SENSOR SYSTEM AND METHOD FOR OPERATING A SENSOR SYSTEM

Abstract

A sensor system having a distance sensor (1) for detecting the distance between two objects (3,4) that can be moved relative to one another and having a magnetic field sensor (2) for detecting a magnetic field between the objects (3,4), in particular for detecting a gap width and a magnetic field between a rotor and a stator, and having a selection device (13), wherein a measurement signal from the distance sensor (1) or a measurement signal from the magnetic field sensor (2) can be supplied for further processing via the selection device (13). Furthermore, a method for operating a sensor system is described.

Claims

1. A sensor system comprising: a distance sensor (1) for detecting the distance between two objects (3,4) that can be moved relative to one another, a magnetic field sensor (2) for detecting a magnetic field between the objects (3,4) and a selection device (13), wherein, a measurement signal from the distance sensor (1) or a measurement signal from the magnetic field sensor (2) can be supplied for further processing via the selection device (13).

2. The sensor system according to claim 1, wherein the distance sensor (1) is a capacitive distance sensor or an inductive distance sensor or an optical distance sensor or an eddy-current sensor.

3. The sensor system according to claim 1, wherein the magnetic field sensor (2) is a flux sensor or a Hall-effect sensor or a magnetoresistive sensor (MR sensor

4. The sensor system according to claim 1, wherein the magnetic field sensor (2) has one or more conductor loops (8).

5. The sensor system according to claim 1, wherein the selection device (13) has a multiplexer (13).

6. The sensor system according claim 1, further comprising at least one of: a preamplifier (12) i& arranged between the selection device (13) and the distance sensor (1), and a preamplifier (12′) is arranged between the selection device (13) and the magnetic field sensor (2).

7. The sensor system according claim 1, further comprising at least one of: an analog/digital converter (14), preferably only a single analog/digital converter (14), and a computer (15).

8. The sensor system according to claim 1, further comprising at least one temperature sensor (17) for detecting the temperature in the region between the moveable objects (3,4).

9. The sensor system according to claim 1, wherein the distance sensor (1) and the magnetic field sensor (2) are arranged on a common substrate (10) with at least one of: the temperature sensor (17), the selection device (13), an analog/digital converter (14), and a computer (15).

10. The sensor system according to claim 1 wherein the distance sensor (1) and the magnetic field sensor (2) are arranged next to one another on a common substrate (10) or distance sensor (1) and the magnetic field sensor (2) are arranged one behind the other or one above the other in or on different layers of a multilayer substrate (10).

11. The sensor system according to claim 1, wherein a position sensor (16) is arranged to determine the position of the first component (3) relative to the second component (4).

12. A method for operating a sensor system, comprising: having a distance sensor (1) for detecting the distance between two objects (3,4) that can be moved relative to one another using a distance sensor (1), detecting a magnetic field between the objects (3,4) using a magnetic field sensor (2), and wherein, a measurement signal from the distance sensor (1) or a measurement signal from the magnetic field sensor (2) is supplied for further processing via a selection device (13).

13. The method according to claim 12, wherein the position of the first component (3) relative to the second component (4) is determined via a position sensor (16).

14. The method according to claim 13, wherein a spatial assignment of the detected distance and/or the detected magnetic field takes place taking into account the position detected by the position sensor (16).

15. The method according to claim 12, wherein the distance values and the magnetic field strength values are evaluated separately from one another in terms of time and/or space.

16. The method according to claim 12, wherein the distance values and the magnetic field strength values are offset against one another in such a way that a distance dependency of the magnetic field strength detection is compensated.

17. The sensor system according to claim 1, wherein the magnetic field sensor (2) detects a gap width and a magnetic field between a rotor and a stator.

18. The sensor system according to claim 3 wherein the magnetic field sensor (2) is a one of: an anisotropic magnetoresistive sensor (AMR sensor); and a giant magnetoresistive (GMR) sensor.

