine part and thus a position determination of the machine part are performed. The maximum distance value can be used to limit the assumed distance to plausible values for the distance. As a result, malfunctions can be avoided, for example, if the position determination of the machine part carried out, for example, is used to control a machine comprising the machine part.

According to one embodiment, the method may comprise a step of reading in the detected attitude value and a step of determining an assumed attitude value using the detected attitude value and the assumed distance value. In this case, the assumed position value can represent an assumed current position of the machine part. If the machine part represents a rotor of an electric machine, the current position can represent, for example, an angular position of the rotor. Due to the use of the maximum distance value in determining the assumed distance, critical values for the distance, in particular, too large distance values, can be excluded. For example, in the step of determining the assumed distance value, a provisional value may be determined using the time value and the speed value. In this case, the assumed distance value may be determined as the provisional value if the provisional value is smaller than the maximum distance value. On the other hand, the assumed distance value may be determined as the maximum distance value if the tentative value is greater than the maximum distance value. In this way, the provisional value may be determined, for example, by using a determination rule, and the obtained provisional value may be assigned to the assumed distance value until the tentative value reaches the maximum distance value. For example, tentative values greater than the maximum distance value may be considered implausible. By using the maximum distance value, it is possible to prevent such implausible provisional values from being assigned to the assumed distance value.

At this time, in the step of determining, the provisional value may be determined by using an extrapolation method or an interpolation method. By using such methods, the provisional value and thus also the assumed distance value can be determined very quickly and accurately.

According to an embodiment, the movement path may be circular. This is true, for example, when the machine part is mounted to rotate about an axis. Thus, the approach described can be advantageously used for a position determination of a rotor. In this case, the distance value may represent an angle.

For example, the maximum distance value may be specified as a value less than or equal to 90 °. Such a choice lends itself, for example, in an electrical machine, in which a deviation of more than 90 ° between the assumed current position and the actual position of the machine part can lead to malfunction in the control of the operation of the electric machine. Even if the machine part comes to a standstill immediately after detecting the position of the machine part by a sensor element, the assumed mene distance due to the predetermined maximum distance value of 90 ° does not rise above this value, so that even in such a case, a malfunction in the control of the operation of the electric machine can be avoided.

Also, the maximum distance value may be predetermined as a value corresponding to a distance between two adjacent sensor elements of the plurality of sensor elements. The determination of the assumed distance value may each be restarted in response to the reading of a new time value. Thus, it may be considered implausible if the assumed distance value had a value greater than the distance between two adjacent sensor elements. Setting the assumed distance value to such an implausible value can be avoided by the appropriate choice of the maximum distance value.

The method may include a step of reading in a previous time value. The preceding time value can be assigned to a previously recorded position value. The preceding detected position value may represent a preceding position of the machine part detected by a further sensor element of the plurality of sensor elements. The method may further include a step of determining the speed value using the time value and the previous time value. In this way, after providing two consecutive time values, a current speed value can be determined by two adjacent sensor elements and used to determine the assumed distance value.

According to one embodiment, the machine part may be a rotor of an electrical machine. The plurality of sensor elements may be magnetic field sensors. A magnetic field sensor may be, for example, a Hall sensor. Such sensors are already used for determining the position of rotors. In this way, the described approach can be used to improve existing systems. An operation of such an electric machine can be controlled by a suitable control method. A control method for controlling an operation of an electric machine according to an embodiment comprises a step of determining a position of the rotor of the electric machine by performing a method. Thus, a very accurate determination of the position of the rotor can be available for controlling the operation of the electric machine. This is advantageous, for example, if the rule is based on a field-oriented control (FOS).

A device for determining the position of a machine part using a plurality of sensor elements arranged along a movement path of the machine part has the following features:

a device for reading in a time value which is assigned to a detected position value, wherein the detected position value represents a position of the machine part detected by a sensor element of the plurality of sensor elements; means for reading in a speed value, the speed value representing an assumed speed of the machine part; and

means for determining an assumed distance value using the time value, the speed value and a maximum distance value, wherein the assumed distance value is limited by the maximum distance value and represents an assumed distance between an assumed current position of the machine part and the detected position of the machine part.

