CN114427924A

CN114427924A - Sensor system for determining the temperature and at least one rotational characteristic of a rotating element rotating about at least one axis of rotation

Info

Publication number: CN114427924A
Application number: CN202111269598.0A
Authority: CN
Inventors: A·雅山; A·赫茨贝格尔; J·舍费尔; S·盖尔; T·普赖斯; P·梅林格
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2020-10-29
Filing date: 2021-10-29
Publication date: 2022-05-03
Also published as: DE102020213593A1

Abstract

A sensor system for determining a temperature and at least one rotation characteristic of a rotating element rotating about at least one axis of rotation is proposed. The sensor system comprises at least one temperature sensor provided for detecting at least one temperature of the rotating element, the temperature sensor having a temperature sensor element, a transmitter unit with at least one transmitter coil and a receiver unit with at least one receiver coil, the temperature sensor element and the receiver unit being mountable on the rotating element, the receiver unit being configured for inductively transmitting a signal of the temperature sensor element to the transmitter unit. The sensor system further comprises at least one inductive position sensor arranged to detect at least one information about a rotational characteristic of the rotating element and at least one analysis processing unit arranged to generate at least one first signal having at least one information about the detected temperature and at least one second signal having at least one information about the rotational characteristic.

Description

Sensor system for determining the temperature and at least one rotational characteristic of a rotating element rotating about at least one axis of rotation

Technical Field

The invention relates to a sensor system for determining a temperature and at least one rotational characteristic of a rotating element rotating about at least one axis of rotation.

Background

From the prior art, numerous sensors are known which detect at least one rotational characteristic of a rotating element. Examples of such sensors are described in Konrad Reif (publisher) "sensorim Krafffahrzeug (second edition, 2012), pages 63-74 and pages 120-129. For example, the position of the camshaft of the internal combustion engine relative to the crankshaft can be determined with the aid of a hall sensor with a so-called phase sensor.

For example, in order to achieve traction in electric vehicles, either asynchronous motors or synchronous motors are generally used, which each consist of a stationary stator and a rotating rotor. The stator usually carries three winding phases, for example, offset from one another by 120 °/p, where p denotes the number of pole pairs. In asynchronous machines, the rotor is usually composed of electrically conductive bars which are short-circuited annularly at the ends. Thus, when the rotor field rotates, the rotor canTo induce a voltage in the rods that causes a current flow that in turn builds up an opposing magnetic field and a rotational motion occurs. If the rotor field and the stator rotate equally fast, the induced voltage is zero. A difference in rotational speed occurs, which is referred to as slip (Schlupf) and defines the torque of the motor. In a synchronous machine, the rotor comprises a rotating part

The rotating portion carries an excitation coil in which a direct current flows and a static magnetic field is generated. Alternatively, a permanent magnet may be used as the rotor. This then relates to permanently excited synchronous machines which have a higher efficiency due to the unpowered excitation and can therefore be more suitable for traction applications. The rotational speed of the rotor can be the same as the rotational speed of the excitation field, which is determined in principle. The torque may depend on the phase offset, i.e. the angular difference between the stator field and the rotor. For torque regulation, inverter control and corresponding supply of stator coil signals, the rotational speed of the rotor must be known for asynchronous machines and the absolute angular position of the rotor must be known for synchronous machines. In both cases (synchronous motor and asynchronous motor), the direction of rotation should additionally be determined, in particular for reasons of functional safety. The maximum power of the motor may also be limited by the stator temperature and the rotor temperature.

For determining the rotor position, it is known to use a so-called converter (Resolver). This involves a measurement value converter (Messumformer) in which the rotor set rotational speed is fixedly mounted on the shaft of the motor. The excitation coil and the plurality of receiver coils are mounted on the stator in a circularly encircling manner. The excitation coil is loaded with an alternating voltage signal and the electromagnetic alternating field is distributed over the entire arrangement. Depending on the angle of rotation, a sine-shaped amplitude-modulated voltage can be induced in the first receiver coil, while a cosine-shaped amplitude-modulated voltage is induced in the second receiver coil. The supply of the excitation signal as well as the readout signal can be implemented in the power electronics or in a dedicated module in the controller for the motor regulation. However, the converter requires a relatively large installation space, requires complex signal provision and processing, and has to be assembled with very low mechanical tolerances in order to achieve a sufficiently high accuracy. For these mentioned reasons, the system cost may be correspondingly high. Furthermore, for space reasons, it may not be possible to fit a redundant receiver coil system on the stator of the converter to improve the usability of the sensor. Thus, sensor failure may result in a vehicle "tie-up" (liegenbleinben).

Since the temperature resistance of the insulating varnish of the stator winding is limited, the stator temperature is decisive for the maximum current intensity in the stator coil and thus for the torque to be output. It is known to use temperature sensors wound into the stator coils for determining the temperature. The temperature distribution can be deduced by means of a model. The rotor temperature may be critical mainly in asynchronous machines, since in squirrel cage rotors

The high current flows permanently, which has not been taken out until now and the rotor temperature is calculated only by means of a model. The lack of measurement information about the rotor temperature limits the performance of the electric machine and makes modeling with corresponding expenditure and inaccuracies absolutely necessary, see DE 102014213103. In the case of permanently excited synchronous machines, an excessively high rotor temperature can lead to demagnetization of the permanent magnets. In the case of asynchronous machines, the rotor temperature determines the quality of the torque accuracy.

Although several advantages arise from these sensors, these advantages still include potential for improvement. Therefore, the integration of these types of sensors into a range of vehicles has hitherto not been economical due to the complex technology, the required installation space and the relatively high costs.

