SENSOR SYSTEM FOR DETERMINING AT LEAST ONE ROTATIONAL PROPERTY OF A ROTATING ELEMENT

Description

State of the art

[0001] Numerous sensors are known from the prior art that detect at least one rotational property of rotating elements. Examples of such sensors are described in Konrad Reif (ed.): Sensors in Motor Vehicles, 2nd edition, 2012, pages 63-74 and 120-129. For example, the position of a camshaft of an internal combustion engine relative to a crankshaft can be determined with a phase sensor using a Hall sensor.

[0002] For example, to implement traction in electric vehicles, either asynchronous or synchronous machines are often used, each consisting of a stationary stator and a rotating rotor. The stator usually has three winding phases offset from each other by, for example, 120° / p, where p represents a number of pole pairs. In asynchronous machines, the rotor usually consists of electrically conductive bars with their ends short-circuited in a ring. When a rotor field rotates, a voltage can be induced in the bars, causing a current to flow, which in turn builds up a counter magnetic field and results in a rotational movement. The induced voltage is zero when the rotor field and stator rotate at the same speed. A speed difference arises, which is referred to as slip and which defines the motor torque.In synchronous machines, the rotor comprises a rotor carrying an excitation coil through which a direct current flows and generates a static magnetic field. Alternatively, a permanent magnet can be used as the rotor. This is then a permanently excited synchronous machine, which has a higher efficiency due to the powerless excitation and can therefore be more suitable for traction applications. In principle, the rotor speed can be identical to the speed of an excitation field. The torque can depend on a phase shift, i.e. an angular difference between the stator field and the rotor. To control the torque, control an inverter, and accordingly provide stator coil signals, the rotor speed must be known for asynchronous machines and the absolute angular position of the rotor for synchronous machines.

[0003] To determine these variables, a so-called resolver is often used. This is usually an electromagnetic measuring transducer in which a rotor core is mounted on the motor shaft at a fixed speed. An excitation coil and two receiving coils are mounted in a circular ring on a stator. The excitation coil is supplied with an alternating voltage signal and permeates the entire arrangement with an alternating electromagnetic field. Depending on the angle of rotation, a sinusoidal amplitude-modulated voltage is induced in the first receiving coil, while a cosinusoidal amplitude-modulated voltage is induced in the second receiving coil. The complete provision of the excitation signal and the readout of the signals are realized within the power electronics or dedicated components within the control unit for motor control.This makes the resolver, in and of itself, a purely passive component and, by definition, ASIL D compliant (ASIL: Automotive Safety Integrity Level). ASIL capability, which is classified using the letters A to D, is a quantitative value that indicates the proportion of undesired operating states of the sensor that are detected, such as short circuits, coil interruptions, implausible signals, or similar operating states. However, the resolver generally requires a relatively large amount of installation space, entails complex signal provision and signal conditioning, and must generally be mounted with very tight mechanical tolerances to achieve sufficiently high accuracy. For these reasons, the system costs are correspondingly high.In addition to electromagnetic resolvers, there are also optical resolvers, as described, for example, in DE 10 2013 203 937 A1, which, however, in addition to being expensive, are generally cross-sensitive to contamination and therefore cannot be used in every environment.

[0004] Alternatively, inductive absolute angle sensors based on coupled coils can also be used, as described, for example, in DE 10 2016 202 877 B3. This describes a rotation angle sensor comprising a stator element with a transmitting coil and at least two receiving coils arranged within the transmitting coil and arranged on a circuit board. The rotation angle sensor further comprises a rotor element rotatably mounted about a rotation axis with respect to the stator element, via which rotor element the transmitting coil is inductively coupled to the at least two receiving coils, such that the inductive coupling depends on a rotation angle between the stator element and the rotor element, and the transmitting coil induces at least two angle-dependent alternating voltages in the at least two receiving coils.The rotor element and the at least two receiving coils are designed in such a way that an alternating voltage is induced in the receiving coils, the amplitude of which is sinusoidally dependent on the angle of rotation. A technical challenge typically arises from the fact that, due to the high frequency, the provision of the excitation signal and the evaluation of the receiving coil signals can often no longer be implemented in the control unit to implement the sensor function. Therefore, an ASIC for the sensor electronics is generally required, which is placed directly on the circuit board that also carries the coil structures. In addition to the actual sensor function, this ASIC must often also implement a high level of diagnostics, for example, detecting shunts and monitoring the frequency / amplitude of the excitation signal.To achieve ASIL D capability, two ASICs with at least one separate receiver coil system are often used, and both angle signals from the control unit are compared. This increases the cost of the electronics and the complexity of the supply lines. Furthermore, so-called common-cause errors—systematic errors in the ASIC design that can occur simultaneously in both ASICs—pose a challenge.