A device may be an electrical device that processes electrical signals, such as sensor signals, and outputs control signals in response thereto. The device may have one or more suitable interfaces, which may be formed in hardware and / or software. For example, in a hardware configuration, the interfaces may be part of an integrated circuit in which functions of the device are implemented. The interfaces may also be their own integrated circuits or at least partially consist of discrete components. In a software training, the Interfaces software modules that are available for example on a microcontroller in addition to other software modules.

The device can advantageously be used in conjunction with an electrical machine. Such an electric machine may comprise a rotor and a stator having a plurality of sensor elements arranged along a movement path of the rotor and also a device for determining a position of the rotor. Thus, the approach described can be advantageously used as a supplement to a known electrical machine.

A computer program product with program code which can be stored on a machine-readable carrier such as a semiconductor memory, a hard disk memory or an optical memory and is used to carry out the method according to one of the embodiments described above if the program is installed on a computer or a device is also of advantage is performed.

The invention will be described by way of example with reference to the accompanying drawings. Show it:

Fig. 1 is a schematic representation of an electrical machine with a device according to an embodiment of the present invention;

FIG. 2 is a schematic representation of a device according to an embodiment of the present invention; FIG.

3 is a flowchart of a method according to an embodiment of the present invention;

4 is a schematic representation of a rotor according to an embodiment of the present invention;

5 shows a graphic representation for determining the position of a machine part;

6 is a graphical representation of a speed change of a machine part; and

Fig. 7 is a graphical representation for determining the position of a machine part, according to an embodiment of the present invention. In the following description of preferred embodiments of the present invention, the same or similar reference numerals are used for the elements shown in the various figures and similarly acting, wherein a repeated description of these elements is omitted.

1 shows a schematic representation of an electrical machine 100 with a device 102 according to an embodiment of the present invention. The electric machine 100 has a rotor 1 10 and a stator 1 12. Six sensor elements 121, 122, 123, 124, 125, 126 are arranged on the stator 1 12 by way of example.

The rotor 1 10 is rotatably mounted about a rotor axis. The rotor 1 10 has at least one magnet, depending on the embodiment, at least one electromagnet or a permanent magnet on. The at least one magnet represents a donor element for the sensor elements 121, 122, 123, 124, 125, 126. The sensor elements 121, 122, 123, 124, 125, 126 are arranged around the rotor 110 and designed to be one of To sense the rotor 1 10 generated magnetic field. Upon rotation of the rotor 110 about the rotor axis, the sensor elements 121,

122, 123, 124, 125, 126 are exposed in turn to the magnetic field of the rotor 1 10. The sensor elements 121, 122, 123, 124, 125, 126 are each designed to output a sensor signal which is generated by a respective sensor element 121, 122, 123,

124, 125, 126 detected magnetic field and thus the position of the rotor 1 10 images. By evaluating a sensor signal of one of the sensor elements 121, 122,

123, 124, 125, 126, it can be determined at what point in time the rotor 1 10 was in the position which could be detected by the latter of the sensor elements 121, 122, 123, 124,

125, 126 can be detected.

The device 102 according to this embodiment has an interface for receiving the sensor signals of the sensor elements 121, 122, 123, 124, 125, 126. The device 102 is designed to perform a position determination with respect to a position, in this case an angular position, of the rotor 110, using the sensor signals. For determining the position of the rotor 1 10, the device 102 is designed to determine, based on the sensor signals, points in time at which the rotor 1 10 had in each case assumed a position which was determined by one of the sensor elements 121,

