WO2008148698A1

WO2008148698A1 - Sensor array, measurement system, and measurement method

Info

Publication number: WO2008148698A1
Application number: PCT/EP2008/056631
Authority: WO
Inventors: Josef Janisch; Kurt RIEDMÜLLER
Original assignee: Austriamicrosystems Ag
Priority date: 2007-06-05
Filing date: 2008-05-29
Publication date: 2008-12-11
Also published as: DE102007026220B4; DE102007026220A1

Abstract

Disclosed is a sensor array for use with a magnetic source (MAG) that is magnetized in a sector-shaped manner and has a number of pairs of poles. Said sensor array comprises several magnetic field sensors (MS1-MS8) which are disposed along a circular circumference (CIR) and are each designed to emit a sensor signal (H1-H8) in accordance with a magnetic field intensity. A selection device that is coupled to the magnetic field sensors (MS1-MS8) is designed to derive, as a function of at least two sensor signals selected in accordance with the number of pairs of poles, a first and a second intermediate signal (OPP, ADJ) from the sensor signals (H1-H8) emitted by the magnetic field sensors (MS1 to MS8). The sensor array further comprises an evaluation device (EV) which is coupled to the selection device (SEL) and is designed to determine an angle of rotation (Φ) as a function of the first and second intermediate signal (OPP, ADJ) and the number of pairs of poles.

Description

description

Sensor arrangement, measuring system and measuring method

The invention relates to a sensor arrangement for use with a sector-shaped magnetized magnetic source, a measuring system and a measuring method.

Sensor arrays comprising magnetic field sensors for measuring a magnetic field intensity may be used to determine an angular deviation of a magnetic source with respect to the position or orientation of the magnetic field sensors. As magnetic sources are often used diametrically magnetized and rotatably mounted magnetic sources.

For example, the magnetic field sensors may be arranged along a circular circumference and provide over this circumference sensor signals which form approximately a sinusoidal curve, depending on the position and orientation of the magnetic source. In a diametrically magnetized magnet, for example, sensor signals from magnetic field sensors which are approximately at a right angle with respect to the circular circumference can be evaluated. In this way, based on the measured sensor signals, a rotation angle of the magnetic source can be determined within a full revolution of 360 °.

The angle of rotation thus determined is usually provided as a binary coded signal with a specific resolution. In some applications, however, it may be sufficient to determine a rotation angle of a magnetic source in a partial area of a full revolution, for example in an angular segment. However, since a determination of the angle of rotation is usually carried out with a resolution which relates to one full revolution, the relative resolution, based on the smaller angular range, is reduced. In other words, full digital resolution is not used in providing the digital angle value.

In order to increase the resolution of the sensor arrangement, for example, the number of magnetic field sensors can be increased. Alternatively, in order to adjust the relative resolution in an angular range to a resolution for a full revolution, a word width of the digitally provided one may also be used

Angle value can be increased. However, this increases the complexity of the sensor arrangement. Furthermore, such a customized sensor arrangement would each be set to a predetermined angular range.

The object of the invention is to specify a sensor arrangement and a measuring system with which a rotation angle of a magnetic source with high resolution can be determined. It is also an object of the invention to specify a measuring method with which a rotation angle of a magnetic source with high resolution can be determined.

This object is achieved with the subjects of the independent claims. Embodiments and further developments of the invention are the subject of the subclaims. An exemplary embodiment of a sensor assembly is provided for use with a sector-magnetized magnetic source having a number of pole pairs. The sensor arrangement comprises a first, a second, a third and a fourth magnetic field sensor, which are arranged along a circular circumference. The magnetic field sensors are each set up to emit a sensor signal as a function of a magnetic field intensity, which is brought about in particular by the sector-shaped magnetized magnet source. A selection device is coupled to the magnetic field sensors and configured to derive a first and a second intermediate signal as a function of at least two selected sensor signals from the sensor signals output by the magnetic field sensors. The at least two sensor signals are selected as a function of the number of pole pairs of the magnetic source. The sensor arrangement further has an evaluation device that is coupled to the selection device and configured to determine a rotation angle as a function of the first and second intermediate signal and the number of pole pairs.