[0005] In order to achieve a high ASIL classification and to exclude common-cause errors, two diverse sensor concepts can also be used.

[0006] Here, for example, it is common to use magnetic field-based angle sensors. For this purpose, a magnet is attached to a rotor that rotates relative to a magnetic field sensor assumed to be stationary. In the simplest case, the magnet is diametrically magnetized, i.e., it has two oppositely magnetized regions, each of which covers an equal angular range, for example, 180° each, and is arranged symmetrically with respect to the axis of rotation. Measuring the magnetic field vector easily allows the angle of rotation to be determined.

[0007] DE 10 2018 213 402 A1 also discloses an inductive position sensor with an excitation coil and at least two receiver coils, wherein a diagnostic function is implemented.

[0008] Currently existing sensor electronics, typically implemented as ASICs, offer functional safety up to ASIL C(D) per sensor channel. To meet ASIL D requirements, the sensor electronics must be redundant, which increases costs both for the sensor (design of the sensor electronics with two complete, possibly galvanically isolated channels) and for the overall system (cable interface with an increased number of wires, more complex signal acquisition electronics and software, etc.). Disclosure of the invention

[0009] Within the scope of the present invention, a sensor system is therefore proposed for determining at least one rotational property of an element rotating about at least one rotational axis. This sensor system is designed for functional plausibility testing of an inductive angle or position sensor with the least possible additional expenditure on additional electronics and with the maximum degree of plausibility coverage. Within the scope of the present invention, a "sensor system" is generally understood to mean any device consisting of a plurality of components that is suitable for detecting, for example, measuring, at least one measured variable. In particular, the sensor system can, for example, generate at least one electrical signal corresponding to the rotational property, such as a voltage or a current, to determine the at least one rotational property of the rotating element.In particular, the sensor system can also evaluate the at least one electrical signal for determining the at least one rotation property.

[0010] In the context of the present invention, a "rotational property" is generally understood to mean a property that at least partially describes the rotation of the rotating element. This can be, for example, an angular velocity, a speed, an angular acceleration, an angular position, or another property that can at least partially characterize a continuous or discontinuous, uniform or non-uniform rotation or rotation of the rotating element. For example, the rotational property can be a position, in particular an angular position or an angular attitude, a speed, an angular acceleration, or a combination of at least two of these variables. Other properties and / or other combinations of properties can also be detected.In the context of the present invention, an "angular position" or an "angular setting" is understood to mean a rotation angle of a rotatable device, for example the rotating element or a sensor wheel of the sensor system, with respect to an axis perpendicular to the axis of rotation.

[0011] The sensor system can be configured, in particular, for use in a motor vehicle. Within the scope of the present invention, a "rotating element" is understood to mean any element that rotates about at least one axis. For example, the rotating element can be a shaft, such as a shaft in a drive engine, such as a camshaft or a crankshaft. For example, an angular position of a camshaft, a rotational speed of a camshaft, an angular acceleration of a camshaft, or a combination of at least two of these variables can be determined. Other properties and / or other combinations of properties can also be detected.

[0012] The sensor system comprises at least one circuit carrier. A "circuit carrier" can be understood as a device on which at least one electrical component can be arranged. The circuit carrier can be designed to be flexible. In particular, the circuit carrier can comprise a flexible material. The circuit carrier can in particular be selected from the group consisting of: a printed circuit board, in particular a rigid-flex circuit board, for example, a bent rigid-flex circuit board; a rigid circuit board, in particular a rigid circuit board with notches; a printed circuit board; a circuit board; and a printed circuit, in particular a printed circuit board (PCB). In particular, the circuit carrier can, for example, also have at least two surfaces arranged parallel to one another, for example, planes. For example, the circuit carrier can be constructed from a plurality of layers.In particular, have several layers.