Disclosure of Invention

It is therefore proposed within the scope of the present invention to provide a sensor system for determining the temperature and at least one rotation characteristic of a rotating element rotating about at least one axis of rotation, which sensor system at least reduces the above-mentioned disadvantages. In particular, a sensor system is proposed which represents an economically and structurally acceptable combination of a position sensor and a temperature sensor. Within the scope of the present invention, a "sensor" is understood to mean in principle any device which is suitable for detecting at least one measured variable. A "system" may be understood as any device having at least two components. Correspondingly, a "sensor system for determining temperature and rotational behavior" is understood to mean a sensor system in which: the sensor system is provided for detecting, for example measuring, at least one temperature and at least one rotation characteristic, and can generate at least one electrical signal, for example a voltage or a current, for example, in accordance with the detected characteristic. Combinations of characteristics may also be detectable. Within the scope of the present invention, "rotational characteristic" is understood in principle to mean a characteristic in which: the characteristic describes, at least in part, the rotation of the rotating element. This may relate, for example, to an angular velocity, a rotational speed, an angular acceleration, an angular position or other characteristic, which may at least partially characterize a continuous or discontinuous, uniform or non-uniform rotation or turning of the rotating element. For example, the rotation behavior may relate to a position (in particular an angular position), a rotational speed, an angular acceleration or to a combination of at least two of these variables. Other characteristics and/or other combinations of characteristics may also be detectable. Within the scope of the present invention, "angular position" is understood in principle as the angle of rotation of a rotatable device, for example a rotating element or a sensor wheel (geberad), about an axis perpendicular to the axis of rotation.

The sensor system can be provided in particular for use in motor vehicles, in particular for traction applications of an electric machine. Within the scope of the present invention, a "rotating element" is understood in principle as any element that rotates about at least one axis. For example, the rotating element may be a shaft, for example in a drive machine, for example a camshaft or a crankshaft of an internal combustion engine or a rotor shaft of an electric motor. For example, the angular position of the camshaft or the rotational speed of the camshaft or the angular acceleration of the camshaft or a combination of at least two of these variables may be determined. Other characteristics and/or other combinations of characteristics may also be detectable.

The sensor system comprises at least one temperature sensor arranged to detect at least one temperature of the rotating element. The temperature sensor has a temperature sensor element, a transmitter unit with at least one transmitter coil and a receiver unit with at least one receiver coil. The temperature sensor element and the receiver unit can be mounted on the rotating element. The receiver unit is designed to inductively transmit the signal of the temperature sensor element to the transmitter unit. Accordingly, the transmitter unit and the receiver unit are spatially and structurally separated from each other.

The sensor system further comprises at least one inductive position sensor arranged to detect at least one information about a rotational characteristic of the rotating element. In the context of the present invention, an "inductive position sensor" is understood to mean, in principle, any sensor which is able to generate information, in particular a signal (in particular a measurement signal, in particular an electrical measurement signal, for example a voltage or a current), in accordance with a detected property, the generation of the measurement signal being based on a change in an electromagnetic alternating field or a magnetic flux. In particular, the detected characteristic may comprise a position, such as an angular position. In particular, the inductive position sensor may relate to an inductive angle sensor or a displacement sensor (Wegsensor). In particular, the inductive position sensor may be an inductive rotor position sensor (Rotorlagesensor or rotodisplacement sensor). However, other configurations are also possible in principle.

The sensor system further comprises at least one evaluation unit, which is provided to generate at least one first signal having at least one piece of information about the detected temperature and at least one second signal having at least one piece of information about the rotation behavior. Here, an "evaluation unit" is generally understood to mean an electronic device that: the electronic device is provided for evaluating signals generated by the inductive position sensor and/or the temperature sensor. For example, one or more electronic connections may be provided for this purpose between the inductive position sensor and/or the temperature sensor and the evaluation unit. For example, the analysis processing unit may comprise at least one data processing device, such as at least one computer or microcontroller. The data processing device can have one or more volatile and/or nonvolatile data memories, wherein the data processing device can be set, for example, by programming techniques in order to actuate the inductive position sensor. For example, the evaluation unit can be constructed centrally or else decentrally. Other configurations are also contemplated. The signal evaluation in the evaluation unit can be carried out in such a way that the evaluation unit evaluates all signals received from the temperature sensor and the inductive position sensor and converts these signals into two output signals, namely a first signal and a second signal. The first signal may be indicative of temperature and the second signal indicative of a rotation characteristic, such as a rate of rotation. The first signal and the second signal may be both analog, both digital or one analog and one digital.

In accordance with the sensor system according to the invention, it is proposed to advantageously combine an (inductive) rotor position sensor with an inductive wireless signal and/or energy transmission device of the temperature sensor to the motor rotor. The inductive transmission device serves to transmit signals from the temperature sensor and, if necessary, energy for supplying the temperature sensor. This combination of at least two sensor technologies offers the potential not only for installation space savings but also for cost savings of the electric drive, in particular in an electric drive assembly.

The transmitter unit is designed to supply the receiver unit with energy, for example with current, inductively. The temperature sensor element is connected to the receiver unit. The temperature sensor element is therefore also supplied with energy by means of the receiver unit. The temperature sensor element may be a resistor, for example an NTC (negative temperature coefficient) sensor element or a PTC (positive temperature coefficient) sensor element.

The transmitter unit may be an inductive transmitter unit. The receiver unit may be an inductive receiver unit. For example, the transmitter unit is an RFID reader and the receiver unit is an RFID transponder. Therefore, known solutions for wireless transmission of signals and energy to the rotor temperature sensor by means of inductive technology or RFID technology can be used. In this case, the transmitter unit supplies energy to the receiver unit and the temperature sensor element. In the opposite direction, the receiver unit inductively transmits the signal of the temperature sensor element to the transmitter unit. The temperature sensor element may be integrated into the rotating element.

The inductive position sensor and the transmitter unit can be arranged together on a carrier, for example a circuit carrier. A "circuit carrier" is understood to mean a device in which: at least one electrical component may be arranged on the device. The circuit carrier can be flexibly configured. In particular, the circuit carrier may comprise a flexible material. The circuit carrier may be selected in particular from the group consisting of: printed circuit boards, in particular rigid flexible printed circuit boards, for example curved rigid flexible printed circuit boards; rigid printed circuit boards, in particular with recesses; a circuit card; circuit boards and printed circuits, in particular "printed circuit boards" (PCBs).

