WO2002084849A1

WO2002084849A1 - Method and device for determining the rotational position of an electric induction machine

Info

Publication number: WO2002084849A1
Application number: PCT/DE2002/000769
Authority: WO
Inventors: Anton Dukart; George Blosch; Anton Paweletz
Original assignee: Robert Bosch Gmbh
Priority date: 2001-04-11
Filing date: 2002-03-01
Publication date: 2002-10-24
Also published as: DE10118052A1

Abstract

The invention relates to a method and device for determining the rotational position of an electric induction machine (1), which can be commutated in an electronic manner. The inventive device comprises a rotor support (12), which accommodates a rotor (22), and comprises a stator coil (15, 16), which is arranged inside a housing (3) in a rotationally fixed manner. A magnetized ring element (26) is assigned to the rotor support (12) and interacts with rotationally fixed sensor elements (24, 25), e.g. magnetoresistive sensors or hall sensors, which detect the course of induction (30, 31). Signals, which are offset with regard to one another at an electric angle, of both sensor elements (24, 25) are determined from the periodically occurring magnetic reversal of the sensor elements (24, 25).

Description

Method and device for detecting the rotational position of an electrical rotating field machine

Technical field

Electronically commutable motors are increasingly being used as drive units for electromechanical actuators in the automotive industry. In order to achieve the required moments, actuating forces and the required positioning accuracies as well as to take into account the dynamic properties of such commutatable electric induction machines, an exact angular position detection of such electric induction machines is necessary. The angular position detection is based on the scanning of the angular position of the motor shaft with the aid of an additional device which is installed on the motor flange and is usually stored separately for the demanding positioning drives or can be integrated into the electrical induction machine.

State of the art

From DE 195 03 492 a device for driving and determining the position of an actuating system has become known. According to this solution, an actuating system is provided in which an adjustment is carried out with the aid of a reluctance motor. By evaluating the position-dependent inductivities of the motor, the position can be continuously determined using the observer principle without an additional sensor. The drive also acts as a sensor here. By using an inductivity measurement method that is independent of the associated power electronics, the fluctuations in the supply voltage have no influence on the accuracy of the position detection of the electrical machine. This possibility of position detection is linked to the use of a reluctance motor as an electrical induction machine; If other drive motors are used, their position is detected by magnetic, electromagnetic, magnetoresistive, capacitive or optical sensors. In the solution According to DE 195 03 492, the inductances in multi-pole hollow cell clasps are too dependent on the manufacturing tolerances. Furthermore, control disturbances integrated in the inductance measurement with a high clock frequency on the drive are to be expected z. B. by the capacitive couplings.

If hollow-shaft motors are used as the electrical induction machine, hollow-shaft incremental encoders, hollow-shaft resolvers or electromagnetic scanning of magnetic reluctance are usually used, e.g. Magnetic gears are used.

In the case of electromagnetic actuators, the electrical energy is converted into mechanical energy via intermediate translation or gear stages, e.g. converted into a translatory movement. The mechanical contact to the motor shaft of the electrical induction machine can be blocked, since the motor shaft in the middle of the electromechanical actuator is completely converted and is therefore not accessible. Although there is contact with rotating or linearly moving parts, a gear ratio or a translatory movement has already taken place, e.g. by means of a ball screw. In view of the requirements for the regulation or the metering of an axial force, the angular errors resulting from this type of scanning, which result in particular from the inevitable play between the built-in mechanical components and the bending or torsional stiffness of the mechanical components, are not permitted result.

Presentation of the invention

With the solution proposed according to the invention, it is possible to provide inexpensive, easy-to-manufacture, but highly accurate position detection on electrical rotary field machines configured as hollow shaft motors, in which this can be determined without direct mechanical contact with the shaft, the rotational position of which is to be exactly determined. By assigning two sensor elements in the housing that are offset electrically by exactly 1/4 of the magnetization pole pitch (corresponding to 90 °), be it magnetoresistive sensors or Hall sensors, the position detection can be determined without contact by detecting the magnetic induction, so that the tolerances or playful measurement of the angular position of the electrical rotary field machine can be avoided by mechanical components. Advantageously, the sensor elements, for example accommodated on the motor bearing and positioned opposite one another, can be provided with a shield in which the magnetic lines of the stray field of the motor are concentrated without the resulting ones Falsify analog signals from the magnetoresistive sensor elements or the Hall sensors.