19. The sensor system according to claim 11, wherein the position sensor (16) is arranged to determine one of: an angle of rotation between a stator and a rotor; and a relative position between a rotor and a stator.

20. The method according to claim 12, wherein detecting a magnetic field between the objects (3,4) comprises measuring a gap width and a magnetic field between a rotor and a stator.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0030] FIG. 1 a schematic diagram of an exemplary embodiment of a sensor system according to the disclosure;

[0031] FIG. 2 a schematic diagram of the arrangement of a sensor system according to the disclosure on the components to be monitored;

[0032] FIG. 3 a further schematic diagram of the arrangement of the sensor system according to the disclosure on the components to be monitored;

[0033] FIG. 4 a schematic diagram of an exemplary embodiment of a distance sensor and a magnetic field sensor of a sensor system according to the disclosure;

[0034] FIG. 5 a schematic diagram of an exemplary embodiment of the electronics of a sensor system according to the disclosure, which are required for processing the measurement signals;

[0035] FIG. 6 a schematic diagram of a further exemplary embodiment of the electronics of a sensor system according to the disclosure, which are required for processing the measurement signals;

[0036] FIG. 7 a schematic diagram of an exemplary embodiment of the electronics of a sensor system according to the disclosure, which are required for processing the measurement signals; and

[0037] FIG. 8 a schematic diagram of an exemplary embodiment of the electronics of a sensor system according to the disclosure, which are required for processing the measurement signals.

DETAILED DESCRIPTION OF THE DISCLOSURE

[0038] In addition to the sensor system according to the disclosure, the method according to the disclosure is also explained with reference to the figures. FIG. 1 shows a sensor system for detecting geometric and magnetic variables, namely a distance sensor 1 and a magnetic field sensor 2, which are arranged in a common housing 18. The distance sensor 1, for example a capacitive distance sensor 1, measures the distance between the first object 3 and the second object 4 in the gap 5. The first object 3 is a rotor and the second object 4 is a stator of an electric motor 6 (cf. FIG. 2). In addition to an electric motor, this can be any other arrangement that has a rotor and a stator or even a linear drive. FIGS. 2, 3 clearly show that several pairs of distance sensor 1 and magnetic field sensor 2 are arranged about the rotor 3 or the stator 4.

[0039] FIG. 4 shows the structure of an exemplary sensor system. In the simplest case, the capacitive distance sensor 1 is implemented by a measuring electrode 7, the shape of which can be adapted to the geometric requirements. Instead of a capacitive distance sensor 1, other types of distance sensors, for example inductive, optical, or eddy-current sensors, could also be used. Furthermore, the measuring electrode 7 is shown in FIG. 4.

[0040] In the simplest case, the magnetic field sensor 2 is a flux sensor that detects the magnetic flux in the gap 5. It consists of at least one conductor loop 8 forming a coil 9. The coil 9 lies in the plane of the substrate 10 and, with a corresponding arrangement of the substrate 10 in the gap 5, almost perpendicular to the magnetic field lines.

[0041] The distance sensor 1 and the magnetic field sensor 2 are arranged in or on a common substrate 10. This can be a printed circuit board or a ceramic substrate, for example. For example, the capacitive distance sensor 1 is surrounded by the coil 9. Due to the concentric arrangement, the two measured variables are detected at the same point. However, the distance sensor 1 and magnetic field sensor 2 could also be arranged next to one another. As a very practical solution, the sensors can also be installed one behind the other on a common element.

[0042] By combining the distance sensor 1 and magnetic field sensor 2 in a common housing or on a common substrate 10, a common line 11 can be arranged.

[0043] In the simplest design, the substrate 10 has a single layer. The distance sensor 1 and the magnetic field sensor 2 are then arranged in a common plane. In one manner, the substrate 10 is multi-layered, i.e. a multi-layer printed circuit board or a multi-layer ceramic, in particular using LTCC technology. An arrangement on different levels of the substrate 10 would thus also be possible, wherein the distance sensor 1 and the magnetic field sensor 2 can be arranged offset from one another or also one behind the other. Due to the multi-layer arrangement, the coil 9 can also have a multi-layer design, as shown in FIG. 3. In this way, sufficiently high inductance can be achieved without expanding the surface area of the coil 9 too much.