[0013] The circuit carrier of the sensor system carries an excitation coil that encloses at least one excitation region. Furthermore, the circuit carrier carries at least two receiving coils in the excitation region. Each of the receiving coils can enclose at least two non-congruent subregions within the excitation region, which are enclosed in opposite directions by the respective receiving coil.

[0014] In the context of the present invention, a "coil" is generally understood to mean any component that has an inductance and is suitable for generating a magnetic field when current flows and / or vice versa. For example, a coil can comprise at least one completely or partially closed conductor loop or turn. In the context of the present invention, an "excitation coil" can generally be understood to mean a coil that generates a magnetic flux when an electrical voltage and / or an electrical current is applied. The excitation coil can have at least one excitation turn. In particular, the term "excitation region" can generally be understood to mean any space that is enclosed, for example, delimited, by the excitation coil. For example, the excitation region can be enclosed by the excitation turn, for example, the at least one conductor loop or turn of the excitation coil.

[0015] The at least two receiving coils can be arranged, in particular, in the excitation region on the circuit carrier. Within the scope of the present invention, a "receiving coil" is generally understood to mean a coil configured to generate a signal, which is dependent on the inductive coupling, due to an inductive coupling between the excitation coil and the receiving coil. In particular, the receiving coil can have at least one receiving winding. Furthermore, the receiving coil can, for example, enclose at least two subregions. The term "subregion" can generally be understood to mean any space enclosed by at least part of the receiving winding. For example, the receiving coil can have at least two subregions that are not congruent in opposite directions.In the context of the present invention, "opposing subregions" is generally understood to mean that the at least two subregions of the receiving coil are enclosed by at least two parts of the receiving winding that differ in their orientation. In particular, the first subregion can be enclosed by a clockwise-oriented first part of the receiving winding, whereas the second subregion can be enclosed by a counterclockwise-oriented second part of the receiving winding, or vice versa.

[0016] The sensor system further comprises at least one controller for determining the at least one rotational property from signals from the receiving coils. A "controller" can generally be understood to mean an electronic device configured to evaluate signals generated by the receiving coils, in particular voltage signals and / or current signals, and to determine the at least one rotational property of the rotating element therefrom. For example, one or more electronic connections can be provided between the controller and the other components of the sensor system to transmit the signals. The controller can, in particular, comprise a data processing device, for example, at least one computer or microcontroller. The data processing device can, for example, have one or more volatile and / or non-volatile data memories.The controller, in particular the data processing device, can, for example, be programmed to control one or more components of the sensor system. The controller can, for example, further comprise at least one interface, in particular an electronic interface and / or a human-machine interface, such as an input / output device such as a display and / or a keyboard. The controller can, for example, be centrally or decentrally constructed. Other configurations are also conceivable. In particular, the controller can, for example, be embodied in an application-specific integrated circuit (ASIC), including in the ASIC of the sensor electronics.

[0017] Furthermore, the circuit carrier carries at least one control coil. The control coil is connected to the controller. In the context of the present invention, a "control coil" is understood to mean a coil of any shape that is configured to generate at least one signal suitable for changing the signals from the receiving coils. For this purpose, the controller can control the control coil in such a way that a load resistance or load impedance of the control coil is changed. With a suitable spatial arrangement of the control coil, the change in its load resistance or load impedance will influence the signals in the sensor coils, and in particular in the receiving coils, in a defined manner, e.g., changing the amplitude of the coil signals. The change in the load resistance can be initiated at the request of the control unit of the sensor system (e.g., control bit ON / OFF), at the request of the ASIC of the sensor electronics, or automatically (e.g.,repetitively with predefined periodicity). With a particularly advantageous design, the sensor's main function (position determination) remains fully available in all operating states of the additional electronics.