With the solution proposed according to the invention, an improvement in the detection accuracy of the rotational position of the electric induction machine can be achieved. The position errors are only related to the pole pitch of the electrical machine and are designed so that they are only a fraction (e.g. 1/200) of this pole pitch. This is particularly important if the electrical induction machine to be monitored with regard to its rotational position position works as a high torque which is followed by only a slight mechanical transmission. Such electrical induction machines generally have a relatively large number of poles, so that the solution proposed according to the invention can be used to prevent electrically operable window surfaces, sunroofs or the like due to insufficiently accurate position detection of the drive shaft of the electric induction machine assigned to them have moved insufficiently into their corresponding closed positions.

In particular, the number of poles of the sensor can advantageously be adapted to the number of poles of the motor, e.g. with a 24-pole motor (2p = 24) the number of poles of the sensor ring will also be 26, 2p = 24. The analog sensor signals with which a precise position description (angular position of the rotor) within a pole pitch can be used can also be used as the basis for the motor control (e.g. as reference curves for the current controller). At the same time, the magnetic axis of the rotor can cover the magnetic axis of the sensor ring in a defined manner. This would mean that e.g. reaching the maximum in time of the sine sensor signal (sensor element 24) corresponds exactly to the specific position of the axis of one of the rotor poles with respect to a correspondingly selected reference point on the stator. The number of poles of the sensor can be the same as the number of poles of the motor or a multiple of the number of motor poles. By appropriate alignment of the sensor ring (26) together with the yoke elements 35 on the axis of symmetry of one of the rotor poles, a clear rotor position detection can be realized within a motor pole division (without an additional electronic offset setting being necessary).

drawing

The invention is described in more detail below with reference to the drawing. It shows:

1.1 shows a section through an actuator with a drive from a cylindrical three-field machine and conversion of the rotation into a linear movement with a concentric gear spindle set,

FIG. 1.2 shows a detailed illustration of the motor bearing of the electrical induction machine,

FIG. 1.3 shows an enlarged representation of the sensor elements accommodated on the engine mount,

FIG. 2 shows the course of the axial component of the induction in the gap between the magnetic ring and sensors,

FIG. 3.1 shows a magnetic sensor ring with the course of the magnetic induction (Bfz) and. To be detected by the sensor elements

FIG. 3.2 shows an enlarged detail with drawn angular divisions τ from a segmented magnetized sensor ring.

variants

1 shows a section through an electrical rotary machine designed as a concentric, electrical hollow shaft motor.

The electrical induction machine 1 shown in section in FIG. 1 is configured as a hollow shaft motor. A shown in dashed lines closure part 2 ^closes' an only schematically reproduced output 4, which in turn rotationally fixed on a rotating housing on a hollow shaft 13 rotor carrier 12 is added. The electrical induction machine 1 configured as a hollow shaft motor as shown in FIG. 1.1 comprises a spindle 5 which contains a bearing journal 6. Between the bearing journal 6 and the spindle sleeve surrounding it, bearing bodies 7, which are provided as spherical segments as shown in FIG. 1.1, are accommodated. The spindle sleeve 8 is supported by means of an axial bearing 9 on a collar which is formed on the hollow housing shaft 13. On the outside of the spindle sleeve 8, which surrounds the bearing journal 6 and is rotatably received thereon, a radial bearing 10 is accommodated which is supported on the inside of the housing hollow shaft 13. The housing hollow shaft 13 in turn is part of the housing 3 of the electrical induction machine 1.