By using a sector-shaped magnetized magnetic source, which has a certain number of pole pairs, that is, a certain number of pole pairs, the special configuration of the sensor array with respect to the magnetic field sensors and the choice of the output from the magnetic field sensor signals, an angle value or a rotation angle of the magnetic source for one of The pole pair number dependent angular range can be determined with high resolution. The pole pair number or a signal corresponding to the pole pair number can be supplied to the sensor arrangement, for example via a control input. For example, the magnetic field sensors are arranged in a circular segment along the circular circumference with a respective angular spacing of substantially 45 °. By appropriate selection and combination of the sensor signals emitted by the magnetic field sensors, a rotational angle of the respective magnetic source adapted to the respective number of pole pairs can be determined with the sensor arrangement for any desired magnetic sources, each with different pole pair numbers.

The sensor arrangement can be used both with a magnetic source having a pole pair number of 1, that is to say with a diametrically magnetized magnet, and with magnet sources having pole pair numbers greater than 1, which have more than two magnetic sectors. In the latter case, the sensor arrangement can be used to determine a rotation angle in an angular range determined by the number of pole pairs. The sensor arrangement can thus be adapted in a simple manner to different angular ranges or different pole pair numbers.

In a further embodiment, the sensor arrangement additionally has a fifth, a sixth, a seventh and an eighth magnetic field sensor which, together with the first, second, third and fourth magnetic field sensor, are arranged uniformly along the circular circumference. In other words, the first to eighth magnetic field sensors each have an inter-angle distance of substantially 45 °. The fifth to eighth magnetic field sensors are also set up to emit a sensor signal as a function of a magnetic field intensity. Accordingly, the selector is for deriving the first and second intermediate signals Also coupled with the fifth, sixth, seventh and eighth magnetic field sensor. Due to the further magnetic field sensors, the accuracy in determining the angle of rotation can be additionally improved for certain number of pole pairs.

In one exemplary embodiment of a measuring system, this comprises a set of at least four, for example, but also eight magnetic field sensors, which are arranged along a circular circumference and are each set up to emit a sensor signal as a function of a magnetic field intensity. Furthermore, a sector-shaped magnetized magnet source is provided in the system, which has a pole pair number and is rotatably mounted over the circular circumference. The measuring system further comprises a calculating means which is set up to select at least two sensor signals from the sensor signals emitted by the magnetic field sensors as a function of the number of pole pairs and to determine a rotational angle of the magnetic source as a function of the pole pair number and the at least two selected sensor signals. For example, the magnetic field sensors are arranged uniformly along the circular circumference.

In the measuring system, a rotation angle of the magnetic source can be determined with high accuracy in an angular range determined by the number of pole pairs.

The determination of the angle of rotation can take place in the sensor arrangement and in the measuring system by means of an angular function from the selected sensor signals or the intermediate signals. Furthermore, dividing means may be provided for dividing by the number of pole pairs for determining the angle of rotation. In one exemplary embodiment of the measuring method, a first, a second, a third and a fourth magnetic field sensor are provided, which are arranged along a circular circumference and each output a sensor signal as a function of a magnetic field intensity. Furthermore, a sector-shaped magnetized magnet source is provided, which has a pole pair number and is rotatably mounted over the circular circumference. Depending on the number of pole pairs, at least two sensor signals are selected from the emitted sensor signals. A rotation angle of the magnetic source is determined as a function of the selected sensor signals and the number of pole pairs.

The magnetic source with the number of pole pairs can be selected according to a desired angular range for which a rotation angle of the magnetic source is to be determined. Accordingly, corresponding to the selected number of pole pairs of the magnetic source corresponding sensor signals are selected by the magnetic field sensors for further processing. Thus, the rotation angle can be individually adjusted to the number of pole pairs with a high resolution. Compared to a diametrically magnetized magnetic source with a number of pole pairs of 1 results in a magnetic source having a Polpaarzahl greater than 1, at the same rotational speed, a sinusoidal course of the magnetic field intensity at one of the magnetic field sensors with a Polpaarzahl correspondingly higher frequency. In other words, a mechanical angle of rotation of the magnetic source in a pole pair number corresponding to higher electrical angle results in the magnetic field sensor. For example, the sensor signals are selected such that they have an electrical angular distance of substantially 90 ° to each other. By way of corresponding trigonometric relationships, the angle of rotation can be determined, for example, by means of an angle function, such as an inverse tangent or an arctangent function. Accordingly, it is also possible, for different pole pair numbers, to respectively determine or select those magnetic field sensors which are suitable for outputting sensor signals with the electrical angular spacing of substantially 90 °.

Also in the measuring method, for example, eight magnetic field sensors distributed uniformly over the circumference can be provided, the sensor signals of which can be used to determine the rotational angle.