[0018] For example, the control coil can generate the signal for evaluating the diagnostic information, for example the functionality of the sensor system, the integrity of components of the sensor system, in particular the functionality of the excitation coil and the receiving coils, for example correct control of the excitation coil. The control coil can thus, for example, assume a diagnostic and / or monitoring function. In particular, the control coil can, for example, have at least one turn, wherein the turn preferably only has one orientation. For example, the control coil can have at least one turn, which can, for example, be either right-curved or left-curved. In particular, the control coil can also have a plurality of turns, for example a plurality of turns arranged in several levels of the circuit carrier.

[0019] In particular, the at least one control coil can be arranged outside the excitation region. For example, the control coil can be arranged outside the area enclosed by the excitation coil.

[0020] Alternatively, the at least one control coil can also be arranged within the excitation region. For example, the control coil can be arranged together with the at least two receiving coils within the region enclosed by the excitation coil.

[0021] The controller is particularly designed to step-change the load resistance of the control coil. For example, the controller is designed to change the load resistance of the control coil between an (approximately) open circuit and an (approximately) short circuit. The change in the load resistance depends on the control signal of the controller.

[0022] Alternatively or additionally, the control unit can be designed to change the load resistance of the control coil in a modulated manner according to a predetermined pattern - also dependent on the control signal of the control unit.

[0023] The sensor system may further comprise at least one electrical or electronic switching element or control element. The controller may be configured to change the load resistance of the control coil by means of the switching element or control element.

[0024] The switching element or control element may comprise a switch, microswitch, transistor, such as a field effect transistor, operational amplifier, comparator and / or multiplexer.

[0025] The sensor system can further comprise at least one logic component, which includes the switching element. A "logic component" can generally be understood as a digital integrated circuit, which can be implemented in a range of very simple to very complex logical switching functions. The range of components extends from components with several simple logic gates, such as AND, OR, and NAND gates (see figure) as well as flip-flops, to programmable logic components such as PLDs, FPGAs, gate arrays, and custom integrated circuits (ASICs).

[0026] The diagnostic information can be generated based on signals from the receiving coils and a temporal relationship between the signals from the receiving coils and a control signal from the controller for changing the load resistance of the control coil.

[0027] The diagnostic information can be generated based on amplitudes of the signals of the receiving coils and a temporal relationship between the signals of the receiving coils and a control signal of the controller for changing the load resistance of the control coil.

[0028] The rotational properties of the rotating element can be determined based on a ratio of the signals from the receiving coils. The control unit thus retains the ability to continuously calculate the angle or position information (since it is amplitude-independent) from the sensor output signals of the receiving coils.

[0029] The control system can be a microcontroller, allowing for a compact design.

[0030] In a further aspect of the present invention, a method for diagnosing an element rotating about at least one rotation axis is proposed. The method comprises the following steps, preferably in the specified order. In addition to the aforementioned method steps, the method may also comprise further method steps. The method steps are: Providing at least one sensor system; changing a load resistance of the control coil such that signals from the receiving coils can be changed to generate at least one piece of diagnostic information; evaluating at least one signal from the receiving coils, wherein at least one piece of diagnostic information is obtained during the evaluation.

[0031] The sensor system provided is a sensor system according to the present invention, i.e., according to one of the above-mentioned embodiments or according to one of the embodiments of the sensor system described in more detail below. Accordingly, for definitions and optional configurations, reference can largely be made to the description of the sensor system. However, other configurations are also possible in principle.

[0032] Furthermore, within the scope of the present invention, a computer program is proposed which, when run on a computer or computer network, carries out the method according to the invention in one of its embodiments. Furthermore, within the scope of the present invention, a computer program with program code means is proposed in order to carry out the method according to the invention in one of its embodiments when the program is executed on a computer or computer network. In particular, the program code means can be stored on a computer-readable data carrier. Furthermore, within the scope of the present invention, a data carrier on which a data structure is stored which, after being loaded into a working and / or main memory of a computer or computer network, can carry out the method according to the invention in one of its embodiments.Also within the scope of the present invention is a computer program product with program code means stored on a machine-readable medium for carrying out the method according to the invention in one of its embodiments when the program is executed on a computer or computer network. A computer program product is understood to mean the program as a tradable product. It can in principle exist in any form, for example on paper or a computer-readable data medium, and can in particular be distributed via a data transmission network. Finally, within the scope of the present invention, a modulated data signal is proposed which contains instructions executable by a computer system or computer network for carrying out a method according to one of the described embodiments.