A rotor support 12 is rotatably received on the housing hollow shaft 13. The rotor support 12 is supported on the one hand on the outer ring of a motor bearing 19 and on the other hand is supported by a radial bearing 11 which is received on the hollow housing shaft 13 with an undercut. In addition, an annularly configured receiving element 23 is non-rotatably received on the housing shaft 13, on which sensor elements, which are not shown in FIG. A magnetizable sensor 26 is accommodated on the inner wall of the rotor carrier 12 in the area of the motor bearing 19, as shown in FIG. 1.1.

The rotor carrier 12, which is rotatably received on the housing hollow shaft 13 by means of the bearings 19 and 11, on the outside carries on the one hand the rotor 14 of the electric rotary field machine 1 the electrical induction machine 1 is held. A stator winding 16 is assigned to the stator 15, while connections are designated by reference number 17 as shown in FIG. 1.1. A motor air gap 18 is formed between the stator 15 and the rotor 14, which is preferably designed as a laminated core, in which the electrical forces between the stator 15 or the stator winding 16 and the laminated core of the rotor are effective.

A more detailed representation of the motor bearing of the electrical induction machine can be seen from the representation according to FIG. 1.2.

In FIG. 1.2, the receiving element 23, which is arranged in a rotationally fixed manner on the hollow housing shaft 13 and extends around it, is drawn out. On the side facing the magnetizable sensor ring 26, sensor elements 24, 25 which are electrically offset from one another by exactly 1/4 of the magnetization pole pitch (corresponding to 90 °) are accommodated. Alternatively, an additional pair of such sensor elements could be arranged offset by 180 ° on the opposite side. In this case, you could compensate for any radial play in the bearings. In the case of this alternative solution, the resulting signal from both sensor pairs 24, 25 should be determined separately and be processed further as an average. On the one hand, the sensor elements 24 and 25 can be designed as magnetoresistive sensor elements; the sensor elements 24 and 25 can also be Hall sensors. The sensor ring 26 is in turn enclosed by a shielding ring 28, the outer side of which lies against the inner side of the rotor carrier 12 as shown in FIG. 1.1. In addition to the ring-shaped extension Taking element 23, the motor bearing 19 is shown, which comprises an inner ring 22 and an outer ring 21, between which a spherical-shaped roller body 20 is received.

The magnetizable sensor ring 26 can be removed from the illustration according to FIG. 1.2 only to a limited extent, but is indicated by the reference numbers 29 and 34, respectively

Segments 27 divided. The soft magnetic elements 35 with recesses 35 'have the task of designing the resulting multipole axial field in such a way that the induction in the

The area of the sensors 24, 25 is sinusoidal. The period of the cutouts 35 ′ therefore corresponds to the period of the magnetization of the magnetic ring 30 or 33.

The magnetizable sensor ring 26 is in turn in the axial direction, i.e. Axial recesses 35 'extending parallel to the line of symmetry of the electrical induction machine 1. In addition to the illustration shown in FIG. 1 of a fixed, internal receiving element 23 with externally attached sensor elements 24 and 25 with an outer circumferential sensor ring 26, it would also be conceivable to provide a fixed, external receiving element 23, with internally attached sensor elements 24 and 25 in combination with an inner circumferential sensor ring 26. Furthermore, design variants would be conceivable for an end arrangement, with an arrangement rotated by 90 °. In addition, rotations of the arrangements are conceivable that comprise more or less than 90 °, so that the sensor elements 24, 25 are each received on a conical jacket.

A detailed view of the circumference of the sensor element recorded can be seen from FIG. 1.3 shown on an enlarged scale.

The annular receiving element 23, which is held in a rotationally fixed manner around the hollow housing shaft 13, comprises two sensor elements 24, 25 which are offset electrically from one another by exactly 1/4 of the magnetization pole pitch (corresponding to 90 °, τ = 1 = 360 °), of which according to FIG Representation in Figure 1.3 only one is shown. The setting 30 of the magnetic induction is identified by reference numeral 30, which leads to alternating magnetization of a sensor 24, for example a magnetoresistive sensor element, and influences the electrical resistance of the sensor element 24, provided that it is a magnetoresistive sensor element. The magnetic lines emanating from the stray field of the electrical induction machine 1 are preferably received by an annularly configured shielding element 28, which surrounds the magnetizable sensor ring 26. The course 30 or 33 of the magnetic induction from N to S that forms in the sensor ring is shown in more detail in FIG. The lines that characterize the course of the magnetic induction run in opposite directions (see illustration according to FIG. 3.2).