In the following, the invention will be explained in more detail with reference to the drawings. Functionally or functionally identical elements bear the same reference numerals.

Show it:

FIG. 1 shows a first exemplary embodiment of a sensor arrangement,

FIG. 2 shows a second exemplary embodiment of a sensor arrangement,

FIG. 3 shows a third exemplary embodiment of a sensor arrangement, FIG. 4 shows an exemplary diagram with vectors of intermediate signals for calculating the angle of rotation,

FIG. 5 shows an exemplary diagram for profiles of sensor signals for different pole pair numbers,

6 shows a first embodiment of a magnetic source with correspondingly arranged magnetic field sensors and

Figure 7 shows a second embodiment of a magnetic source with correspondingly arranged magnetic field sensors.

FIG. 1 shows an exemplary embodiment of a sensor arrangement which can be used with a sector-shaped magnetized magnetic source (not shown here). In this exemplary embodiment, the sensor arrangement has a set of eight magnetic field sensors MS1 to MS8 and a selector SEL, which is coupled on the input side with the magnetic field sensors MS1 to MS8 and on the output side with an evaluation circuit EV. From the magnetic field sensors MS1 to MS8, which for example each have a Hall sensor, respective sensor signals H1 to H8 are emitted during operation, the value of which depends on a magnetic field intensity at the position of the magnetic field sensor.

The magnetic field sensors MS1 to MS8 are arranged uniformly along a circular circumference CIR, so that a respective intermediate angle between the magnetic field sensors is essentially 45 °. This is exemplified in the drawing, for example, for the angle between the seventh magnetic field sensor MS7 and the eighth magnetic field sensor MS8. provides. The circular circumference CIR or the arrangement of the magnetic field sensors MS1 to MS8 preferably form a non-curved plane.

The selector SEL has a control input CIN, via which a control word or control signal can be supplied, which expresses a pole pair number of the magnetic source to be used. The selection device SEL is set up to select at least two sensor signals from the sensor signals H1 to H8 output by the magnetic field sensors MS1 to MS8 and to derive from the selected sensor signals a first and a second intermediate signal OPP, ADJ which are output on the output side to the evaluation circuit EV. For example, the intermediate signals OPP, ADJ represent two vectors, which are substantially perpendicular to one another and whose sum form an angle to a reference coordinate system, from which a rotational angle Φ of a magnetic source used can be derived. This can be done, for example, via simple trigonometric functions such as, for example, an arctangent function. The rotation angle Φ is output at an output OUT.

In an operation of the sensor arrangement, the magnetic source, not shown here, is preferably mounted rotatably about the center of the circular circumference CIR and forms with the sensor arrangement a corresponding measuring system.

In a further embodiment, the fifth, sixth, seventh and eighth magnetic field sensors MS5 to MS8 may also be omitted, with the position of the first four magnetic field sensors MS1 to MS4 remaining unchanged. In this case too, depending on the number of pole pairs, Select chende sensor signals from the available sensor signals Hl to H4 to derive therefrom the intermediate signals OPP, ADJ.

Both in the embodiment with four magnetic field sensors MS1 to MS4 and with eight magnetic field sensors MS1 to MS8, the first and second intermediate signals OPP, ADJ can be derived by addition and / or subtraction of the selected sensor signals in the selection device.

FIG. 2 shows a further exemplary embodiment of a sensor arrangement for determining a rotation angle of a sector-magnetized magnet source. In this case, the selection device SEL comprises a differential amplifier or operational amplifier OP1 to OP8 for each of the eight magnetic field sensors MS1 to MS8. In the case of the operational amplifiers OP1 to 0P8, in each case a first input E +, which is a non-inverting input, is connected to a reference potential terminal GND. A respective second input E-, which accordingly is an inverting input, is coupled to an associated magnetic field sensor. Inverting and non-inverting input E-, E + of the operational amplifiers OP1 to 0P8 can also be interchanged in other embodiments. The arrangement of the magnetic field sensors MS1 to MS8 along the circular circumference CIR is not shown in this embodiment for reasons of clarity.

The operational amplifiers OP1 to 0P8 also each have a non-inverting and an inverting output 0+, O-, at which, for example, a positive or negative or inverted current can be delivered. Each of the outputs of the operational amplifiers OPl to 0P8 is ü One of the switches Sil to S84 is selectively coupled to a first and a second input AIN1, AIN2 of an analog-to-digital converter AD1. The switch position of the switches Sil to S84 is controlled by a control circuit CTL, which has the control input CIN. On the output side, the analog-to-digital converter AD1 is coupled to the evaluation circuit EV for the transmission of the first and second intermediate signals OPP, ADJ in digital form.

