Device for determining sensor values ​​and control unit for controlling at least one drive component of a vehicle

Abstract

Device (100) for determining sensor values ​​(T1, T2, T3), comprising: - at least one signal generator (10) for generating input signals, - a first branch (Z1), wherein the first branch (Z1) has at least one first filter element (21) and at least one first sensor (31), - at least one further branch (Z2, Z3), wherein the at least one further branch (Z2, Z3) has at least one further filter element (22, 23) and at least one further sensor (32, 33), - at least one measuring element (40) for tapping output signals, wherein the first branch (Z1) and the at least one further branch (Z2, Z3) are arranged in a parallel circuit, wherein the at least one signal generator (10) is connected upstream of the parallel circuit, wherein the at least one measuring element (40) is connected downstream of the parallel circuit, wherein the device (100) is configured to perform the following steps: - generating (S1) at least one filter-specific input signal (f1,f2, f3),- Tapping (S2) at least one associated output signal (i1, i2, i3),- Determining (S3) at least one sensor value (T1, T2, T3) for at least one of the sensors (31, 32, 33) as a function of the at least one filter-specific input signal (f1, f2, f3) and the associated at least one output signal (i1, i2, i3).,

Description

The invention relates to a device for determining sensor values ​​and a control unit for controlling at least one drive component of a vehicle. The present invention and the underlying problem are explained with regard to its use in automotive technology, but are of course applicable to any field of application. Hybrid and electric vehicles typically incorporate one or more inverters, such as pulse-width modulated (PWM) inverters. An inverter, for example, converts direct current (DC) from a vehicle's high-voltage battery into alternating current (AC) to power an electric motor. The inverter can therefore be a drive component of the vehicle. To protect the inverter from overheating, a temperature sensor may be used. Temperature monitoring and control of the inverter are often handled by a control unit. For signal conversion between an analog temperature sensor and the control unit, an analog-to-digital converter (ADC) and a digital-to-analog converter (DAC) are used for each temperature sensor. These are, in turn, connected to at least one pin of a microcontroller within the control unit for signal transmission.Due to increased demands in temperature measurement, a large number of temperature sensors are needed to accurately map, for example, the temperature field of the inverter. At the same time, the number of pins on a microcontroller is limited. This, in turn, necessitates the use of costly workarounds such as analog multiplexing to enable the evaluation of a large number of temperature sensors despite the limited number of pins. US 10 739 210 B2 relates to a sensor for measuring the temperature of a fluid in a container, as well as to a temperature controller and a system. JP 5 545 258 B2 relates to a temperature measuring device used to measure the temperature of an object. A vehicle battery is given as an example of an object. The temperature measuring device can comprise a variety of sensors, which are, for example, arranged at different locations on the battery. DE 10 2011 078 698 B3 relates to a circuit arrangement for measuring current, a control system with a circuit arrangement and a method for measuring current. DE 10 2016 225 907 A1 relates to a method for eliminating a baseline drift of a recorded measurement signal and a filter device for eliminating a baseline drift of a recorded measurement signal. The technical problem is to create a device for determining sensor values ​​and a control unit for controlling at least one drive component of a vehicle, which enable fast and cost-effective determination of sensor values ​​with minimal installation space requirements. The solution to the technical problem is provided by the articles with the features of the independent claims. Further advantageous embodiments of the invention are described in the dependent claims. A device for determining sensor values ​​is proposed, comprising: - at least one signal generator for generating input signals, - a first branch, wherein the first branch has at least one first filter element and at least one first sensor, - at least one further branch, wherein the at least one further branch has at least one further filter element and at least one further sensor, - at least one measuring element for tapping output signals, wherein the first branch and the at least one further branch are arranged in a parallel circuit, wherein the at least one signal generator is connected upstream of the parallel circuit, and wherein the at least one measuring element is connected downstream of the parallel circuit, the device being configured to perform the following steps: - generating at least one filter-specific input signal, - tapping at least one associated output signal.