[0044] FIG. 3 also shows that a position sensor 16 is arranged, which is used to determine an angle of rotation between the first object 3 (stator) and the second object 4 (rotor).

[0045] The electronics required for processing the measurement signals are shown in FIGS. 5 to 8. Accordingly, the electronics can likewise be arranged on the substrate 10. In the simplest case, the electronics only consist of signal pre-processing. This could be, for example, (analog) preamplifiers 12, 12′, which amplify the two signals so that they can be transmitted to the downstream electronics at a higher signal level. Filtering of the signals, for example using low-pass, high-pass, or band-pass filters, is also possible.

[0046] Digital processing of the signals as early as possible is advantageous. For this purpose, the electronics contain a selection device 13, preferably a multiplexer 13, and an analog/digital converter 14. The multiplexer 13, for example, has at least two inputs and one output. The distance signal is present at one input and the magnetic field signal at the second input. Initially, only the first input is switched through, so that the first signal (e.g. distance) is present at the analog/digital converter 14 and can be digitized. The second input is then switched through, so that the second signal (e.g. magnetic flux) is present at the analog/digital converter 14 and can be digitized. The two signals are then processed in a computer 15, for example a microcontroller.

[0047] The multiplexer 13 can be designed either as a separate component or as a component integrated into an analog/digital converter 14; both solutions can be implemented using standard components. The computer 15 can also be arranged on the substrate 10. Filtering can also be done digitally in the computer 15. Thus, the signals can be fully evaluated on the substrate 10.

[0048] It is also possible to place parts of the signal processing up to complete signal processing away from the substrate 10 in separate evaluation electronics. Only the most necessary components such as the distance sensor 1 and the magnetic field sensor 2 would then be contained on the substrate 10.

[0049] The two measurement signals can then be transmitted to the downstream evaluation electronics either via separate lines or via a common line 11. If an analog/digital converter 13 is used, the signals are then transmitted to the downstream electronics via a digital interface. The advantage of the digital interface is that it is immune to interference from the electromagnetic environment in the electric motor.

[0050] The evaluation of the signals can be carried out in the computer 15 by placing them in different relationships to one another depending on the requirements.

[0051] This includes mechanical variables such as air gap (min, max) across all individual poles or the eccentricity, conicity, and ovality of the rotor or stator and, for example, shaft displacement of the rotor due to bearing wear.

[0052] The magnetic field of individual poles can be measured as an essential electrical variable, which can even be compensated for in terms of distance by calculating the respective distance signals.

[0053] The exemplary embodiment shown in FIG. 7 corresponds to the exemplary embodiment from FIG. 5, wherein a temperature sensor 17 is also arranged. Furthermore, the exemplary embodiment according to FIG. 8 corresponds to the exemplary embodiment from FIG. 6, wherein a temperature sensor 17 is also arranged.

[0054] To avoid repetition with regard to further embodiments of the device according to the disclosure and the method according to the disclosure, reference is made to the general part of the description and to the appended claims.

[0055] Finally, it should be expressly noted that the above-described exemplary embodiments of the device according to the disclosure and of the method according to the disclosure are used solely to explain the claimed teaching, but do not restrict it to the exemplary embodiments.

LIST OF REFERENCE NUMERALS

[0056] 1 Distance sensor [0057] 2 Magnetic field sensor [0058] 3 First object [0059] 4 Second object [0060] 5 Gap [0061] 6 Electric motor [0062] 7 Measuring electrode [0063] 8 Conductor loop [0064] 9 Coil [0065] 10 Substrate [0066] 11 Line [0067] 12 Preamplifier [0068] 13 Selection device [0069] 14 Analog/digital converter [0070] 15 Computer [0071] 16 Position sensor [0072] 17 Temperature sensor [0073] 18 Housing