[0033] The sensor system according to the invention allows for functional plausibility testing of an inductive angle or position sensor with minimal additional electronics and maximum plausibility coverage. In contrast to the prior art, the sensor system according to the invention contains only one sensor channel, which is supplemented with cost-effective additional electronics for plausibility testing. Short description of the drawings

[0034] Essential and optional details and features of the invention emerge from the following description of preferred embodiments, which are shown schematically in the figures.

[0035] They show: Figure 1 shows a sensor system according to the invention in accordance with a first embodiment; Figure 2 shows an exemplary signal curve in the sensor system of the first embodiment; Figure 3 shows a sensor system according to the invention in accordance with a second embodiment; Figure 4 shows a sensor system according to the invention in accordance with a third embodiment. Embodiments of the invention

[0036] In Figure 1a sensor system 110 for determining at least one rotational property of an element rotating about at least one rotational axis 112 is shown according to a first embodiment. The sensor system 110 can be configured in particular for use in a motor vehicle, for example in a drive system. In particular, the sensor system 110 can be configured to detect at least one rotational property of a rotor. For example, the sensor system 110 can be configured to detect an angular position, a rotational speed, or a direction of rotation of the rotor. Accordingly, the rotating element can be, for example, a shaft, in particular a shaft connected to the rotor. The sensor system 110 comprises at least one circuit carrier 114. The circuit carrier 114 carries an excitation coil 116, wherein the excitation coil 116 encloses at least one excitation region 118.The circuit carrier 114 further carries at least two receiving coils 120, 122 in the excitation region 118, wherein each of the receiving coils 120, 122 can each enclose at least two non-congruent partial regions within the excitation region 118, which are enclosed in opposite directions by the respective receiving coil 120, 122. In particular, the partial regions of the receiving coils 120, 122 can each be arranged substantially mirror-symmetrically to an axis of symmetry running perpendicular to the rotation axis 112 through the rotation axis 112, wherein the axes of symmetry of the receiving coils 120, 122 can, for example, be rotated relative to one another about the rotation axis 112.

[0037] In particular, the excitation coil 116, for example a transmitting coil, can be arranged, for example integrated, on the circuit carrier 114, in particular a printed circuit board, for example a sensor circuit board. The excitation coil 116 can be configured, in particular implemented, with multiple windings in one or more planes of the circuit carrier 114, for example the sensor circuit board, for example to increase the inductance.In particular, the excitation coil 116 can, for example, be a frequency-determining element of an LC oscillator whose resonant frequency can be adjusted, in particular selected, for example by designing the excitation coil 116 and / or, for example, by means of capacitors (not shown), in particular by equipping it with capacitors, such that the resonant frequency lies, for example, in a range from 0.5 MHz to 10 MHz, in particular from 1 MHz to 7 MHz, preferably from 1.5 MHz to 5 MHz, particularly preferably from 2.5 MHz to 4.5 MHz. For example, an excitation signal, for example an exciting voltage, in particular the voltage with which the excitation coil 116 can be applied, for example, can be adjusted such that it has amplitudes in a range from 0.1 V to 20 V, for example from 0.5 V to 15 V, in particular from 0.7 V to 12 V, preferably from 1 V to 5 V.In particular, a current flow in the excitation coil 116 can create an alternating electromagnetic field, which, for example, couples inductively into the at least two receiving coils 120, 122.

[0038] The sensor system 110 further comprises at least one controller 124 for determining the at least one rotation property from signals from the receiving coils 120, 122. For this purpose, the receiving coils 120, 122 are connected to the controller 124 via at least one line or channel 126. The one or more lines or channels 126 are suitable for transmitting (output) signals SIN_OUT, COS_OUT or position signals from the receiving coils 120, 122, processed in another suitable manner, to the controller 124. The position signals can, for example, be converted into an electrical output signal from a sensor electronics unit 128 and transmitted to the controller 124. For this purpose, the sensor electronics unit 128 is arranged between the receiving coils 120, 122 and the controller 124 and is connected to the controller 124 via the at least one line or channel 126. The controller 124 is designed as a microcontroller.