- Determine at least one sensor value for at least one of the sensors as a function of the at least one filter-specific input signal and the associated at least one output signal. The device utilizes the technical effect that the branches of the parallel circuit can each be selectively addressed using the filter-specific input signal. This ensures that the input signal is routed through the sensor of the respective addressed branch, and the resulting output signal thus relates to the sensor located in that specific branch. This allows for fast and reliable determination of the sensor values. Furthermore, only one downstream measuring element is required to tap the output signal needed to determine the sensor values. This reduces component costs and installation space requirements. Based on the tapped output signal, a current sensor value for the respective sensor can be determined, for example, by exploiting physical relationships. The generation of at least one filter-specific input signal can be achieved using at least one signal generator. The input signal is, in particular, an electrical voltage signal, such as an alternating voltage signal. The amplitude of the input signal can, for example, be 12 volts. The signal generator can generate the input signal with, for example, a filter-specific frequency, filter-specific amplitude, and / or filter-specific waveform. The signal generator can, for example, generate the input signal with a frequency from a range of 10 Hz to 20 kHz. The signal generator can, in particular, generate input signals in various waveforms, such as sine, square, and sawtooth waves. The signal generator can, in particular, generate the input signals with frequency modulation and / or amplitude modulation. For example, several input signals with different frequencies can be generated in a single sweep.The sweep function allows for particularly fast stimulation with different frequencies. The filter-specific input signal has, in particular, at least one property that is matched to a filter property of at least one filter element. For example, a frequency and / or amplitude of the filter-specific input signal can be matched to a passband of the at least one filter element. In this way, it can be ensured, for example, that the filter-specific input signal can pass through at least one filter element, e.g., the first filter element, and thus also through the associated sensor of the addressed branch. Naturally, the at least one filter-specific input signal can also be matched to at least one property of the remaining filter elements. In this way, it can be ensured, for example, that the filter-specific input signal cannot pass through the remaining filter elements.For this purpose, electrical properties of the respective filter element can of course be known in advance, such as the resistance, inductance, and / or capacitance values ​​of one or more components integrated into the filter element. The filter-specific input signal makes it possible, in particular, to uniquely assign a specific sensor value to one of the sensors. The first and / or subsequent filter elements can be configured as, for example, a low-pass filter, high-pass filter, band-pass filter, or all-pass filter. Each filter element can comprise, for example, one or more resistors, one or more inductors, and / or one or more capacitors. Each filter element can affect the amplitude and / or phase of the input signal and thus influence the corresponding output signal. In other words, each filter element can filter the input signal. The at least one first sensor and / or the at least one further sensor can be, for example, resistive, inductive, capacitive, piezoelectric, photoelectric, and / or electromagnetic. A sensor can, for example, be a resistive temperature sensor, such as an NTC or PTC resistor. In particular, at least one first sensor value can be determined for the at least one first sensor and at least one further sensor value for the at least one further sensor. The sensor value can, for example, be a resistance value, inductance value, capacitance value, and / or voltage value of the respective sensor, or include such a value. In particular, the sensor value can include a current state variable for the respective sensor or be assigned to such a state variable, for example, by means of a known assignment, such as assigning a sensor value of 500 ohms to a temperature of 20 °C. In this way, the device can, for example,A temperature field around an inverter can be monitored by sensors. The state variables assigned to the sensors can include, for example, temperature, energy, volume, mass, and pressure. In particular, the at least one first sensor is connected in series with the first filter element. In particular, the at least one first sensor is connected downstream of the first filter element. In particular, the at least one further sensor is connected in series with the further filter element. In particular, the at least one further sensor is connected downstream of the further filter element. This results in the effect of the respective sensor on the filter-specific properties, especially the filter-specific cutoff frequency, of the respective filter element being particularly low. At least one associated output signal can be accessed using the at least one measuring element. The output signal can, in particular, be a current flowing through the device. The output signal can also comprise an electrical voltage signal, such as an AC voltage signal. The output signal can be modified relative to the input signal depending on the filter elements. For example, the amplitude or phase of the output signal—e.g., due to filtering by the filter elements—can be modified relative to the amplitude and / or phase of the input signal. An associated output signal refers, in particular, to an output