122, 123, 124, 125, 126 has been detected. The device 102 is further designed to determine a rotational speed of the rotor 110 based on two successive points in time and a known distance between two adjacent sensor elements 121, 122, 123, 124, 125, 126. Due to the rotational speed of the rotor 1 10 moves after he has taken a last detected position on, so that at a subsequent time, a distance between the last detected position and a current position of the rotor 1 10 is. The device 102 is designed in response to a last detected by one of the sensor elements 121, 122, 123, 124, 125, 126 position of the rotor 1 10 using the last determined rotational speed of the rotor 1 10, the distance between one at a current time assumed current position of the rotor 1 10 and the last detected position of the rotor 1 10 to determine and provide, for example, as an assumed distance value 130. In order to prevent the assumed distance value 130 from assuming that the rotor 110 is at a standstill at later actual times, the device 102 has a memory 135 for a maximum distance value 136 according to this exemplary embodiment. Device 102 is configured in accordance with this embodiment to provide the assumed distance value 130 only with values that are less than or equal to maximum distance value 136 in one embodiment.

The maximum distance value 136 may, for example, correspond to an angle value which corresponds to an angle of 360 ° divided by the number of sensor elements 121, 122, 123, 124, 125, 126. Thus, the maximum distance value 136 may be a distance between two adjacent sensor elements 121, 122,

123, 124, 125, 126 correspond. Alternatively, the maximum distance may also have a value which is greater than the distance between two adjacent sensor elements 121, 122, 123, 124, 125, 126. According to one exemplary embodiment, the device 102 is designed to combine the assumed distance value 130 with the last detected position of the rotor 110, for example by summation, and thereby to determine an assumed position value representing an assumed current position of the rotor 110. The device 102 may be configured to provide the assumed attitude value instead of or in addition to the assumed distance value 130.

According to one embodiment, a controller 137 is provided which is configured to perform a control method for controlling an operation of the electric machine 100. The control device 137 is designed to receive the assumed distance value 130 or an assumed position value of the rotor 110 via an interface to the device 102. Further, the controller 137 is configured to receive one or more current values or voltage values 138 sensed at phases of the electric machine 100. The control device 137 is designed to use the received values 130, 138 to determine a control signal 139 for setting at least one operating parameter of the electric machine 100 and to provide it to a control input of the electric machine 100. For example, the controller 137 may be configured to perform field-oriented control of the electric machine 100. In one embodiment, the device 102 may be considered part of the controller 137.

According to one exemplary embodiment, the device 102 may have an interface to an evaluation device on the input side and be designed to generate specific values, for example time values, position values and / or speed values, from the evaluation device based on the sensor signals of the sensor elements 121, 122, 123, 124, 125, 126 to recieve. A time value may depict a time of detection of a position of the rotor 110 by one of the sensor elements 121, 122, 123, 124, 125, 126. A position value can be a position of the rotor 1 10 detected by one of the sensor elements 121, 122, 123, 124, 125, 126. A speed value can map a speed of the rotor 110. 2 shows a schematic illustration of a device 102 for determining the position of a machine part using a plurality of sensor elements arranged along a movement path of the machine part according to an exemplary embodiment of the present invention. This may be an embodiment of the device 102 shown in FIG. Thus, the machine part may be a rotor and the sensor elements may be magnetic field sensors.

The device 102 has a read-in device 241 which is designed to receive a time value assigned to a detected position value. In this case, the detected position value represents a position of the machine part detected by a sensor element of the plurality of sensor elements. The position value can in particular represent a position of the machine part last detected by one of the sensor elements and thus assumed to be known. About the time value is also known at what time the machine part had taken the recorded position. Furthermore, the device 102 comprises another read-in device 243, which is designed to read in a speed value which represents an assumed speed of the machine part. In order to determine a distance between a current position of the machine part and the last detected position resulting from the assumed speed at a current time defined by the time value, the device 102 has a determination device 245 which is designed to have an assumed distance value 130 using the time value, the speed value and a maximum distance value. In this case, the determination means 245 may further use the current time or a time difference between the current time and the time value. In this case, the determination device 245 is designed to limit the assumed distance value 130 by the maximum distance value, so that the assumed distance value 130 can assume a maximum value predetermined by the maximum distance value.

3 shows a flow chart of a method for determining the position of a machine part using a plurality of sensor elements arranged along a movement path of the machine part according to an embodiment. Example of the present invention. For example, steps of the method may be performed using devices of the device described with reference to FIG.