[0039] Furthermore, the sensor system 110 has at least one control coil 130. The circuit carrier 114 supports the control coil 130. The control coil 130 is connected to the controller 124. Thus, the control coil 130 is connected to the controller 124 via a line or channel 132. As explained in more detail below, the controller 124 is configured to vary a load resistance of the control coil 130 such that signals from the receiving coils 120, 122 can be varied to generate at least one piece of diagnostic information. The line 132 is suitable for transmitting a control signal TEST_IN from the controller 124 to the control coil 130.

[0040] The sensor system 110 further comprises at least one electrical or electronic switching element or control element 134. In principle, the switching element 134 can comprise a switch, microswitch, transistor, operational amplifier, comparator, and / or multiplexer. In the embodiment shown, the switching element 134 is a transistor 136. In the embodiment shown, the sensor system 110 further comprises at least one logic component 138 having the switching element 134. The switching element 134 or the logic component 138 is designed or connected in particular as a so-called open drain buffer. The controller 124 is designed to change the load resistance of the control coil 130 by means of the switching element 134. More precisely, the controller 124 is designed to change the load resistance of the control coil 130 in steps.Thus, in the embodiment shown, the controller 124 is designed to change the load resistance of the control coil 130 between an (approximately) open circuit and an (approximately) short circuit.

[0041] In the sensor system 110, the diagnostic information can be generated based on signals SIN_OUT, COS_OUT of the receiving coils 120, 122 and a temporal relationship between the signals of the receiving coils 120, 122 and a control signal TEST_IN of the controller 124 for changing the load resistance of the control coil 130. In particular, the diagnostic information can be generated based on the amplitudes of the signals SIN_OUT, COS_OUT of the receiving coils 120, 122 and a temporal relationship between the signals of the receiving coils 120, 122 and the control signal TEST_IN of the controller 124 for changing the load resistance of the control coil 130. The rotational property of the rotating element 112 can be determined based on a ratio of the signals SIN_OUT, COS_OUT of the receiving coils 120, 122.

[0042] At the request of the controller 124, such as by a pulsed change in the control signal TEST_IN, the load resistance of the control coil 130 in the coil system of the sensor system 110 is changed. In the simplest embodiment, the effective load resistance of the control coil 130 changes abruptly between (approximately) open circuit and (approximately) short circuit depending on the control signal TEST_IN.

[0043] Figure 2 shows an exemplary signal curve in the sensor system 110 of the first embodiment. Time is plotted on the X-axis 140. The control signal TEST_IN and the signals SIN_OUT, COS_OUT of the receiving coils 120, 122 are plotted on the Y-axis 142. The signals SIN_OUT, COS_OUT of the receiving coils 120, 122 have a substantially sinusoidal or cosinusoidal curve. A sudden change in the control signal TEST_IN results in a change in the amplitude, for example, in the COS_OUT signal.

[0044] When the control signal TEST_IN switches from LOW to HIGH, the control coil 130 is virtually short-circuited by the low-impedance state of the switching element 134 in the form of an output transistor of the logic module 136. Caused by the low-impedance load of the control coil 130, smaller amplitudes can be detected in the output signals SIN_OUT and COS_OUT as long as the control signal TEST_IN remains at HIGH.

[0045] The angle or position information in the signals SIN_OUT, COS_OUT does not depend on their amplitudes, but on the ratio SIN_OUT / COS_OUT and can be calculated in the controller 124 using an arctangent function, for example in the form: Position = arctan(sin / cos).In summary, the functionality of the sensor system 110 can now be monitored by the controller 124 by monitoring the amplitudes of the sensor output signals SIN_OUT, COS_OUT, as well as their temporal relationship with the control signal TEST_IN. The controller 124 retains the ability to continuously calculate the angle or position information from the sensor output signals SIN_OUT, COS_OUT, since this is amplitude-independent.