For example, the sensor signal of the first magnetic field sensor MS1, which is present as an analog current or voltage signal, can be amplified via the first operational amplifier OP1 to form a further analog current signal, which is present at the corresponding outputs O +, O- in inverted or non-inverted form. Accordingly, the inverted, amplified current signal can be supplied to the first input AIN1 of the analog-to-digital converter AD1 from the output 0- of the operational amplifier OP1 via the switch Sil. Alternatively, this current can also be supplied via the switch S12 to the second input AIN2. In the same

A current at the noninverting output O + of the operational amplifier OP1 can alternatively be routed via the switches S13, S14 to the first or the second input AIN1, AIN2 of the analog / digital converter AD1.

In other words, the amplified sensor signal can be applied to the first or the second input AIN1, AIN2 both in inverted and non-inverted form. However, it is also possible that all switches assigned to an operational amplifier, for example for the operational amplifier OP1, the switches Sil to S14, are switched to a nonconducting state and thus no speaking sensor signal, here the affected magnetic field sensor MSl, is given to the analog-to-digital converter ADl.

The mode of operation of the remaining switches S21 to S84 for the remaining operational amplifiers OP2 to OP8 corresponds to the above-described mode of operation. Thus, a summation of non-inverted and inverted sensor signals of the individual magnetic field sensors MS1 to MS8 can take place at the first and second inputs AIN1, AIN2 of the analog-to-digital converter AD1. In other words, due to the various switch positions of the switches S 1 to S 84, a respective addition and / or subtraction of the sensor signals can be carried out, wherein not all sensor signals have to be included in the respective result of the signal addition and subtraction.

Corresponding control signals for the control of the individual switches Sil to S84 can be derived from the control circuit CTL as a function of a signal at the control input CIN, which in a corresponding form comprises information about the pole pair number of a magnet used or intended for use. As already mentioned above, depending on the number of pole pairs, those magnetic field sensors are selected which have an angular distance of substantially 90 ° with respect to an electrical characteristic of a sinusoidal sensor signal, one of each for the first intermediate signal and the other for 90 ° ° shifted, used for the second intermediate signal.

Sensor signals from other magnetic field sensors, which have an electrical angular distance of substantially 180 ° aufwei- That which corresponds to an inversion of the corresponding sensor signal can just be used in accordance with this inverted sign inversion for the respective intermediate signal in order to increase the signal strength of the resulting intermediate signal. For example, therefore, the sensor signal of a first magnetic field sensor is used in non-inverted form for the derivation of the intermediate signal and the sensor signal of a second magnetic field sensor, which has an electrical angular distance of 180 ° to the first magnetic field sensor, in an inverted form.

The physical position of the magnetic field sensors MS1 to MS8, from which the sensor signals are output according to the electrical angular distance, depends on the pole pair number.

The embodiment of a sensor arrangement shown in FIG. 2 can in turn be used together with a corresponding magnetic source as the measuring system.

FIG. 3 shows a further exemplary embodiment of a sensor arrangement, which is similar in particular to the arrangement of the magnetic field sensors MS1 to MS8 of the sensor arrangement of FIG. In contrast to the embodiment in FIG. 1, in the exemplary embodiment in FIG. 3, the sensor signals H1 to H8 are fed to an analog-to-digital converter AD2, whose output is digitally coupled to the selector SEL.

The present as analog current or voltage signals

Sensor signals H1 to H8 are converted in the analog-to-digital converter AD2 into digital sensor signals, the analogue Digital conversion in various embodiments can be carried out both in parallel and in series. A combination of parallel and serial analog-to-digital conversion can also be implemented. Likewise, the digital sensor signals can be transmitted in serial or parallel form to the selector SEL. In parallel conversion or transmission higher processing speeds can be achieved and accordingly higher speeds of a magnetic source can be processed. However, serial conversion or transmission can reduce the circuit complexity. A corresponding embodiment depends on the respective requirements.

The selection device SEL is set up to derive the first and second intermediate signals OPP, ADJ from the digital sensor signals as a function of a control signal at the control input CIN and to output them to the evaluation circuit EV. In this case, an additional or subtractive combination of selected digital sensor signals can again be made in the selection device SEL in order to be able to derive the corresponding intermediate signals OPP, ADJ.