The method comprises a step 341 of reading in a time value, a step 343 of reading in a speed value and a step 345 of determining an assumed distance value 130 using the time value, the speed value and a maximum distance value. The steps 341, 343, 345 can be executed repeatedly consecutively. In response to the reading in of a new time value in step 341, the assumed distance value 130 can be set to zero and increased in magnitude starting from zero until a further time value is read in by a renewed step 341, or until the assumed distance value 130 has been increased in amount, the assumed distance value 130 has reached the predetermined maximum distance value. If so, the assumed distance value 130 is not increased any further.

According to an embodiment, the method further comprises

Step 347 of reading the detected attitude value and a step 349 of determining an assumed attitude value 350 using the detected attitude value and the assumed distance value 130. The assumed position value represents the assumed current position of the machine part.

4 shows a schematic representation of an electrical machine 100 according to an embodiment of the present invention. This may be, for example, the electric machine 100 described with reference to FIG. 1.

Shown are positions of six sensor elements 121, 122, 123, 124, 125, 126, which are arranged on a circular path parallel to a circular path of movement of the rotor about the rotor axis. The first sensor element 121, also called Hall sensor A, is arranged at 0 ° or 360 °. The second sensor element 122, also called Hall sensor B, is arranged at 60 °. The third sensor element 123, also called Hall sensor C, is arranged at 120 °. The fourth sensor element 124, also called Hall sensor D, is arranged at 180 °. The fifth sensor element 125, also called Hall sensor E, is arranged at 240 °. The sixth sensor element 126, also called Hall sensor F, is arranged at 300 °. Instead of six sensor elements 121, 122, 123, 124, 125, 126, another suitable number of sensor elements 121, 122, 123, 124, 125, 126 may also be used.

The first sensor element 121 is arranged so that it can detect a position of 0 ° of the rotor element characterized by a first position value 221, i. using the first sensor element, the time can be detected at which the rotor has an angular position of 0 °. The second sensor element 122 is arranged such that it can detect a position of 60 ° of the rotor element characterized by a second position value 222; the third sensor element 123 is arranged such that it detects a position of 120 ° of the rotor element characterized by a third position value 223 The fourth sensor element 124 is arranged such that it can detect a position of 180.degree. of the rotor element identified by a fourth position value 224; the fifth sensor element 125 is arranged such that it has a position of 240.degree. of the position indicated by a fifth position value 225 Rotor element can detect and the sixth sensor element 126 is arranged so that it can detect a characterized by a sixth position value 226 position of 300 ° of the rotor element. The sensor elements 121, 122, 123, 124, 125, 126 may each be designed to output the position values 221, 222, 223, 224, 225, 226 representing the respective layers. Alternatively, a downstream evaluation orientation can be designed in order to provide the corresponding position values 221, 222, 223, 224, 225, 226 by evaluating sensor signals of the sensor elements 121, 122, 123, 124, 125, 126. Each position value 221, 222, 223, 224, 225, 226 can be assigned a time value by which a time of detection of the position of the rotor represented by the respective position value 221, 222, 223, 224, 225, 226 can be indicated.

Between two adjacent sensor elements 121, 122, 123, 124, 125, 126 is in each case a sector. 4, a first sector 461 is located between the sen- sensor elements 121, 122 and a second sector 462 between the sensor elements 122, 123. Furthermore, further sectors 463, 464, 465, 466 are plotted.

An arrow indicates an actual current position 475 of the rotor, also referred to as (1), In the event that the rotor moves counterclockwise, the rotor could be last detected by the second sensor element 122, so that the second position value 222 Until the time at which the rotor can be detected by the third sensor element 123, an assumed current position of the rotor is determined over an assumed distance of the assumed current position from the last detected position of the rotor. For this purpose, a speed of the rotor may have previously been determined, for example using time values at which two adjacent sensor elements 121, 122, 123, 124, 125, 126, here for example the sensor elements 121, 122, could each detect the position of the rotor.