The circuit carrier may be arranged substantially coaxially with the axis of rotation. For example, the circuit carrier can be essentially circular or segment-shaped

A sensor wheel surrounding the sensor system described further below or a circular segment of the sensor wheel. In the context of the present invention, the term "substantially circular" is understood in principle to mean that the component described has a radius of curvature. The radius of curvature can vary within the component by a value of 0% to 80%, preferably by a value of 0% to 50%, more preferably by a value of 0% to 20%, particularly preferably by a value of 0% to 5%. In particular, the radius of curvature may also be constant. Alternatively or additionally, the circuit carrier may also consist of two or more sections, which may each be of a flat or curved configuration, for example, and which may be connected to one another, for example. These segments can then also be generally identical to the axis of rotationThe shafts are arranged even if the individual segments are subsequently arranged, for example tangentially. Furthermore, the circuit carrier can be arranged in a housing, in particular in an injection-molded housing.

The transmitter coil may face the receiver coil and preferably be opposite the receiver coil. With this structure, the air transformer is constructed to some extent. Electronic evaluation modules are required both on the stator side and on the rotor side, which can be placed either on the same carrier (for example a printed circuit board) or on another carrier. The opposing arrangement of the coils has the following advantages: communication is maintained permanently even at high rotational speeds.

The inductive position sensor may have at least one coil arrangement, which is arranged on the circuit carrier. The coil arrangement may comprise at least one excitation coil and at least two receiver coils. Within the scope of the present invention, a "coil arrangement" can in principle be understood as any device comprising at least one coil. Within the scope of the present invention, a "coil" is understood in principle as any component: the member has an inductance and is adapted to generate a magnetic field when a current flows and/or vice versa. For example, the coil may comprise at least one fully or partially closed conductor loop or winding. In the context of the present invention, an "excitation coil" is understood in principle to be a coil which generates a magnetic flux when a voltage and/or a current is applied. The excitation coil may have at least one excitation winding. In the context of the present invention, a "receiver coil" is understood in principle to mean a coil in which: the coil is arranged to generate a signal based on an inductive coupling between the excitation coil and the receiver coil, the signal being dependent on the inductive coupling. For example, the coil arrangement may have a receiver coil system. Within the scope of the present invention, a "receiver coil system" is understood in principle as any device comprising at least two receiver coils.

The excitation coil can be substantially circularly shaped. With respect to the term "substantially circular", reference is made to the above definition. The excitation coil and the receiver coil may be configured as described in DE 102017210655. The receiver coils may substantially completely surround the axis of rotation in the circumferential direction, wherein each receiver coil is formed by a plurality of adjacent sub-windings, wherein the adjacent sub-windings are oppositely oriented in the direction of current flow. In this case, each partial winding is formed, in terms of the radial direction extending outward from the rotational axis, by at least two segments of a conductor path (Leiterbahnen) bent to the left in the shape of a circular arc and by at least two segments of a conductor path bent to the right in the shape of a circular arc. All left-curved and all right-curved conductor paths have the same radius of curvature. All left-curved conductor paths and all right-curved conductor paths extend between two concentric circles around the axis of rotation, the first circle having a first radius and the second circle having a second radius, wherein a third circle is given which is concentric with the first circle and has a third radius which is derived from the average of the first radius and the second radius, wherein the first right-curved conductor path extends through three points: through a first point located on a first circle; passing a second point located on a third circle and twisted in the circumferential direction relative to the first point by a quarter of the measurement range; and passes through a third point which lies on the second circle and which is twisted in the circumferential direction relative to the first point by half of the measuring range. The additional rightward curved conductor path results from the preceding rightward curved conductor path by rotating half of the measuring range in the circumferential direction about the axis of rotation. The leftward bent conductor path is obtained by mirroring the rightward bent conductor path on the following radial lines: the radial lines extend from the axis of rotation through the intersection of the respective rightward curved conductor paths and the third circle. A partial winding of a receiver coil may be defined here as the part of the receiver coil which is surrounded by conductor paths of the receiver coil which do not intersect one another. The orientation of the sub-windings is determined via the current flow through the receiver coil. When a current flows through the receiver coil, the oppositely oriented partial windings each have an opposite current flow, i.e. in the partial winding having the first orientation, the current runs clockwise or to the right through the partial winding, and in the partial winding having the second orientation, the oppositely oriented partial winding, the current runs counterclockwise or to the left through the partial winding. That is, as an example, the sub-windings may be constructed as diamonds with curved sides. For example, the four sides of such a rhombus can be constructed from two parts each of two left-hand and two right-hand conductor paths. For example, in this case, the current flow directions can be opposite to one another in at least two sections of the conductor path bent to the left, which sections form the partial windings. Likewise, in at least two sections of the conductor path bent to the right, which sections form the partial windings, the current running directions can be opposite to one another. In this case, the structure of the partial windings is to be understood such that an imaginary straight line, which starts from the axis of rotation and extends in the radial direction, intersects the left-hand and right-hand curved circular-arc-shaped conductor paths of the receiver coil when the straight line extends through the interior of the receiver coil. In this way it is also possible, for example, for the amplitude of the alternating voltage induced in the receiver coil or the measurement signal to be substantially sinusoidal dependent on the angle of rotation.

The inductive position sensor may comprise a plurality (n) of receiver coils, where n is a positive integer. The sinusoidal signals generated by the n receiver coils may be out of phase with each other. For example, for n-2, adjacent sinusoidal signals may have a phase spacing of 2 pi/(2 n) and/or 360 °/(2 n). Furthermore, for n ≧ 3, for example, adjacent sinusoidal signals may have a phase spacing of 2 π/(2n) and/or 360 °/(2 n). In particular, adjacent sinusoidal signals from exactly two receiver coils may have a phase separation of 90 °. In particular, adjacent sinusoidal signals from exactly three receiver coils may have a phase spacing of 120 °.