The exemplary embodiment of a sensor arrangement shown in FIG. 3 can also be used together with a sector-shaped magnetized magnet source in a measuring system for determining a rotation angle of the magnetic source.

As already mentioned, sinusoidal sensor signals, whose frequency depends inter alia on a rotational speed of a magnetic source used but also on the number of pole pairs, are produced at the magnetic field sensors MS1 to MS8. Since the first and second intermediate signals OPP, ADJ are selected from selected sensor signals of the available sensor signals Hl to H8 are derived, the intermediate signals OPP, ADJ preferably each have a sinusoidal shape. Because of the angular relationships, the respective values of the intermediate signals OPP, ADJ can be understood as amounts of mutually perpendicular vectors whose vector sum represents an electrical rotation angle of the magnetic source.

FIG. 4 shows an exemplary diagram with corresponding vectors of the intermediate signals OPP, ADJ. For reasons of clarity, the first intermediate signal OPP is drawn as a vector on the high-value axis or y-axis, while the second intermediate signal ADJ is drawn as a vector on the right-value axis or x-axis. The sum of the vectors OPP, ADJ results in a resultant vector RES whose angle φ to the right-hand value axis corresponds to the electrical angle of the generating magnetic source.

The angle φ can be determined from the first and second intermediate signal OPP, ADJ via simple angle functions. For example, between the angle φ and values opp, adj of the intermediate signals OPP, ADJ, which may also become negative, the relationship exists

opp tan φ = - adj _{f (1)}

so that the angle φ results

opp φ = arctan - a ^d ^. (2) From the thus determined angle φ, which can for example assume values of -180 ° to + 180 ° or from 0 ° to 360 ° in degree, the absolute mechanical angle of the magnetic source with respect to the circular arrangement of the magnetic field sensors MS1 to MS8 in Determine the dependence of the number of pole pairs. The angle φ can also be given in corresponding ranges in radians, -π to + π, or 0 to 2π.

For example, the absolute mechanical angle Φ is given by dividing the electrical angle φ by the number of pole pairs. Accordingly, no division would be necessary for a two-pole, diametrically magnetized magnet with a pole pair number of 1. For a four-pole magnet with a pole pair number of 2, the electrical angle value φ would have to be divided by 2 to obtain the rotation angle Φ of the magnetic source. For example, the evaluation circuit EV in one of the exemplary embodiments shown in FIGS. 1 to 3 has a dividing means which is intended to divide the electrically determined angle φ by the number of pole pairs.

FIG. 5 shows an exemplary signal diagram with sensor signals that can be generated by magnetic sources with different pole pair numbers. The angle values given at the top of the diagram correspond to a mechanical angle of rotation of the respective magnetic source.

The uppermost signal diagram represents the course of sensor signals for a diametrically magnetized, two-pole magnet with a corresponding number of pole pairs of 1. In this case, a mechanical angle of rotation corresponds to an electrical angle. rically determinable angle. In order to derive the first and second intermediate signals OPP, ADJ, in this case the sensor signals of the magnetic field sensors are used for one of the intermediate signals at the positions designated 0 ° and 180 °, denoted by sin for the positive component of the intermediate signal and -sin for the portion of the intermediate signal to be inverted. The second intermediate signal is determined from the sensor signals of the magnetic field sensors located at the positions designated by 90 ° and 270 °. As can be seen from the sinusoidal progressions shown in the diagram, these have an electrical angular distance of 90 ° to one another. Accordingly, for example, the corresponding angle value from the intermediate signals OPP, ADJ can be determined by the method described with reference to FIG. The positions of the magnetic field sensors of the sensor signal shifted by 90 ° are identified in this case by -cos and cos, wherein the position marked by -cos enters the second intermediate signal in an inverted form.

Optionally, only one of the respective sensor signals can be used in each case. However, by using two or four sensor signals to derive a respective intermediate signal, the signal quality of the intermediate signals can be improved. In particular, by the difference between a non-inverted and an inverted sensor signal, a DC component possibly contained in the sensor signals can be compensated or eliminated. Such a DC component can be generated, for example, by a third-order magnetic DC field which is essentially uniformly applied to all magnetic field sensors. ren acts and changes the magnetic field intensity generated by the rotatable magnetic source evenly.