FIG. 4 shows a view directly onto the machine. In Fig. 5, the timing of the Hall sensors in a left-handed machine is shown below. The staircase function shown in Fig. 5 shows the last passed from the rotor Hall sensor. A machine with Hall sensors has only these six position signals of the staircase function available.

FIG. 5 shows a graphical representation for determining the position of a machine part, for example an electric machine, as described with reference to FIG. 4.

The abscissa shows the time t and the ordinate the position of the rotor in degrees. Time values 521, 522, 523, 524, 525, 526 are plotted on the ordinate, which correspond to times at which position values 221, 222, 223, 224, 225, 226 of the rotor were detected using the individual sensor elements.

Referring to FIG. 4, the first time value 521 represents the time at which the first sensor element 121 detects that the rotor is in the first position represented by the first position value. The first position value 221 is up the abscissa is plotted according to the position of the first sensor element 121 at 0 °. The second time value 522 represents the time at which the second sensor element 122 detected that the rotor is in the second position represented by the second position value 222. The second position value 222 is plotted on the abscissa corresponding to the position of the second sensor element 122 at 60 °. The third time value 523 represents the time at which the third sensor element 123 detects that the rotor is in the third position represented by the third position value 223. The third position value 223 is plotted on the abscissa corresponding to the position of the third sensor element 123 at 120 °. The fourth time value 524 represents the time at which the fourth sensor element 124 sensed the rotor is in the fourth position represented by the fourth position value 224. The fourth position value 224 is plotted on the abscissa corresponding to the position of the fourth sensor element 124 at 180 °. The fifth time value 525 is the time at which the fifth sensor element 125 detects that the rotor is in the fifth position represented by the fifth position value 225. The fifth position value 225 is plotted on the abscissa corresponding to the position of the fifth sensor element 125 at 240 °. The sixth time value 526 represents the time at which the sixth sensor element 126 sensed the rotor is in the sixth position represented by the sixth position value 226. The sixth attitude value 226 is plotted on the abscissa corresponding to the position of the sixth sensor element 126 at 300 °. The further first time value 521 'represents the time at which the rotor was again detected by the first sensor element 121 due to one complete revolution of the rotor in the first position represented by the first position value 221.

Due to the limited number of sensor elements, the current position 475 of the rotor, as shown in FIG. 4, can not be detected directly, that is, measured by the sensor elements. Assuming that the rotational speed ω of the rotor is constant, an assumed position φ (ω = constant) can be determined over a straight line passing through the positions detected at the times 521, 522, 523, 524, 525, 526 221, 222, 223, 224, 225, 226 is guided. The so ascertainable position is indicated by an arrow 575. FIG. 6 shows a graphic representation of a speed change of a machine part, for example the rotor of the electric machine shown with reference to FIG. 4. The abscissa shows the time t and the ordinate the speed ω of the rotor. By a count 677 an actual speed of the machine is shown. The speed decreases from a value greater than ω _η is down to zero. The value ω _η was determined as the average rotational speed of the rotor when passing through the first sector 461.

The rotational speed ω _η is calculated between the first time value 521 and the second time value 522. The rotational speed ω _η is the average rotational speed of the rotor in the sector 461. The rotational speed ω _η is used for the extrapolation of the position in the subsequent second sector 462 between the second and the third Hall sensor.

Fig. 7 is a graphical representation for determining the position of a machine part, according to an embodiment of the present invention. In this case, the course of the rotational speed of the machine shown in FIG. 6 is taken as the basis. The representation corresponds to the illustration already described with reference to FIG.

A position of the rotor extrapolated assuming a constant rotational speed ω _η is shown by a straight line 781. A position of the rotor extrapolated using the rotational speed ω _η and limited by using a maximum distance value, which is 60 ° in this embodiment, is shown by a curve 350. A first section of the profile 350 follows the position of the rotor which is extrapolated assuming a constant rotational speed ω _η , that is to say the straight line 781. Upon reaching the predetermined maximum distance value, the curve 350 bends and extends horizontally toward the third position of the rotor of 120 °, which is detected by the third sensor element at the third time value 523. Thus, assumed distance values represented by the curve 350 may not become larger than a distance between two adjacent sensor elements.