The inductive position sensor may have at least one Application Specific Integrated Circuit (ASIC), which is arranged on a circuit carrier. An "application specific integrated circuit" (ASIC) is to be understood as in principle any electronic circuit implemented as an integrated circuit.

An application specific integrated circuit may be provided for providing the excitation signal to the excitation coil. The application-specific integrated circuit can be arranged on the circuit carrier and connected to exactly one excitation coil and at least two receiver coils. By "providing an excitation signal" it is understood that the application specific integrated circuit is provided for generating the excitation signal and/or the application specific integrated circuit is provided for loading the excitation coil with the excitation signal. Within the scope of the present invention, an "excitation signal" is understood to mean an electrical signal, in particular at least one alternating voltage and/or at least one alternating current. The excitation signal may be a substantially sinusoidal excitation signal. In the context of the present invention, "sinusoidal" is understood to mean, in principle, any shape having a sinusoidal course. For example, a full sinusoidal course may be included or only a portion of a sinusoidal course may be included. "substantially sinusoidal" is understood to mean an embodiment with a completely sinusoidal course, wherein the following deviations are conceivable: the deviation is not more than 20%, in particular not more than 10%, or even not more than 5% of the absolute value of the sinusoidal shape. A "complete sinusoid" is to be understood here to mean, in particular, a course of the sinusoid comprising at least one period. Here, the sinusoid may start from the zero point or any other point of the sinusoid. For example, the sinusoidal shape can also be composed of other functions in sections, so that overall the sinusoidal shape is approximated. The excitation signal may have an amplitude in the range of 0.1V to 10V, preferably 2.5V to 5V. The excitation signal may have a frequency in the range of 1MHz to 20MHz, preferably 2.5 to 7.5 MHz. The application specific integrated circuit may have at least one oscillator circuit. For example, the oscillator circuit may drive an LC oscillator in which an excitation coil and a capacitor function as elements that determine the frequency. By applying the excitation coil with an excitation signal, an electromagnetic alternating field can be generated, which couples into the receiver coil and induces a corresponding alternating voltage and/or alternating current therein, for example. An inductive position sensor may be provided for detecting an inductive coupling and/or a change in an inductive coupling between the excitation coil and the at least one receiver coil. The excitation coil may be arranged to generate an electromagnetic alternating field in response to being loaded with an excitation signal. The excitation coil and the receiver coil may be coupled such that the electromagnetic alternating field induces an alternating voltage in the receiver coil. The receiver coil may be arranged such that, when the rotary element rotates about the axis of rotation, the receiver coil generates a signal related to the angle of rotation.

The application-specific integrated circuit may be provided for processing the signal generated by the receiver coil and providing it as at least one first output signal to at least one first output and as at least one second output signal to at least one second output. The designations "first" and "second" output signals are to be understood as pure designations and in particular no description is given with respect to the order or the presence of further output signals. "processing" is in principle to be understood as any signal processing operation for generating an output signal, such as for example analysis processing, filtering, demodulation. The signal processing can be done digitally and/or analog. The application-specific integrated circuit can be provided in particular to deduce the magnitude and phase of the coupling by demodulating the signal induced in the receiver coil by means of a carrier signal, i.e. the signal of the excitation coil (also referred to as transmitter coil). The magnitude can in particular vary continuously with the angle of rotation. For example, the phase (Phasenlage) may be 0 ° or 180 °. The application-specific integrated circuit may have at least one demodulation device which is provided for demodulating, in particular synchronously demodulating, the signal of the receiver coil. Demodulation may include multiplication with the excitation signal. For example, a preferably offset-free sine/cosine system can be generated by multiplying the magnitude by a cosine function, in particular when two receiver coils having a phase offset of 90 ° with respect to the measuring range are used. In particular, three-phase sinusoidal signals can be generated when three receiver coils with a phase offset of typically 120 ° with respect to the measurement range are used, which can be converted into a sine/cosine system, for example, by applying a clarke transformation. The angle of rotation can then be deduced by means of an arctan function. The application specific integrated circuit may have at least one low pass filter. The low-pass filter may have a cut-off frequency in the range of 50kHz up to 500kHz, preferably 100 kHz. The lower cut-off frequency may be significantly lower, since only the offset should be compensated, so that for example 0.1Hz is sufficient. For example, the application specific integrated circuit may first demodulate the signal of the receiver coil and then filter it with a low pass filter. The application specific integrated circuit may have at least one amplifier. The amplifier may be arranged to amplify the signal of the receiver coil, in particular the filtered signal. "amplification" is to be understood as an increase in the amplitude of the signal. The application specific integrated circuit may also be arranged to load the signal of the receiver coil with a DC (direct current) offset. The first output signal and the second output signal can be transmitted from the first and second outputs, for example, via at least one electrical signal line, in particular a cable, to a second evaluation unit, in particular an evaluation unit which is embodied separately from the circuit carrier.

The sensor system may have at least one sensor wheel connectable to the rotating element. The receiver unit may be connected to the sensor wheel or can be combined with the sensor wheel. The receiver coil of the receiver unit may be arranged coaxially with the sensor wheel. In the context of the present invention, a "sensor wheel" is understood to mean, in principle, any component that can be connected to a rotating element and is provided to generate, when connected to the rotating element, at least one measurable signal, in particular a change in the magnetic field, with each revolution of the rotating element. For example, the sensor wheel can be permanently or reversibly connected or connectable to the rotary element, or can also be formed integrally with the rotary element or integrated into the rotary element. The sensing wheel may have a sensing wheel profile. In the context of the present invention, a "sensor contour" is understood in principle to mean the entirety of the contour elements and the intermediate spaces arranged between the contour elements. In the context of the present invention, a "profile element" of a sensor wheel can in principle be understood to mean any profile of the sensor wheel, in particular a projection, for example a pin-shaped, toothed or sawtooth-shaped projection, or a cutout or recess, for example a hole.