The middle signal diagram shows a progression of the sensor signals for a four-pole magnet source with a pole pair number of 2. It can be seen that for this case an electrical angle of 90 ° corresponds to a mechanical rotation angle of the magnetic source of 45 °. Similar to the two-pole magnetic source described in the upper diagram, the first intermediate signal from the sensor signals of the magnetic field sensors, which are denoted by sin and -sin, can be derived, while the second intermediate signal from the sensor signals at the positions with cos and cos are indicated.

The lower signal diagram shows the course of sensor signals when using a six-pole sector-shaped magnetized magnet source with a number of pole pairs of 3. Accordingly, it follows again that the electrical angle of the number of pole pairs corresponding to, that is three times greater than the mechanical rotation angle of the magnetic source. In other words, the mechanical rotation angle is obtained by dividing the determined electrical rotation angle by the number of pole pairs of 3. Although the same magnetic field sensors or their sensor signals are used in comparison to the two-pole magnetic source, the derivative of the second intermediate signal, in each case reversely polarized sensor signals in comparison to bipolar magnetic source.

For the derivation of the intermediate signals OPP, ADJ, it is necessary to select respective sensor signals and correct sign, that is in inverted or not inverted tated form, to merge. The selector SEL according to one of the illustrated embodiments is in each case configured to make this selection and combination as a function of the number of pole pairs. With n as an integer value, the first and second intermediate signals OPP, ADJ can be determined, for example, according to Table 1 as a function of the number of pole pairs.

Table 1

Number of pole pairs Calculation of the intermediate signals OPP, ADJ

4n + l OPP = Hl - H5 ADJ = H3 - H7

4n + 3 OPP = Hl - H5 ADJ = -H3 + H7

8n + 2 OPP = Hl - H3 + H5 - - H7 ADJ = H2 - H4 + H6 - H8

8n + 6 OPP = Hl - H3 + H5 - - H7 ADJ = -H2 + H4 + H6 -h H8

The possibilities shown in Table 1 for deriving the first and second intermediate signals OPP, ADJ are not exclusive and may be replaced by other combinations of the sensor signals. In particular, fewer sensor signals can also be used to derive the intermediate signals OPP, ADJ, as explained above.

Accordingly, in one embodiment, the selector SEL may be arranged to derive the first and second odd pole pair number intermediate signals as a function of two or four sensor signals, the sensor signals being from that of the magnetic field sensors MSl are issued to MS8, which are arranged at a respective angular distance of substantially 90 °.

Accordingly, for an even pole pair number, the first and second intermediate signals OPP, ADJ may be derived as a function of two or four or eight sensor signals, the sensor signals being output from those of the magnetic field sensors MS1 to MS8 arranged at a respective angular distance of substantially 45 ° are.

Accordingly, the angle of rotation Φ can also be determined as a function of the dependencies just described.

The number of pole pairs or poles of the magnetic source can theoretically be arbitrarily increased. However, it may be necessary to limit the number of poles of the magnetic source such that a distance of adjacent poles of the magnetic source along the circular circumference CIR is not smaller than a distance between the magnetic source per se and the circular arrangement of the magnetic field sensors. FIGS. 6 and 7 show exemplary embodiments of sector-shaped magnetized magnet sources MAG and corresponding magnetic field sensors, which are each used to derive the intermediate signals OPP, ADJ.

With reference to FIG. 5, in particular the middle diagram, FIG. 6 shows that a positive component for the first intermediate signal emerges from the magnetic field sensors MS1 and MS5, characterized by the inscription sin. The corresponding negative sensor signals which are to be inverted for the first intermediate signal are derived from the mag- from field sensors MS3 and MS7, accordingly characterized by -sin.

The second intermediate signal results from the non-inverted sensor signals of the magnetic field sensors MS2 and MS6 and from the inverted sensor signals of the magnetic field sensors MS4 and MS8, characterized by cos or -cos.

The illustration also shows that the sensor signals of the magnetic field sensors MS4, MS5, MS6, MS7 could also be discarded for a calculation of the rotation angle. However, their use can improve the signal quality of the intermediate signals OPP, ADJ.

FIG. 7 shows an arrangement with a six-pole magnetic source MAG and corresponding magnetic field sensors MS1, MS3, MS5, MS7, whose sensor signals are used to derive the first and second intermediate signals OPP, ADJ. The arrangement or selection of the corresponding magnetic field sensors essentially corresponds to the principle illustrated in FIG. 5 for the lower diagram.

In various embodiments, with appropriate evaluation of the determined angle of rotation for Polpaarzahlen greater than 1, a speed of an associated with the magnetic source arrangement can be determined with higher accuracy. This results from the fact that a corresponding higher number of zero crossings in the angle value of the rotational angle Φ can be detected for an increased number of pole pairs.