According to the representation in FIG. 2, the magnetizable sensor ring 26, which is fastened on the inside of the rotor carrier 12 rotating around the receiving element 23, is divided into individual segments 27. The segment division (compare illustration according to FIG. 3.1) is designated by reference number 31. The individual segments 27 of the segmented magnetizable sensor ring 26 are divided by recesses 35 'extending in the axial direction. Instead of a magnetizable sensor ring 26, which is divided into individual segments 27, a monolithic magnetic ring can be magnetized alternately.

FIG. 3.1 shows a segment-by-segment magnetizable sensor ring with a course of magnetic induction (Bsz) to be detected by the sensor elements.

From the view in Figure 3.1 gεht seen that the magnetoresistive as sensor elements 24 and 25 functioning sensors each other tisierungspolteilung is exactly 1/4 of the Aufmagne- τ (corresponding to 90 °) electrically offset ^'are to each other. The angular distance 32 preferably corresponds to exactly a quarter of the pole pitch 31. The pole pitch 31 of the magnetic sensor ring 26, ie the arrangement of N segments 27 or S segments 27 preferably corresponds to the number of pole pairs of the electric induction machine 1. The magnetization of the magnetizable sensor rings is so coordinated, • that the induction curve 30 in the gap between the inside of the magnetizable sensor ring 26 and the outside of the receiving element fixed to the housing, which receives the sensor elements 24 and 25, is as homogeneous as possible in the axial direction. If the polarity is changed, the induction changes periodically approximately preferably sinusoidally with the rotational movements of the movable rotating components, ie the segmented sensor ring 26 received on the inner wall of the motor mount 12. The course becomes through the ferromagnetic yoke elements 29, which include the recesses 35 ' the axial component of the induction, for which purpose in particular the ferromagnetic edge elements 29 are used. The course 30 of the magnetic induction Bsz can be achieved by appropriate adjustment of the geometrical shape of these recesses 35 'extending in the axial direction in coordination with the field of the sensor elements 24 and 25, so that the resulting analog signals of the sensor elements 24 designed as magnetoresistive sensors, for example or 25 have a sinusoidal profile 37. The sine functions of the two magnetoresistive sensor elements 24 and 25 are shifted by an electrical angle of 90 °. Analog signals can be calculated from the resulting voltages of the sensor elements 24 and 25, which represent the signal curve, with which a precise position description of the angular position of the rotor 14 within a pole pitch 31 is possible.

From the illustration according to FIG. 3.2, an enlarged representation of a segment from a segmentally magnetizable sensor ring is shown in greater detail.

From this representation it can be seen that the magnetizable sensor ring 26 is divided into individual segments 27 in a pole pitch 31. The course of the magnetic induction is identified by reference numeral 36, which is slightly delayed in the angular position of the individual segments 27 in the direction of the extension (compare position of the zero crossings 38 with respect to the beginning of the segment). The course of the induction in the individual segments 27 of the magnetizable sensor ring 26 causes alternating magnetization on the sensor elements 24 and 25, for example, as magnetoresistive sensor elements (not shown here). This results in an induction vector curve into the plane of the character or out of the plane of the character (see illustration according to FIG. 3.2).

By designing the axial recesses 35 in coordination with the magnetic field of the sensor elements, the desired course of the magnetic induction can be set, so that the resulting analog output signals of the magnetoresistive sensors 24 and 25 also have a sinusoidal course. From the resulting voltages of the sensors procured as magnetoresistive sensor elements, it is possible to determine two analog signals with which an exact position description, i.e. a precise detection of the winch cellage of the rotor 14 within a pole pitch is possible. These signals can be used to determine the electronic commutation of the electrical induction machine 1 and can be used as a basis for setting a reference curve in the current control.