signal that corresponds to a filter-specific input signal. The at least one measuring element can, for example, comprise a voltmeter or ammeter. The measuring element can, for example, comprise a measuring resistor. The output signals can, for example, be accessed across the measuring resistor. The device can include at least one control unit. The control unit can, for example, be designed as or incorporate a microcontroller. The control unit can be connected to the at least one signal generator to, for example, define characteristics such as the frequency and / or amplitude of the filter-specific input signal. The control unit can be connected to the at least one measuring element to, for example, evaluate the tapped output signal. Determining the sensor values ​​can, for example, be done using the at least one control unit. However, determining the sensor values ​​can, of course, also be done using the at least one measuring element. The measuring element and / or signal generator may also include an analog-to-digital converter and / or a digital-to-analog converter to convert analog signals into digital signals and vice versa. This simplifies communication with, for example, a digital control device. Determining sensor values ​​can involve, for example, evaluating a physical relationship between the filter-specific input signal, the corresponding measured output signal, and the sensor value. For instance, a current sensor value from at least one sensor can be determined assuming that the filter-specific input signal was only passed through one of the parallel branches, because, for example, the other filter elements blocked the input signal. This means the total current will flow almost entirely through the sensor whose branch was activated. Using the measuring element downstream of the sensor, the output signal can be measured as a total current. If the sensor is resistive, the voltage drop across the sensor will be approximately equal to the voltage of the input signal, since the filter element allows the input signal to pass through almost unimpeded. The sensor value, here, for example...A resistance value can therefore be determined in accordance with Ohm's law as a ratio between the voltage of the filter-specific input signal and the total current tapped as the output signal. In one embodiment, the at least one first filter element is configured to allow at least one first filter-specific input signal to pass through, while the at least one further filter element is configured to attenuate the at least one first filter-specific input signal. In this way, the first filter-specific input signal is effectively routed through the first branch and thus through the at least one first sensor. This increases the accuracy in determining the sensor value for the first sensor. Determining the at least one sensor value for the at least one first sensor is performed, in particular, as a function of the at least one first filter-specific input signal and the associated at least one output signal. The filter elements can, in particular, have different cutoff frequencies or passbands. The at least one first filter-specific input signal can, for example, be...generated with a frequency from a passband of the first filter element, wherein the frequency of the first filter-specific input signal is not contained in a passband of the further filter element. In one embodiment, the at least one further filter element is configured to allow at least one further filter-specific input signal to pass through, wherein the at least one first filter element is configured to attenuate the at least one further filter-specific input signal. In this way, the further filter-specific input signal is effectively routed through the further branch and thus through the at least one further sensor. This increases the accuracy in determining the sensor value for the further sensor. Determining the at least one sensor value for the at least one further sensor is performed, in particular, as a function of the at least one further filter-specific input signal and the associated at least one output signal. The at least one further filter-specific input signal can, for example, be...generated with a frequency from a passband of the further filter element, wherein the frequency of the further filter-specific input signal is not contained in a passband of the first filter element. In one embodiment, each filter element has a filter-specific passband, wherein the passbands are distinct from one another, and the generation of the at least one filter-specific input signal depends on the respective passband. In this way, it can be ensured that the filter-specific input signals are uniquely assigned to a filter element. In one embodiment, the determination of at least one sensor value for at least one of the sensors is carried out using a device-specific reference characteristic map. This allows coupling effects, such as the influence of one filter element on another filter element in a different branch, to be taken into account when determining the sensor values. This increases the accuracy of the sensor value determination. The device-specific reference characteristic map is known, for example, from preliminary tests or a simulation. Specifically, the determination of at least one sensor value for each sensor is carried out using the device-specific reference characteristic map. In one embodiment, at least one filter element is designed as a multi-stage