A sensor arrangement according to one of the described exemplary embodiments can be easily adapted for different magazines. Net sources are produced with different Polpaarzahlen, without knowing from the outset the ultimate pole pair number of the magnetic source, since it can be set in a simple manner when commissioning the sensor array with a magnetic net source.

In various embodiments, the evaluation device EV or the calculating means is set up to output the electrical angle instead of the mechanical angle of rotation, which can result from dividing by the number of pole pairs. However, the dependence of the electrical angle and the mechanical angle on the number of pole pairs remains unchanged and can be taken into account in subsequent circuits which are connected to the output OUT, if appropriate.

If the rotation angle φ is output, for example, as a binary data word, the significance of one bit of the binary data word can be adjusted as a function of the number of pole pairs of the magnet used in a downstream arrangement, so that the resolution of the binary data word is refined with the number of pole pairs.

In further embodiments, a higher number of magnetic field sensors, for example 16 magnetic field sensors, may also be used, which are arranged uniformly along the circular circumference. This may result in further combination possibilities for the derivation of the first and second intermediate signal.

Claims

claims

A sensor arrangement for use with a sector-magnetized magnet source (MAG) having a pole pair number, the sensor arrangement comprising first, second, third and fourth magnetic field sensors (MS1, MS2, MS3, MS4) arranged along a circular circumference (CIR) are arranged and are each arranged to emit a sensor signal (Hl, H2, H3, H4) as a function of a magnetic field intensity; a selection device (SEL) coupled to the magnetic field sensors (MS1, MS2, MS3, MS4) and arranged to derive a first and a second intermediate signal (OPP, ADJ) as a function of at least two selected sensor signals from those of the magnetic field sensors ( MSl, MS2, MS3, MS4) emitted sensor signals (Hl, H2, H3, H4), the at least two sensor signals selected as a function of the number of pole pairs; and an evaluation device (EV) coupled to the selector (SEL) and configured to determine a rotation angle (Φ) as a function of the first and second intermediate signals (OPP, ADJ) and the number of pole pairs.

2. Sensor arrangement according to claim 1, wherein the magnetic field sensors (MSl, MS2, MS3, MS4) are arranged in a circular segment along the circular circumference (CIR) with a respective angular distance of substantially 45 °.

3. Sensor arrangement according to claim 1 or 2, wherein the evaluation device (EV) with the selection device (SEL) via at least one analog-to-digital converter (ADl) is coupled.

4. Sensor arrangement according to claim 1 or 2, - having at least one analog-to-digital converter (AD2), which is adapted to convert the sensor signals, which are present as analog current or voltage signals, into digital sensor signals; and wherein the selector (SEL) is arranged to derive the first and second intermediate signals (OPP, ADJ) as digital signals from the digital sensor signals.

5. Sensor arrangement according to one of claims 1 to 4, wherein the selection means (SEL) is adapted to derive the first and second intermediate signal (OPP, ADJ) by adding and / or subtracting the selected sensor signals.

6. Sensor arrangement according to one of claims 1 to 5, wherein the evaluation device (EV) is adapted to determine the rotation angle (Φ) by means of an angular function of the first and second intermediate signal (OPP, ADJ).

7. Sensor arrangement according to one of claims 1 to 6, wherein the evaluation device (EV) has a dividing means for dividing by the number of pole pairs.

8. Sensor arrangement according to one of claims 1 to 7, comprising a fifth, a sixth, a seventh and an eighth magnetic field sensor (MS5, MS6, MS7, MS8), which together with the first, second, third and fourth magnetic field sensor (MSL, MS2 , MS3, MS4) evenly along the circular circumference (CIR) are arranged and each adapted to emit a sensor signal (H5, H6, H7, H8) in response to a magnetic field intensity; and wherein the selector (SEL) for deriving the first and second intermediate signals (OPP, ADJ) is also coupled to the fifth, sixth, seventh and eighth magnetic field sensors (MS5, MS6, MS7, MS8).

9. Sensor arrangement according to claim 8, wherein the selection device (SEL) is arranged to derive the first and second intermediate signal (OPP, ADJ) such that for an odd pole pair number the first and second intermediate signal (OPP, ADJ) as a function of two or four sensor signals are derived, the sensor signals being emitted by those of the magnetic field sensors (MS1 - MS8), which are arranged at a respective angular spacing of substantially 90 °; and for an even number of pole pairs, the first and second intermediate signals (OPP, ADJ) are derived as a function of two or four or eight sensor signals, the sensor signals being emitted by those of the magnetic field sensors (MS1 - MS8) which are at a respective angular distance of are arranged substantially 45 °.