For example, the sensor wheel may be configured to "mask" the area of the receiver coil structure based on its position. The coupling between the transmitter coil arrangement and the receiver coil can thereby be influenced in dependence on the angle of rotation. Typical values for the coupling coefficient may range, for example, from-0.3 to + 0.3. The coupling coefficient is understood here to mean, in particular, the amplitude ratio between the received signal and the transmitted signal or the excitation signal. The coupling coefficient can in particular vary sinusoidally with the angle of rotation.

The inductive position sensor may have at least one coil arrangement. As mentioned, the coil arrangement may in particular comprise at least one position sensor excitation coil and at least two position sensor receiver coils. The transmitter coil may be arranged coaxially with the coil arrangement.

The coil arrangement may substantially enclose the sensor wheel or at least one circular segment of the sensor wheel in a circle segment shape or a circle. In particular, the coil arrangement, in particular the coil arrangement arranged on the circuit carrier, can cover at least one profile element of the sensor wheel and at least one intermediate space between two profile elements in at least one angular position of the sensor wheel.

The sensor wheel can be configured rotationally symmetrically. The sensor wheel may have the same number of conductive blades and non-conductive or less conductive blades and/or grooves. The conductive blade may have a first opening angle α and the non-conductive or less conductive blade and/or the recess may have a second opening angle β. The sum of the first and second opening angles may correspond to the entire angular measurement range of the inductive position sensor. The first and second opening angles may be the same or may be different. The sensor wheel can be fastened to the rotary element by means of a screw connection and/or an adhesive connection.

The evaluation unit can be provided to deduce the angular position Φ of the sensor wheel from the signals of the receiver coils. The sensor system, in particular the inductive position sensor, can be provided for detecting an inductive coupling and/or a change in the inductive coupling between the excitation coil and the at least one receiver coil. In particular, the sensor system may be provided for detecting an inductive coupling between the excitation coil and the receiver coil caused by a movement and/or position of the sensor wheel and/or a change in the inductive coupling caused by a movement and/or position of the sensor wheel. The sensor system can be provided in particular for determining the absolute or relative angular position of the rotary element from a change in the inductive coupling between the excitation coil and the receiver coil, which is caused by the movement and/or position of the sensor wheel. Here, "relative angular position" is understood in principle to mean a position relative to the period defined by the receiver coil. In particularThe second evaluation unit can be configured to generate at least one quotient signal (Quotientensignal) of the at least two signals of the at least two receiver coils. For example, equation

tan Φ -sin Φ/cos Φ can be used to calculate the angular position Φ from the two signals generated by the two receiver coils. For example, a clarke transform may be used to calculate the angular position Φ from the three signals generated by the three receiver coils. In particular, the evaluation unit can have at least one evaluation circuit. In particular, the evaluation circuit can be provided for evaluating the signals of the position sensor. The analysis processing circuitry may for example relate to a processor. The evaluation unit can be configured, in particular, separately from the circuit carrier and can be connected to the circuit carrier via at least one connection (e.g., a cable). The inductive position sensor may be arranged to transmit the first and second output signals to the second analysis processing unit.

A suitably shaped metallized surface (sensor wheel structure) of a dielectric carrier (possibly a printed circuit board) may also be used as the sensor wheel.

The coils of the stator part and the RFID coils on the sensor wheel and rotor part are exemplary and advantageous to implement as conductor paths or metallization surfaces of a printed circuit board. Furthermore, other embodiments of the stator part and the rotor part are possible, which enable the required electromagnetic interaction. Generally to conductor paths and metallization planes on or at a dielectric carrier.

The sensor system may be mounted on an axial end of the rotating element. For example, the sensor system can be mounted on the front end of the rotating element.

The transmitter unit can be arranged within the position sensor, outside the position sensor or axially offset from the position sensor.

The temperature sensor and the inductive position sensor may have the same or different operating frequencies. The transmitter unit and the receiver unit of the temperature sensor may use an operating frequency higher than 0.1MHz, which is suitable for the respective specific application. Reserve 3 bands for RFID: low frequency: 125kHz, high frequency: 13.56MHz, ultra high frequency: 900 MHz.

In principle, the mentioned frequency band RFID bands are conceivable. Preferably, the 13.56MHz (high frequency) band is used in preference, since here a good compromise in terms of cost, range and installation space of the antenna is achieved. The position sensor preferably operates with an operating frequency in the range of approximately 2 to 20MHz, in particular 2.5 to 7.5 MHz. The RFID portions of the position sensor and the temperature sensor preferably operate at different operating frequencies. The same operating frequency may also be used for the location sensor and the RFID portion of the sensor.

The transmitter unit and the receiver unit may be configured to detect at least one further physical characteristic of the rotating element. In addition to the temperature sensor(s) on the rotor, the RFID part can also be used for detecting other physical parameters in/on the rotor, such as acceleration sensors, strain gauges (dehnnungsmessstreifen) etc.

In addition to the angular position of the rotating element (e.g. a rotor position sensor for the rotor shaft), the position sensor may also be implemented for detecting a translational movement (e.g. a linear displacement sensor).

The analysis processing unit may comprise a first analysis processing circuit for generating the first signal and a second analysis processing circuit for generating the second signal.

The first analytical processing circuit may be separate from or integrated with the second analytical processing circuit. For example, the first analysis processing circuit and the second analysis processing circuit are provided as Integrated Circuits (ICs).

For rotor temperature detection 3 elements can be used: receiver coils, analysis processing electronics and sensors or sensor elements. These 3 elements may be arranged at different positions. Preferably, only the sensor should be positioned at the hottest part of the rotor, while the evaluation electronics and the receiver coil are placed in the region of the cooler end side of the rotor.

In another aspect of the invention, a method for determining at least one temperature and at least one rotation characteristic of a rotating element rotating about at least one axis of rotation is proposed. The method includes using at least one sensor system. The method comprises the following steps, preferably in the order indicated. In addition to the mentioned method steps, the method may also comprise further method steps. The method comprises the following steps:

detecting at least one temperature of the rotating element by means of at least one temperature sensor;

detecting at least one piece of information about a rotational characteristic of the rotating element by means of at least one inductive position sensor;

at least one first signal with at least one piece of information about the detected temperature and at least one second signal with at least one piece of information about the rotational behavior of the rotating element are generated by means of at least one evaluation unit.