In a further embodiment variant of the device proposed according to the invention for detecting the rotational position of a rotor of an electric rotating field machine 1, linearly operating Hall sensors can also be used instead of the magnetoresistive sensor elements 24 or 25 used. The configuration proposed according to the invention can thus also be operated with Hall sensors, in which two sensor signals "Sin" and "Cos" can also be used. LIST OF REFERENCE NUMBERS

I electrical rotary field machine 2 housing closure part

3 housing output

5 spindle

6 bearing journals 7 bearing bodies

8 spindle sleeve ε

9 thrust bearings

10 radial bearings

I I radial bearing 12 rotor carrier

13 housing hollow shaft

14 rotor

15 stands

16 winding 17 winding connections

18 engine air gap

19 engine mounts

20 rolling elements

21 bearing outer ring 22 inner bearing ring

23 receiving element

24 First sensor element

25 Second sensor element

26 Magnetizable sensor ring 27 Magnetic pole

28 shielding ring

29 Fenomagnetic yoke element

30 Magnetic induction

31 Poi division 32 angular distance

33 Induction curve

34 Yoke division

35 Axial recess Recess curve sinusoidal induction curve shifted zero crossing

Claims

Patentansprüebe

1. A method for detecting the rotational position on an electrical rotary field machine (1) which is electronically commutable, with a rotor carrier (12) accommodating a rotor (22) and a stator winding (15, 16) arranged in a rotationally fixed manner within a housing (3), characterized in that that

a magnetizable ring element (26) is assigned to the rotor carrier (12), - rotationally fixed sensor elements (24, 25) are provided, which the

Detect the course of the magnetic induction (30 or 33) and generate signal curves (36) of both sensor elements (24 or 25) shifted by an electrical angle from the periodic remagnetization of the sensor element (24 or 25).

2. Vεrfahrεn according to claim 1, characterized in that the course of the magnetic induction (30, 33) in the annular gap between the magnetizable ring elements (26) and the sensor elements (24, 25) periodically with rσtatorischen Movement of the ro tatar components (12, 26) changes.

3. The method according to claim 1, characterized in that the course of the magnetic induction (30, 33) changes sinusoidally.

4. The method according to claim 1, characterized gekennzεichnet that by the shape of recesses (35) and the repeat repetition of the recesses (35) in the magnetizable ring element (26) from the sensor elements (24, 25) generated analog signals have a sinusoidal profile.

5. The method according to claim 1 _5, characterized in that from the voltages of the sensor elements (24, 25) presenting the signal profile, two analog signals are generated which allow the exact determination of the rotational position of the rotor carrier (12) of the electrical rotary machine (1) and which are used for eiεktro is commutation of the electrical induction machine (1).

6. Device for detecting the rotational position on an electrical rotating field machine (1), which can be electronically commutated, with a rotor carrier (12) receiving a rotor (22) and a stator winding (15, 16) arranged in a rotationally fixed manner within a housing (3), thereby characterized in that the rotor support (12) has a Sem rotating, magnetizable ring element (26) is assigned, which is non-rotatably received on the housing (3) and rotates around sensor elements (24, 25) received approximately opposite one another.

7. The device according to claim 6, characterized in that the sensor elements (24, 25) are designed as linear Hall sensors.

8. The device according to claim 6, characterized gekennzeichnεt that the magnetic ring element (26) is designed as a magnetizable in segments (27) sensor ring.

9. The device according spoke 6, characterized gekεnnzεichnεt that diε Sεnsorelemente (24, 25) are designed as magneto-resistive sensors.

10. The device according spoke 8, characterized gekεnnzei chnet that the sensor elements (24, 25) in a fraction of a pole pitch (31) of the segmented Sεnsor- ring (26) corresponding to the angular position (32) are received.

11. The device according to claim 8, characterized in that the pole pitch (31) of the segmented sensor rings (26) corresponds to the yoke pitch (34) of fenomagnetic yoke elements (29).

12. The apparatus according to claim 6, characterized in that between the magnetizable ring element (26) and the rotor support (12), a shielding ring (28) • is received, in which diε magnetic lines of the stray field of the elεktrischεn rotating field machine (1) concentrate.