10. Sensor arrangement according to one of claims 1 to 9, wherein at least one of the magnetic field sensors (MSl - MS8) comprises a Hall sensor.

11. Measuring system comprising a set of at least four magnetic field sensors (MS1-MS8) arranged along a circular circumference (CIR). are net and are each set up to emit a sensor signal (Hl - H8) as a function of a magnetic field intensity; a sector-shaped magnetized magnetic source (MAG) having a pole pair number and rotatably supported over the circular periphery (CIR); and a calculation means (SEL, EV) which is set up to select at least two sensor signals from the sensor signals (Hl-H8) emitted by the magnetic field sensors (MS1-MS8) as a function of the number of pole pairs and a rotation angle (Φ) of the magnetic source (MAG ) as a function of the number of pole pairs and the at least two selected sensor signals.

12. A measuring system according to claim 11, wherein the computation means (SEL, EV) comprises at least one analog-to-digital converter (AD1, AD2), which is arranged to convert the sensor signals (Hl - H8), which are current or Voltage signals are present in digital sensor signals; and - is arranged to determine the angle of rotation (Φ) from the digital sensor signals.

13. A measuring system according to claim 11 or 12, wherein the calculating means (SEL, EV) is adapted to determine the rotation angle (Φ) by means of an angular function of the selected sensor signals.

14. A measuring system according to any one of claims 11 to 13, wherein the calculating means (SEL, EV) is adapted to determine the rotation angle (Φ) for an odd pole pair as a function of two or four sensor signals, wherein the sensor signals of those of the magnetic field sensors (MS1 - MS8) are delivered, which are arranged at a respective angular distance of substantially 90 °; and to determine for an even number of pole pairs as a function of two or four or eight sensor signals, wherein the sensor signals are emitted by those of the magnetic field sensors (MS1 - MS8), which are arranged at a respective angular spacing of substantially 45 °.

15. Measuring method, comprising

Providing a first, a second, a third and a fourth magnetic field sensor (MS1, MS2, MS3, MS4), which are arranged along a circular circumference (CIR) and in each case a sensor signal (H1, H2, H3, H4) as a function of a give magnetic field intensity;

Providing a sector magnetized magnet source (MAG) having a pole pair number and being rotatably mounted over the circular periphery (CIR);

Selecting at least two sensor signals from the sensor signals (H1, H2, H3, H4) output by the magnetic field sensors (MS1, MS2, MS3, MS4) as a function of the number of pole pairs; and

Determining a rotation angle (Φ) of the magnetic source (MAG) as a function of the selected sensor signals and the pole pair number.

16. The measuring method according to claim 15, wherein at least the selected sensor signals are converted analog-digitally before the determination of the angle of rotation (Φ).

17. The measuring method according to claim 15 or 16, wherein determining the angle of rotation (Φ) comprises: Deriving a first and a second intermediate signal (OPP, ADJ) by adding and / or subtracting the selected sensor signals; and

Determining the angle of rotation (Φ) by means of a Winkelfunk- tion from the first and second intermediate signal (OPP, ADJ).

18. The measuring method according to claim 15, further comprising providing fifth, sixth, seventh and eighth magnetic field sensors (MS5, MS6, MS7, MS8) in common with said first, second, third and fourth magnetic field sensors (MSl, MS2, MS3, MS4) are arranged uniformly along the circular circumference (CIR) and each adapted to emit a sensor signal (H5, H6, H7, H8) in response to a magnetic field intensity, wherein the selection of the sensor signals also from the sensor signals emitted by the fifth, sixth, seventh and eighth magnetic field sensor (MS5, MS6, MS7, MS8).

19. The measuring method according to claim 18, wherein, when determining the angle of rotation (Φ), the angle of rotation (Φ) for an odd pole pair number is determined as a function of two or four sensor signals, the sensor signals being emitted by those of the magnetic field sensors (MS1-MS8), which are arranged at a respective angular distance of substantially 90 °; and is determined for an even number of pole pairs as a function of two or four or eight sensor signals, the sensor signals being emitted by those of the magnetic field sensors (MS1-MS8) arranged at a respective angular spacing of substantially 45 °.