The method is carried out using the sensor system according to the invention, i.e. according to one of the embodiments mentioned above or according to one of the embodiments described in more detail below. Accordingly, reference is largely made to the description of the sensor system for definitions and alternative configurations. However, in principle other configurations are also possible.

In addition, within the scope of the present invention, a computer program is proposed, which, when running on a computer or a computer network, executes the method according to the present invention in one of its configurations. Furthermore, in the scope of the present invention, a computer program with program code means is proposed for executing the method according to the invention in one of its configurations when the program is implemented on a computer or a computer network. In particular, the program code means may be stored on a computer readable data carrier. In addition, within the scope of the present invention, a data carrier is proposed on which a data structure is stored, which data structure, after being loaded into a working memory and/or a main memory of a computer or a computer network, can carry out the method according to the present invention in one of its configurations. In the context of the present invention, a computer program product is also proposed, which has program code means stored on a machine-readable carrier, in order to carry out the method according to the invention in one of its configurations when the program is implemented on a computer or a computer network. A computer program product is understood here to be a program as a tradable product. The program may in principle be present in any form and may thus be embodied, for example, on a paper or computer-readable data carrier and may be distributed, in particular, via a data transmission network. Finally, in the scope of the present invention, a modulated data signal is proposed, which data signal contains instructions that can be implemented by a computer system or a computer network to implement a method according to one of the embodiments.

Drawings

Further optional details and features of the invention emerge from the following description of preferred embodiments, which are schematically illustrated in the drawings.

The figures show:

fig. 1 shows a schematic view of a sensor system according to the invention according to a first embodiment;

fig. 2 shows a perspective view of a sensor system according to the invention according to a first embodiment;

fig. 3a and 3b show a top view or schematic view of a coil arrangement in combination with a sensor system according to the invention according to a first embodiment; and

fig. 4 shows a schematic view of a sensor system according to the invention according to a second embodiment.

Detailed Description

Fig. 1 shows a schematic view of a sensor system 110 according to the invention according to a first embodiment. The sensor system 110 is provided for determining at least one rotational characteristic of a rotating element 114 rotating about at least one axis of rotation 112. The sensor system 110 can be provided, in particular, for use in a motor vehicle. The sensor system 110 can be provided, in particular, for detecting at least one rotational characteristic of a camshaft. For example, the sensor system 110 may be arranged to detect the angular position of a camshaft. Correspondingly, the rotary element 114 can be, for example, a shaft. In the case of the permanently excited synchronous machine shown, the shaft may carry permanent magnets 116. The stator coil sets 118 may be arranged cylindrically around the permanent magnets 116. The output (Abtrieb) may be arranged in the negative Z-direction and is not further shown. On the side opposite the output, a B-bearing 120 may be arranged, which receives the axis 114. The B-bearing 120 may be coupled to a B-bearing shield 122. The sensor system 110 has at least one inductive position sensor 124. Inductive position sensor 124 may be disposed on circuit carrier 125. For example, the circuit carrier 125 can have a printed circuit board which surrounds the rotary element 114 in a circular ring shape or is arranged on the end side opposite the rotary element 114 and covers an angular range of 360 °, for example. The B-bearing 120 may be coupled to a B-bearing shield 122 that holds an inductive position sensor 124. The sensor system 110 has at least one sensor wheel 126 that can be coupled to the rotating element 114. A sensing wheel 126 may be disposed between the B-bearing 120 and the inductive position sensor 124, the sensing wheel being connected to the shaft at an axial end and rotating with the shaft. The inductive position sensor 124 may have a packaging. The packaging may allow the inductive position sensor 124 to be provided with a chip protection (Spanschutz) and to ensure a sufficiently high mechanical strength. The wrapping may be achieved by one or more of the following methods: direct injection molding, transfer molding by means of thermosetting plastics (transfermolding), thermoplastic injection or casting. The packaging may completely or partially enclose all components of the inductive position sensor 124. The packaging may have at least one connecting element, preferably a hole and/or a groove, through which the inductive position sensor 124 may be fastened to the B-bearing shield 122, for example by means of a screw connection. Alternatively or additionally, the inductive position sensor 124 may also be mounted to the B-bearing shield 122 by means of a clip, adhesive connection, or another method. In principle, the structure can also be mounted on the other side (a-bearing).

The sensor system 110 also has at least one temperature sensor 128, which is provided to detect at least one temperature of the rotating element 114. For example, the temperature sensor 128 may be provided for detecting the temperature by means of at least one mechanical contact with the test body, in particular the rotary element 114 and/or the sensor wheel 126 and/or the permanent magnet 116. The temperature sensor 128 has a temperature sensor element 129. The temperature sensor element 129 is, for example, an NTC element. The temperature sensor element 129 can be mounted on the rotating element 114. In particular, the temperature sensor element 129 can be integrated into the rotary element 114. As shown in fig. 1, the temperature sensor element 129 may be arranged on the rotating element 114 or in the rotating element 114 in the vicinity of the permanent magnet 116. For example, the temperature sensor element 129 is arranged on the rotary element 114 or in the rotary element 114 between the permanent magnet 116 and the sensor wheel 126, seen in the axial direction with respect to the axis of rotation 112. In principle, the temperature sensor element 129 can be arranged at any point of the rotating element 114 which, during operation, represents a particularly hot region or hot spot, in order to be able to achieve a convincing temperature detection.

The sensor system 110 has at least one evaluation unit 130. For example, inductive position sensor 124 may be connected to analysis processing unit 130 by an optional cable 132. The analysis processing unit 130 may be arranged on the circuit carrier 125. Alternatively, the evaluation unit 130 is arranged spatially separate from the circuit carrier 125. The analysis processing unit 130 may provide a voltage supply for the inductive position sensor 124. The evaluation unit 130 can receive the output signals of the inductive position sensor 124 and calculate the rotor position and the rotor temperature from these output signals. The inductive position sensor 124 may have at least one contact element to which the cable 132 may be secured. The contact elements can be holes for impact contacts (Rammkontakt), soldered plugs or pads, by means of which the cable 132 can be connected to the circuit carrier 125 by means of a soldering process.