element, with several filter elements connected in series within the at least one multi-stage element. This results in a more precise filtering behavior, as the multi-stage design increases, for example, the slew rate of the filter element. In other words, the transition from a passband to a blockband is more abrupt in the multi-stage filter element. A filter element can be designed, for example, as an RC element, an LC element, or an RL element, where R denotes a resistor, C a capacitor, and L an inductor. In one embodiment, the device includes a control unit, the control unit being connected to the at least one signal generator via a first interface and to the at least one measuring element via a second interface. In this way, the control unit only needs to provide two interfaces to be connected to the signal generator and the measuring element. The first interface and / or the second interface can, for example, be configured as a pin of a microcontroller of the control unit. In one embodiment, at least one filter-specific input signal is generated based on at least one previously determined sensor value. This allows for the consideration of effects that a sensor value might have on, for example, the filtering behavior of the filter elements, when generating the filter-specific input signal. This enables a more precise determination of the sensor value. For instance, a previously determined sensor value might slightly shift the passband of the first sensor. By taking the previously determined sensor value into account, the filter-specific input signals to be generated can be, for example, produced at a frequency that lies within the shifted passband. The relationship between the previously determined sensor value and, for example, the shifted passband, may be known from prior experiments.The at least one previously determined sensor value can in particular be a sensor value determined immediately beforehand from the at least one first sensor and / or from the at least one further sensor. In one embodiment, the at least one filter-specific input signal is a square wave. This makes it particularly easy to generate the filter-specific input signal, for example, if the signal generator is controlled by a digital control unit. A further proposal is a control unit for controlling at least one drive component of a vehicle, wherein the control unit comprises at least one device according to an embodiment described in this disclosure, and wherein the control unit generates at least one control variable for controlling the at least one drive component of the vehicle as a function of at least one sensor value determined by means of the at least one device. By generating the control variable, for example, an operating mode of the drive component of the vehicle can be adapted as a function of the determined sensor value. The operating mode of the at least one drive component can, for example, be adapted if at least one specific sensor value, which can, for example, represent a current temperature of the drive component, meets a threshold criterion. For example, a state variable such as, for example,The temperature of at least one drive component is monitored by sensors. The drive component can be activated, in particular, if the sensor reading exceeds a predefined threshold. The control command can, for example, be configured to switch off the at least one drive component, especially if the previously described threshold criterion is met. In this way, the drive component can be protected from overheating, for example. The at least one drive component could, for example, be a pulse inverter of the vehicle. The vehicle could, for example, be an electric or hybrid vehicle. The control unit can be configured, in particular, to perform one or more of the steps described in this disclosure. The technical effects and advantages described in this disclosure for the device naturally also extend to the control unit and vice versa. The invention is explained in more detail with reference to exemplary embodiments. The figures show: Fig. 1 a schematic representation of an embodiment of a control unit with a device, Fig. 2 a schematic flowchart of a sequence of steps, and Fig. 3 a schematic representation of a device-specific reference characteristic map. In the following, identical reference symbols denote elements with the same technical characteristics. Fig. 1 shows a schematic representation of a control unit 200 for controlling, for example, a drive component 60 of an electric vehicle (not shown), which is designed as a pulse inverter. The control unit 200 comprises a device 100. The control unit 200 and / or the device 100 can, for example, be supplied with energy from the vehicle's electrical system (not shown). The control unit 200 generates at least one control variable K to control the drive component 60 as a function of at least one sensor value determined by the device 100. The device 100 for determining sensor values ​​comprises the components described below: A signal generator 10 serves to generate at least one filter-specific input signal f1. The filter-specific input signal f1 can, for example, be a rectangular AC voltage signal with a filter-specific frequency. A first branch Z1, designed as an electrical conductor, and two further branches Z2, Z3, also designed as electrical conductors, are connected to the signal generator 10. The branches Z1, Z2, Z3 are arranged in parallel. Each branch Z1, Z2, Z3 has a