The orientation is based on a Hall sensor with limited extrapolation or limited interpolation. The calculated position of the rotor results from <p (t) = (phall + ΔφΙι, η

Acpl _im = ω _η (t -thaii), for Acpl _in <= 60 °; and

Ac lim = 60 °, for Ac lim> 60 ° where:

⁽ haii: location of the last happened Hall

thaii: Time when passing the last happened Hall

ω _η : speed

Here, the value of 60 ° is an example of the sector size.

Thus, to determine an assumed attitude value cp (t) of the rotor at a current time, which is in a time interval between a time of passing the last reverberation and not yet passing a next reverberation, the sum over that of the last reverberated reverb Sensor detected position value (p _ha n and the assumed distance value Acpl _im formed.

Reference to the preceding figures will be described in more detail in the following embodiments of the present invention.

According to one embodiment, a location detection of electrical machines 100 based on Hall sensors 121, 122, 123, 124, 125, 126 and limited extrapolation 350 is described. Consider an electric machine 100 equipped with Hall sensors 121, 122, 123, 124, 125, 126. In one revolution of the rotor 1 10 six layers, hereinafter also called positions, of the rotor 1 10 are detected. The detected six plies are represented by the attitude values 221, 222, 223, 224, 225, 226. The area between the

Hall's 121, 122, 123, 124, 125, 126 is referred to as a sector. There are accordingly six sectors 461, 462, 463, 464, 465, 466. Thus, each sector 461, 462, 463, 464, 465, 466 is 60 ° in size, as shown in FIG. Once the rotor 1 10 - the current position 475 of the rotor 1 10, as shown in Fig. 4, with angle (p _is called - a Hall sensor 121, 122, 123, 124, 125, 126 happens with knowledge of the direction of rotation, in which sector 461, 462, 463, 464, 465, 466 the rotor 110 is located.

For the use of a complex field-oriented control, the six Hall signals of the sensors 121, 122, 123, 124, 125, 126 per revolution are not sufficient. An attempt is made to linearly extrapolate the exact position 475 of the rotor, knowing the speed 677, in order to be able to calculate the position between the Hall sensors 121, 122, 123, 124, 125, 126. As long as the rotational speed of the rotor 677 1 10 does not change, corresponding to the extrapolation of the actual location 475. Once the speed changes 677, 781 performs an extrapolation of the position deviations of the actual position, as _shown in FIG. 7 between (p 475 and the interpolated layer 781 in the initial region after the second time value 522. This results from the fact that a speed change can only be detected when passing through the next reverb 123. In the extreme case, this results in the machine 100 already standing, this but could not yet be determined and can not be determined, just because no Hall sensor 121, 122, 123, 124, 125, 126 is more happening.The extrapolation 781 of the position is performed at a speed ω _η , the between the two It becomes critical if the calculated position deviates more than 90 ° from the actual position, indicated in FIG. 7 between (p _is 475 and the interpolated layer 781 in the end region before the third time value 523. Such a deviation is to be avoided since it can lead to uncontrollable or unstable behavior in electrical machines 100.

In the extrapolation of the position of the rotor 1 10, the positions of the Hall sensors 121, 122, 123, 124, 125, 126 corresponding to the detectable attitude values 221, 222, 223, 224, 225, 226 are used as a starting point. If the second Hall sensor 122 with a positive direction of rotation - passed counterclockwise - from the rotor 1 10, it is known that the rotor 1 10 in the second sector 462nd is as shown in Fig. 4. The extrapolation 781 would then be performed by 60 °, ie the second position value 222 detected by the second Hall sensor 122, starting with the last calculated speed ω _η and the time elapsed since the second position value 222 was detected or displayed by the second Hall sensor 122. For example, position 781 is calculated every millisecond. Where:

Phi_calculated (t) = 60 ° + t ^* speed

In this case, t is the time that has elapsed since passing the last Hall sensor 122.