The evaluation unit 130 is provided for generating at least one first signal 134 having at least one information about the detected temperature and at least one second signal 136 having at least one information about the rotation characteristic. For example, one or more electronic connections may be provided for this purpose between the analysis processing unit 130 and the temperature sensor 128 and/or the inductive position sensor 124. For example, the analysis processing unit 130 may comprise at least one data processing device, such as at least one computer or microcontroller. The data processing device can have one or more volatile and/or nonvolatile data memories, wherein the data processing device can be configured, for example, by programming techniques in order to actuate the inductive position sensor 124. The signal evaluation in the first evaluation unit 130 can be carried out in such a way that the evaluation unit 130 evaluates all signals received from the temperature sensor 128 and the inductive position sensor 124 and converts these signals into two output signals, namely a first signal 134 and a second signal 136. The first signal 134 may be representative of temperature and the second signal 136 is representative of a rotational characteristic, such as a rate of rotation. The first and second signals 134, 136 may both be analog, both digital, or one analog and one digital. Preferably, the first signal 134 and the second signal 136 can be transmitted via a common line to a sensor signal receiver, such as a motor control or power electronics. Alternatively, the first signal 134 and the second signal 136 may be transmitted through separate lines.

Fig. 2 shows a perspective view of a sensor system 110 according to the invention according to a first embodiment. The inductive position sensor 124 has at least one coil arrangement 138. The coil arrangement 138 is arranged on the printed circuit board 125. The coil arrangement 138 may comprise, inter alia, at least one position sensor excitation coil and at least two position sensor receiver coils. The temperature sensor 128 has a transmitter unit 140 with at least one transmitter coil 142. The transmitter unit 140 is an inductive transmitter unit, in particular an RFID reader. The temperature sensor 128 also has a receiver unit 144 with at least one receiver coil 146. The receiver unit 144 is an inductive receiver unit, in particular an RFID transponder. The inductive position sensor 124 and the transmitter unit 140 can be arranged together on the circuit carrier 125. The transmitter coil 142 faces and is preferably opposite the receiver coil 146. The receiver unit 144 is connected to the sensor wheel 126. In particular, the receiver coil 146 is arranged coaxially with the sensor wheel 126. The transmitter unit 140 is designed to inductively power the receiver unit 144. The receiver unit 144 is connected to the temperature sensor element 129. The receiver unit 144 is designed to inductively transmit the signal of the temperature sensor element 129 to the transmitter unit 140. The position sensor excitation coil of the position sensor 124 may also simultaneously serve as the transmitter coil 142, especially if the same carrier frequency is used.

The analysis processing unit 130 comprises a first analysis processing circuit 148 for generating the first signal 134 and a second analysis processing circuit 150 for generating the second signal 136. The first analysis processing circuit 148 may be separate from the second analysis processing circuit 150. It is expressly emphasized, however, that the first evaluation circuit 148 may be integrated with the second evaluation circuit 150 and may be arranged, for example, as an integrated circuit on the circuit carrier 125. The second evaluation circuit 150 is provided for supplying an excitation signal to the position sensor excitation coil of the coil arrangement 138. The second evaluation circuit 150 can be provided for processing the signals generated by the position sensor receiver coil and providing them as output signals, for example, to the evaluation unit 130.

The first analysis processing circuit 148 also comprises a part of the electronics for operating the transmitter unit 140 and for supplying the transmitter unit 140 with electrical energy. Another part for operating or controlling the receiver unit 144 is part of the sensor element of the temperature sensor 128 and can be associated with or connected to the rotor or sensor wheel 126. The temperature sensor 128 and the inductive position sensor 124 may have the same or different operating frequencies. Preferably, the position sensor 124 operates at an operating frequency in the range of about 2 to 20MHz and preferably 2.5 to 7.5 MHz. The RFID portions of the location sensor 124 and the temperature sensor 128 preferably operate at different operating frequencies. However, it is expressly emphasized that the same operating frequency may also be used for the RFID portions of the location sensor 124 and the temperature sensor 128.

With this structure, the air transformer is constructed to some extent. Both on the stator side and on the rotor side, an electronic evaluation module is required as part of the first evaluation circuit 148, which can be placed either on the same carrier (for example, the circuit carrier 125) or on a further carrier. The opposing arrangement of the transmitter coil 142 and the receiver coil 144 has the following advantages: communication is maintained permanently even at high rotational speeds. With this structure, the air transformer is constructed to some extent.

In accordance with the embodiment shown, a transmitter unit 140, including a transmitter coil 142, is combined as an RFID reader with the sensor electronics of the coil arrangement 138 and the position sensor 124 on the motor stator. The illustrated coaxial arrangement of the RFID transmitter coil 142 and the coil arrangement 138 of the position sensor 124 is particularly advantageous here. A receiver unit 144 as an RFID transponder is combined with the sensor wheel 126 of the position sensor 124 on the motor rotor. The coaxial arrangement of the RFID receiver coil 146 and the sensing wheel 126 is particularly advantageous.

For illustration purposes, fig. 3a and 3b show a top view or a schematic illustration of the coil arrangement 138 or its combination with the sensor system 110 according to the invention according to the first embodiment in a possible configuration variant. In the sensor system 110 of the first embodiment, the coil arrangement 138 of the position sensor 124 and the transmitter coil 142 of the RFID reader 140 are configured in a circular shape. In particular, the coil arrangement 138 and the transmitter coil 142 are arranged completely circularly on the circuit carrier 125. The circuit carrier 125 can also be configured to be round. The transmitter unit 140 or the transmitter coil 142 may be arranged outside the coil arrangement 138 of the position sensor 124, as shown in fig. 3 a. Alternatively, the transmitter unit 140 or the transmitter coil 142 may be arranged inside the coil arrangement 138 of the position sensor 124, as shown in fig. 3 b.