filter element 21, 22, 23. A sensor 31, 32, 33, designed as a resistive resistor, is connected downstream of each filter element 21, 22, 23. A measuring element 40 for tapping at least one output signal i1 corresponding to the input signal f1 is connected downstream of the branches Z1, Z2, Z3.For this purpose, the measuring element 40 includes a measuring resistor 41 and a voltmeter 42. The grounding of the device 100 or of various components of the device 100 is indicated by G. The filter elements 21, 22, 23 are multi-stage. In each multi-stage filter element 21, 22, 23, two filter elements F1, ..., F6, configured as RC circuits, are connected in series. Each RC circuit is configured as a low-pass filter and includes a resistor R1, ..., R6 and a capacitor C1, ..., C6. Due to the multi-stage design, the transition from passing an input signal to blocking an input signal is very abrupt in each filter element 21, 22, 23. Furthermore, each filter element 21, 22, 23 has a filter-specific passband (not shown) with respect to the frequency of the input signal, whereby the passbands are distinct from one another. In this way, for example, only an input signal with a frequency within the passband of the first filter element 21 can pass through it. The generation of the at least one filter-specific input signal can therefore be dependent on the respective passband. This ensures that the filter-specific input signal f1 is uniquely assigned to the filter element 21. The device 100 further comprises a control unit 50, e.g., a microcontroller. The control unit 50 is connected to the signal generator 10 via a first interface 51, which is configured as a microcontroller pin. The control unit 50 is also connected to the voltmeter 42 of the measuring element 40 via a second interface 52, which is also configured as a microcontroller pin. Via interfaces 51 and 52, the control unit 50 can, for example, specify the frequency f1 of the filter-specific input signal and receive the corresponding output signal i1 from the measuring element 40 for evaluation. Fig. 2 shows a schematic flowchart of a sequence of steps. The control unit 200 with device 100 shown in Fig. 1 is configured to perform the steps described below. In step S1, a filter-specific input signal f1 is generated, for example, by means of the signal generator 10. A frequency of the filter-specific input signal f1 corresponds to a frequency that is not filtered by the first filter element 21 and therefore passes through it almost undamped. The filter-specific input signal f1 can be specified, for example, by the control unit 50 (see Fig. 1). The filter elements 22, 23 can be configured to prevent the filter-specific input signal f1 from passing through, i.e., to attenuate it significantly. In this way, the filter-specific input signal f1 is only passed through the first branch Z1. In step S2, for example, a corresponding output signal i1 is tapped using the measuring element 40. The tapped output signal i1 can, for example, indicate the current flowing through the measuring resistor 41. The tapped output signal i1 can be transmitted to the control unit 50 for evaluation (see Fig. 1). Assuming that the filter-specific input signal f1 has only passed through the first branch Z1, the output signal i1 can be used to determine a sensor value for the first sensor 31. In step S3, for example, a sensor value for the first sensor 32 is determined by the control unit 50 depending on the filter-specific input signal f1 and the associated output signal i1. The determined sensor value can, for example, indicate the current temperature of sensor 31 or be assigned to it. In step S4, for example, a control variable K can be generated using the control unit 50 as a function of the specific sensor value and output to a drive component 60 of an electric vehicle (see Fig. 1). Step S1 (and also the following steps S2 to S4) can of course be repeated with further filter-specific input signals f2, f3 in order to determine sensor values ​​for the remaining sensors 32, 33 as well. Fig. 3 shows a schematic representation of a device-specific reference characteristic map RK for the device 100 (see Fig. 1). The reference characteristic map RK is represented as a three-dimensional coordinate system, with three sensor values ​​T1, T2, T3 plotted against three frequencies f of the filter-specific input signals f1, f2, f3 and the currents i of the corresponding tapped output signals i1, i2, i3. This allows for a mapping of the three filter-specific input signals f1, f2, f3 and their corresponding output signals i1, i2, i3 to the respective sensor values ​​T1, T2, T3. Of course, this mapping is merely an example. The filter-specific input signals f1, f2, f3 are generated with the intention that only a specific branch Z1, Z2, Z3 of the device is addressed. In this way, the filter-specific input signals f1, f2, f3 can each be uniquely assigned to a specific sensor 31, 32, 33 and therefore also to a sensor value T1, T2, T3. In other words, the filter-specific input signal f1, f2, f3 is routed along a predefined path through the branches Z1, Z2, Z3 of the device 100, since the filter properties of the filter elements 21, 22, 23 are taken into account when generating the input signal f1, f2, f3. The device-specific reference characteristic map RK can be determined, for example, by means of a simulation. In this process, the filter-specific input signals f1, f2, f3 can be generated sequentially, and the