By way of illustration, it is assumed that the actual speed ω has dropped to zero after passing through the second Hall sensor 122. However, the last known speed ω _η is not equal to zero. As long as no further Hall sensor 123 is passed by the rotor, the value "t" for the elapsed time after the detected passing of the second Hall sensor 122 by the rotor 110 in the above equation will increase. Phi_berechnet the critical difference of 90 ° between Phijst, current position 475 of the rotor 1 10 and Phi_berechnet - calculated position 781 of the rotor 1 10 - exceed. A deviation between the calculated position 781 and the actual position 475 may lead to incorrect manipulated variables for the machine 100 and therefore to a wrong torque of the machine 100. As long as the deviation remains below 90 °, this can be accepted depending on the intended use of the electric machine 100. Currently, the field-oriented control is realized with significantly more expensive sensors (incremental encoder / sine / cosine), which allow a very high resolution of the situation, but are relatively expensive.

In order to avoid a deviation above 90 °, a limitation of the extrapolation 781 (t ^* rotational speed) to a maximum distance value 136 is performed. The maximum distance value 136 is here given by the maximum possible sector size, in this case 60 °, as shown in Fig. 7 by the kink in the curve 350, which is a limited extrapolation. The rotor 1 10 can not be further away from the last Hall sensor 122 than 60 °, otherwise the next Hall sensor 123 would be passed. This ensures that the maximum deviation of the position is always within the permissible range, with a maximum of 60 °.

By limiting the extrapolation 781 and thus the maximum deviation from the actual position, it is possible to use a field-oriented control without the critical case of a deviation exceeding 90 ° being able to occur.

The described limitation of the extrapolation 781 leads to the method being called interpolation.

The number of Hall sensors 121, 122, 123, 124, 125, 126 is chosen by way of example only. With the increase of the Hall signals per revolution of the rotor 1 10, the sector size of the sectors 461, 462, 463, 464, 465, 466 can be reduced. This would further reduce the maximum possible error.

The described approach can be applied to any quantized position signals. For example, this can improve the position determined by an incremental encoder.

In the described embodiments, the linear extrapolation of the layer is limited, but the method is also applicable with other extrapolation methods. In this case, the limitation of the extrapolation can be considered as interpolation, so that interpolation methods can also be used.

To control the operation of the machine 100, for example signals of the Hall sensors 121, 122, 123, 124, 125, 126 and, secondly, signals 138 from current measurements to two phases of the electric machine 100 can be used.

Although the preceding embodiments are related to a machine with a rotating machine part, the approach described is not limited to such machines, but can also on machines with a Linear movement exporting machine part, as is the case for example in a linear motor, are used. In this case, the corresponding sensor elements may be arranged in a row.

The embodiments described and shown in the figures are chosen only by way of example. Different embodiments may be combined together or in relation to individual features. Also, an embodiment can be supplemented by features of another embodiment. Furthermore, method steps according to the invention can be repeated as well as carried out in a sequence other than that described. If an exemplary embodiment comprises a "and / or" link between a first feature and a second feature, this can be read so that the embodiment according to one embodiment, both the first feature and the second feature and according to another embodiment, either only the first Feature or only the second feature.

REFERENCE CHARACTERS

100 electric machine

102 device

1 10 stator

1 12 rotor

121 first sensor element

122 second sensor element

123 third sensor element

124 fourth sensor element

125 fifth sensor element

126 sixth sensor element

130 assumed distance value

135 memory

136 maximum distance value

137 control device

138 current / voltage values

139 control signal

221 first location

222 second location

223 third location

224 fourth location

225 fifth position

226 sixth position

241 reading device

243 reading device

245 Investigation facility

341 step of reading

343 step of reading

345 step of the determination 461 first sector

462 second sector

463 third sector

464 fourth sector

465 fifth sector

466 sixth sector

475 actual current position of the rotor

521 first time value

522 second time value

523 third time value

524 fourth time value

525 fifth time value

526 sixth time value

521 'further first time value

575 assumed situation

677 speed

781 extrapolate location

783 assumed distance values

Claims

claims

1 . Method for determining the position of a machine part (1 10) using a plurality of sensor elements (121, 122, 123, 124, 125, 126) arranged along a movement path of the machine part (1 10), characterized in that the method comprises the following steps:

Reading in (341) a time value (522) associated with a detected position value (222), the detected position value (222) including one of a sensor element (122) of the plurality of sensor elements (121, 122, 123, 124, 125, 126 ) detected position of the machine part (1 10) represents;

Reading (343) a speed value (ω _η ), wherein the speed value (ω _η ) represents an assumed speed of the machine part (1 1 0); and

Determining (345) an assumed distance value (130) using the time value (522), the velocity value (ω _η ), and a maximum distance value (136), the assumed distance value (130) being limited by the maximum distance value (136) and a assumed distance between an assumed current position of the machine part (1 10) and the detected position of the machine part represented.

A method according to claim 1, characterized in that the method comprises a step (345) of reading in the detected attitude value (222) and a step (349) of determining an assumed attitude value (350) using the detected attitude value (222) and the assumed distance value (130), wherein the assumed position value (350) represents the assumed current position of the machine part (1 10).

Method according to one of the preceding claims, characterized in that, in step (345) of determining the assumed distance value (130), a provisional value (781) is determined using the time value (522) and the speed value and the assumed distance value (130). is determined as the provisional value (781) when the provisional value (781) is smaller than the maximum distance value (136), and the assumed distance value (130) as the maximum distance value (136) is determined if the provisional value (781) is greater than the maximum distance value (136).

The method according to claim 3, characterized in that in the step of determining (345) the provisional value (781) is determined using an extrapolation method or an interpolation method.

5. The method according to any one of the preceding claims, characterized in that the movement path is circular and the maximum distance value (136) is specified as a value less than or equal to 90 °.

6. Method according to one of the preceding claims, characterized in that the maximum distance value (136) is predetermined as a value which corresponds to a distance between two adjacent sensor elements (121, 122) of the plurality of sensor elements (121, 122, 123, 124, 125, 126).

Method according to one of the preceding claims, characterized in that the method comprises a step of reading in a preceding time value (521) associated with a previously acquired position value (221), the preceding detected position value (221) being one of another Sensor element (121) of the plurality of sensor elements (121, 122, 123, 124, 125, 126) represents the detected previous position of the machine part (1 10), and a step of determining the speed value (ω _η ) using the time value (522) and the previous time value (521).

8. The method according to any one of the preceding claims, characterized in that the machine part (1 10) is a rotor of an electric machine (100) and the plurality of sensor elements (121, 122, 123, 124, 125, 126) magnetic field sensors.

9. A control method for controlling an operation of an electrical machine (100), characterized in that the control method comprises a step of best immensely a position of the rotor of the electric machine (100) using a method according to claim 8 comprises.

10. Device (102) for determining the position of a machine part (1 10) using a plurality of along a movement path of the machine part (1 10) arranged sensor elements (121, 122, 123, 124, 125, 126), characterized in that the device having the following features:

means (241) for reading in a time value (522) associated with a detected position value (222), wherein the detected position value (222) comprises one of a sensor element (122) of the plurality of sensor elements (121, 122, 123, 124, 125, 126) detected position of the machine part (1 10) represents;

means (243) for reading a speed value, the speed value representing an assumed speed of the machine part (110); and

means (245) for determining an assumed distance value (130) using the time value (522), the speed value and a maximum distance value (136), the assumed distance value 130) being limited by the maximum distance value (136) and an assumed distance between an assumed current position of the machine part (1 10) and the detected position of the machine part (1 10) represented.

1 1. Electric machine (100) having a rotor as a machine part (1 10) and a stator (1 12) with a plurality of arranged along a movement path of the rotor sensor elements (121, 122, 123, 124, 125, 126), characterized in that the electric machine (100) comprises a device (102) according to claim 10 for determining a position of the rotor.