[0046] Figure 3 shows a sensor system 110 according to the invention according to a second embodiment. Only the differences from the first embodiment are described below, and identical or comparable components are provided with the same reference numerals. In the second embodiment, the switching element 134 is a field-effect transistor 144 in the form of a MOSFET. The functionality of the second embodiment is fundamentally identical to the first embodiment.

[0047] Figure 4shows a sensor system 110 according to the invention according to a third embodiment. Only the differences from the first embodiment are described below, and identical or comparable components are provided with the same reference numerals. In the second embodiment, the switching element 134 is a multiplexer 146 in the form of an analog two-channel switching element. A receiving coil 120 of the receiving coils 120, 122 is integrated into the multiplexer.

[0048] At the request of the controller 124, such as by a pulse-like change in the control signal TEST_IN, the received signals are evaluated in the control coil 130 instead of the receiving coil 120. Otherwise, the functionality of the third embodiment is essentially identical to the first embodiment.

[0049] In the first, second, and third embodiments, the functionality of the sensor system according to the invention was illustrated by influencing analog signals SIN_OUT, COS_OUT (collectively, analog signal interface). As an alternative to analog signals SIN_OUT, COS_OUT, the position information can be converted into an electrical output signal from the sensor electronics 128 in another suitable manner and transmitted to the controller 124. In particular, a suitable digital signal interface can be used for communication or for the connection between the sensor electronics 128 and the controller 124. In particular, a suitable bidirectional digital signal interface can be used here, which, among other things, maps the functionality of the position signal channel 126 and the control signal channel 132.

[0050] The use of the described sensor system 110 can be verified by measuring the signals at the sensor electronics and analyzing the circuit and, if applicable, coil systems.

Claims

1. Sensor system (110) for determining at least one rotation property of an element rotating about at least one axis of rotation (112), comprising at least one circuit carrier (114), wherein the circuit carrier (114) has an excitation coil (116), wherein the excitation coil (116) encloses at least one excitation region (118), wherein the circuit carrier (114) furthermore has at least two receiving coils (120, 122) in the excitation region (118), wherein the sensor system (110) furthermore has at least one controller (124) for determining the at least one rotation property from signals from the receiving coils (120, 122), wherein the rotation property of the rotating element is an angular position of the rotating element and the angular position of the rotating element is able to be continuously determined on the basis of a ratio of the signals from the receiving coils (120, 122), characterized in that the circuit carrier (114) furthermore has at least one control coil (130), wherein the control coil (130) is connected to the controller (124), wherein the controller (124) is designed to change a load resistance of the control coil (130) in such a way that it is possible to change signals from the receiving coils (120, 122) for generating at least one item of diagnostic information.

2. Sensor system (110) according to the preceding claim, wherein the controller (124) is designed to change the load resistance of the control coil (130) in a stepwise manner.

3. Sensor system (110) according to either of the preceding claims, wherein the controller (124) is designed to change the load resistance of the control coil (130) between an open circuit and a short circuit.

4. Sensor system (110) according to one of the preceding claims, furthermore comprising at least one electrical or electronic switching element (134), wherein the controller (124) is designed to change the load resistance of the control coil (130) by means of the switching element (134).

5. Sensor system (110) according to the preceding claim, wherein the switching element (134) comprises a switch, microswitch, transistor (136), operational amplifier, comparator and / or multiplexer (146).

6. Sensor system (110) according to one of the two preceding claims, furthermore comprising at least one logic chip (138), wherein the logic chip (138) comprises the switching element (134).

7. Sensor system (110) according to one of the preceding claims, wherein the diagnostic information is able to be generated on the basis of signals from the receiving coils (120, 122) and a temporal relationship of the signals from the receiving coils (120, 122) with a control signal from the controller (124) to change the load resistance of the control coil (130).

8. Sensor system (110) according to one of the preceding claims, wherein the diagnostic information is able to be generated on the basis of amplitudes of the signals from the receiving coils (120, 122) and a temporal relationship of the signals from the receiving coils (120, 122) with a control signal from the controller (124) to change the load resistance of the control coil (130).

9. Sensor system (110) according to one of the preceding claims, wherein the controller (124) is a microcontroller.