corresponding output signals i1, i2, i3 can be tapped sequentially. The sensor values ​​T1, T2, T3 can be known in advance as reference values ​​within the simulation. In this way, a device-specific mapping between the filter-specific input signals f1, f2, f3, the corresponding output signals i1, i2, i3, and the sensor values ​​T1, T2, T3 can be determined for various operating points. This mapping can also be used to determine the sensor values ​​T1, T2, T3 in the non-simulated operation of the device 100. The reference characteristic map RK can be stored, for example, in the measuring element 40 and / or the control unit 50. In this way, to determine a current sensor value T1, T2, T3, the frequency of a frequency-specific input signal f1, f2, f3 can be compared with the corresponding output signal i1, i2, i3, and then the respective sensor value T1, T2, T3 can be determined using the reference field RK. Reference symbol list 10 Signal generator 21, 22, 23 Filter element 31, 32, 33 Sensor 40 Measuring element 41 Measuring resistor 42 Voltmeter 50 Control unit 51, 52 Interface 60 Drive component 100 Device 200 Control unit C1, ..., C6 Capacitor f Frequency of the input signal f1, f2, f3 Filter-specific input signal F1, ... F6 Filter element G Ground K Control variable i Current i1, i2, i3 Output signal RK Reference characteristic R1, ..., R6 Resistor S1, ... S4 Step T1, T2, T3 Sensor values ​​Z1, Z2, Z3 Branch

Claims

Device (100) for determining sensor values ​​(T1, T2, T3), comprising: - at least one signal generator (10) for generating input signals, - a first branch (Z1), wherein the first branch (Z1) has at least one first filter element (21) and at least one first sensor (31), - at least one further branch (Z2, Z3), wherein the at least one further branch (Z2, Z3) has at least one further filter element (22, 23) and at least one further sensor (32, 33), - at least one measuring element (40) for tapping output signals, wherein the first branch (Z1) and the at least one further branch (Z2, Z3) are arranged in a parallel circuit, wherein the at least one signal generator (10) is connected upstream of the parallel circuit, wherein the at least one measuring element (40) is connected downstream of the parallel circuit, wherein the device (100) is configured to perform the following steps: - generating (S1) at least one filter-specific input signal (f1,f2, f3),- Tapping (S2) at least one associated output signal (i1, i2, i3),- Determining (S3) at least one sensor value (T1, T2, T3) for at least one of the sensors (31, 32, 33) as a function of the at least one filter-specific input signal (f1, f2, f3) and the associated at least one output signal (i1, i2, i3)., Device (100) according to claim 1, characterized in that the at least one first filter element (21) is configured to allow at least one first filter-specific input signal (f1) to pass through, wherein the at least one further filter element (22, 23) is configured to attenuate the at least one first filter-specific input signal (f1). Device (100) according to claim 1 or 2, characterized in that the at least one further filter element (22, 23) is configured to allow at least one further filter-specific input signal (f2, f3) to pass through, wherein the at least one first filter element (21) is configured to attenuate the at least one further filter-specific input signal (f2, f3). Device (100) according to one of the preceding claims, characterized in that each filter element (21, 22, 23) has a filter-specific passband, wherein the passbands are different from each other, wherein the generation of the at least one filter-specific input signal (f1, f2, f3) is carried out depending on the respective passband. Device (100) according to one of the preceding claims, characterized in that the determination of the at least one sensor value (T1, T2, T3) for at least one of the sensors (31, 32, 33) is carried out using a device-specific reference characteristic map (RK). Device (100) according to one of the preceding claims, characterized in that at least one filter element (21, 22, 23) is designed in multiple stages, wherein several filter elements (F1, ..., F6) are connected in series in the at least one multi-stage filter element (21, 22, 23). Device (100) according to one of the preceding claims, characterized in that the device (100) has a control unit (50), wherein the control unit (50) is connected to the at least one signal generator (10) via a first interface (51) and the control unit (50) is connected to the at least one measuring element (40) via a second interface (52). Device (100) according to one of the preceding claims, characterized in that the generation of at least one filter-specific input signal (f1 f2, f3) is carried out depending on at least one previously determined sensor value (T1, T2, T3). Device (100) according to one of the preceding claims, characterized in that the at least one filter-specific input signal (f1, f2, f3) is a square wave signal. Control unit (200) for controlling at least one drive component (60) of a vehicle, wherein the control unit (200) comprises at least one device (100) according to one of claims 1 to 9, wherein the control unit (200) generates at least one control variable (K) for controlling the at least one drive component (60) of the vehicle as a function of at least one sensor value (T1, T2, T3) determined by means of the at least one device (100).

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