Fig. 4 shows a top view or a schematic illustration of a coil arrangement 138 or a combination thereof with a sensor system 110 according to the invention according to a second embodiment. Only the differences from the sensor system 110 of the first embodiment are described below and identical or comparable components or features are provided with the same reference numerals. In the sensor system 110 of the second embodiment, the coil arrangement 138 and the transmitter coil 142 are configured in the shape of a circle segment. In particular, the coil arrangement 138 and the transmitter coil 142 are circle segment-shaped and are therefore arranged on the circuit carrier 125 only as a part of a complete circle, for example in the form of a quarter circle. The circuit carrier 125 can also be embodied in the form of a circle segment, for example in the form of a quarter circle.

Each of the foregoing embodiments of the sensor system 110 may be modified as follows. The transmitter unit 140 and the receiver unit 144 may be configured to detect at least another physical characteristic of the rotating element 114. For example, the electronics components of the transmitter unit 140 and the receiver unit 144 are used to measure the physical measured variable with the aid of an acceleration sensor, a strain gauge or the like. As described above, the sensor system 110 can in principle be mounted on the end side on the rotary element 114 and thus allows a so-called axial scanning. Alternatively, the sensor system 110 may comprise or enclose a rotating element and thus allow a so-called radial scanning. Depending on the application, sensor arrangements with axial scanning or radial scanning are conceivable in which the rotor part of the sensor system surrounds the stator part, for example if the stator part is arranged inside a rotor embodied as a hollow shaft. The transmitter unit 140 or the transmitter coil 142 may be arranged axially offset from the position sensor 124 or its coil arrangement 138 and thus laterally. In addition to the angular position of the rotating element 114 (e.g., a rotor position sensor for a rotor shaft), the position sensor 124 may be implemented for detecting translational movement, such as a linear displacement sensor. For rotor temperature detection, 3 elements are required: a receiving coil, analysis processing electronics, and a sensor. These 3 elements may be arranged at different positions. Preferably, only the sensors (i.e. the position sensor 124 and the temperature sensor 128) should be arranged at the hottest part of the rotor, while the evaluation electronics and the receiver coil 146 are placed in the region of the cooler end side of the rotor. Illustratively (and possibly advantageously), the coil system (stator part) as well as the sensor wheel 126 and the RFID coil 144 (rotor part) are implemented as conductor paths or metallization surfaces of a circuit carrier (illustratively 125 for the stator part). Furthermore, other types of implementation of the stator part and the rotor part are also conceivable, which enable the required electromagnetic interaction. Generally to conductor paths and metallization planes on or at a dielectric carrier. A suitably shaped metallized surface (sensor wheel structure) of a dielectric carrier, which may be a printed circuit board, for example, may also be used as the sensor wheel 126. On the rotor (possibly a common carrier) the following can be integrated/assembled: the sensing wheel structure, the RFID receiver antenna 146, the associated RFID electronics and possibly further electronics components, for example for one or more (temperature) sensors.

The present invention relates to sensor structures and is easy to validate. The verification can be done by observing or analyzing the stator part as well as the rotor part of the sensor system. The measurement of electromagnetic vibrations in the vicinity of the sensor system and, if necessary, the measurement of electrical signals can be taken into account for support.

Claims

1. A sensor system (110) for determining a temperature and at least one rotational characteristic of a rotating element (114) rotating about at least one axis of rotation (112), the sensor system comprising:

at least one temperature sensor (128) which is provided for detecting at least one temperature of the rotating element (114), wherein the temperature sensor (128) has a temperature sensor element (129), a transmitter unit (140) having at least one transmitter coil (142) and a receiver unit (144) having at least one receiver coil (146), wherein the temperature sensor element (129) and the receiver unit (144) can be mounted on the rotating element (114), wherein the receiver unit (140) is designed to inductively transmit a signal of the temperature sensor element (129) to the transmitter unit (144);

at least one inductive position sensor (124) which is provided for detecting at least one piece of information about a rotational characteristic of the rotating element (114), and

at least one evaluation unit (130) which is provided to generate at least one first signal (134) having at least one item of information about the detected temperature and at least one second signal (136) having at least one item of information about the rotational characteristic.

2. Sensor system according to the preceding claim, wherein the transmitter unit (140) is an inductive transmitter unit (140), in particular an RFID reader, wherein the receiver unit (144) is an inductive receiver unit (144), in particular an RFID transponder.

3. Sensor system according to one of the preceding claims, wherein the inductive position sensor (124) and the transmitter unit (140) are arranged together on a carrier, in particular a circuit carrier (125).

4. The sensor system according to any one of the preceding claims, wherein the transmitter coil (142) is directed towards the receiver coil (146), in particular opposite the receiver coil.

5. The sensor system (110) according to any one of the preceding claims, further comprising at least one sensor wheel (126) connectable with a rotational element (114) rotatable around the rotational axis (112), wherein the receiver unit (144) is connected with the sensor wheel (126).

6. The sensor system according to the preceding claim, wherein the receiver coil (146) is arranged coaxially with the sensor wheel (126).

7. The sensor system (110) according to any one of the preceding claims, wherein the inductive position sensor has at least one coil arrangement (138), wherein the coil arrangement (138) comprises in particular at least one position sensor excitation coil and at least two position sensor receiver coils, wherein the transmitter coil (142) is arranged coaxially to the coil arrangement (138).

8. Sensor system according to the preceding claim, wherein the coil arrangement (138) and/or the transmitter coil (142) is configured in a circular or circle segment shape.

9. The sensor system (110) according to any one of the preceding claims, wherein the sensor system (110) is mountable on an axial end of the rotating element (114).

10. The sensor system (110) according to any one of the preceding claims, wherein the transmitter unit (140) is arranged inside the position sensor (124), outside the position sensor (124) or axially offset from the position sensor (124).