Device for emulating a high-voltage storage device and vehicle test bench

Abstract

A device for emulating a high-voltage storage device in a vehicle test bench comprises a cell emulator unit and a control and monitoring unit (14), wherein the cell emulator unit includes a temperature sensor emulation circuit comprising a primary sensor circuit (32), the primary sensor circuit (32) comprising a primary voltage divider (34), and wherein a first output voltage of the primary voltage divider (34) is adjustable via a primary pulse width modulation source (39). The cell emulator unit (20) is configured to transmit a primary voltage measurement value to the control and monitoring unit (14) via the primary voltage divider (34), and the control and monitoring unit (14) is configured to determine a temperature value of the primary sensor circuit (32) based on the transmitted primary voltage measurement value.

Description

[0001] The invention relates to a device for emulating a high-voltage storage device in a vehicle test bench and to a vehicle test bench for testing a motor vehicle, in particular a motor vehicle that is at least partially electrically powered, with such a device.

[0002] Vehicle test benches are used in the development of electrical systems for motor vehicles to verify that the various electrical components of the system interact as intended and thus protect against potential malfunctions. Such a vehicle test bench therefore encompasses a multitude of different electrical components of the respective vehicle, for example, control units and / or a low-voltage electrical system.

[0003] In the case of motor vehicles equipped with a high-voltage battery and thus an additional high-voltage network, it is necessary to also examine the interaction of the high-voltage battery with the other electrical components of the vehicle. For reasons of cost and safety, the installation of an actual high-voltage battery in the vehicle test bench is preferably avoided. Furthermore, in more advanced high-voltage battery concepts, such as module-free high-voltage batteries or so-called "cell-to-body" high-voltage batteries, in which the individual cells of the high-voltage battery are integrated into the vehicle's body structure, the actual high-voltage batteries can no longer be effectively represented in a conventional test bench.

[0004] For this reason, it is known to use an emulation device to emulate the high-voltage storage system in the test bench, with which the behavior of the cells and / or sensors of the high-voltage storage system is emulated via a cell emulation circuit, wherein the emulation device generates voltage values ​​that correspond to those of the actual high-voltage storage system. In this way, the influence of the voltages generated by the cells or associated sensors of the high-voltage storage system on the other electrical components in the vehicle test bench can be verified. For example, DE 10 2017 203 374 A1 discloses a device for simulating modular DC voltage sources comprising a plurality of partial voltage sources connected in series.Furthermore, DE 10 2010 031 884 A1 discloses a device that simulates the voltage source of a battery, in particular a high-voltage battery, in order to test a battery management system under the limit conditions of a real battery. However, existing emulation devices are not capable of accurately representing various operating scenarios of high-voltage storage systems, such as those that can occur in the operation of motor vehicles, and thus cannot be tested on a test bench. For example, there is a need to accurately represent the behavior of temperature sensors of the high-voltage storage system during a heating phase.

[0005] It is therefore an object of the invention to provide a device for emulating a high-voltage storage device that allows for greater flexibility in emulating the high-voltage storage device.

[0006] The problem is solved by a device for emulating a high-voltage storage device in a vehicle test bench, comprising at least one cell emulator unit and a control and monitoring unit, which is connected to the at least one cell emulator unit for signal transmission. The cell emulator unit has a cell emulation circuit with a cell emulation voltage divider comprising at least two resistors connected in series, wherein each of the resistors is assigned to an emulated cell of the cell emulation circuit, and the cell emulator unit is configured to transmit a voltage value per emulated cell to the control and monitoring unit by means of the cell emulation voltage divider.The cell emulator unit comprises a temperature sensor emulation circuit, which includes a primary sensor circuit. The primary sensor circuit has a primary voltage divider, and a first output voltage of the primary voltage divider is adjustable via a primary pulse-width modulation source. The cell emulator unit is configured to transmit a primary voltage measurement to the control and monitoring unit via the primary voltage divider. The control and monitoring unit is configured to determine a temperature value from the primary sensor circuit based on the transmitted primary voltage measurement.

[0007] The invention is based on the fundamental concept of being able to flexibly adjust the output voltage of the primary voltage divider by means of a voltage source whose output voltage can be adjusted via pulse-width modulation. In other words, one of the branches of the primary voltage divider is replaced by the primary pulse-width modulation source, thereby effectively adjusting the resistance of the corresponding branch of the voltage divider, which results in a changed primary output voltage. The adjustment can be achieved by changing the duty cycle of the primary pulse-width modulation source.

[0008] In this way, the temperature-dependent voltage behavior of a temperature sensor, which would be assigned to a real cell in a high-voltage storage system, can be emulated – that is, a sensor whose resistance or voltage changes depending on the temperature. Such temperature sensors are used in high-voltage storage systems to monitor cell temperature and are, for example, implemented as NTC resistors (NTC stands for "negative temperature coefficient").

[0009] The primary output voltage thus provides a primary voltage measurement value, which is transmitted from the cell emulator unit to the control and monitoring unit and serves there as the basis for determining the temperature value.

[0010] For example, the control and monitoring unit contains a data set that can be used to convert the primary voltage measurement into the temperature value, for example in the form of a conversion function such as a polynomial function or a look-up table.

[0011] The device according to the invention thus makes it possible to emulate the behavior of the high-voltage storage device during processes in which the temperature of the high-voltage storage device changes, for example during a heating process, a charging or discharging process or a driving cycle of the motor vehicle.

[0012] Each of the resistors connected in series in the cell emulation voltage divider is assigned to an emulated cell in the cell emulator unit and thus provides a voltage value in the cell emulation voltage divider that corresponds to the voltage value of a cell in the emulated high-voltage storage system. It is understood that the number of resistors in the cell emulation voltage divider is not further limited and should simply correspond to the number of cells in the high-voltage storage system to be emulated.

[0013] The temperature sensor emulation circuit can be designed for just a single emulated cell or for several of the emulated cells, for example, for all emulated cells.

[0014] The primary voltage divider can include a primary low-pass filter to smooth the first output voltage generated by the primary pulse-width modulation source. This improves the accuracy of temperature measurement in the control and monitoring unit, as the low-pass filter can be matched to the performance characteristics of the primary pulse-width modulation source.

[0015] For example, the primary low-pass filter is implemented as an RC low-pass filter. The cutoff frequency of the RC low-pass filter is specifically chosen such that the cutoff frequency of the primary low-pass filter is comparatively low, so that the fundamental frequency of the carrier frequency of the PWM signal from the primary pulse-width modulation source is filtered out, while the DC component of the PWM signal is passed through the primary low-pass filter.

[0016] The resistance value in the RC low-pass filter is specifically chosen to achieve optimized smoothing of the PWM signal while preventing an excessive increase in the minimum achievable output voltage of the primary voltage divider. For example, the RC low-pass filter has a resistance of less than 300 Ω.

[0017] The primary sensor circuit can include a relay that switches between a first and a second operating mode of the primary voltage divider. In the first operating mode, the primary pulse-width modulation source is active in the primary voltage divider, while in the second operating mode, a nominal resistor is connected instead of the primary pulse-width modulation source. In other words, either the primary pulse-width modulation source or the nominal resistor is active as part of the primary voltage divider.

[0018] The nominal resistor and the primary pulse width modulation source are located in the same branch of the primary voltage divider and are connected in parallel.

[0019] The nominal resistance has a value that corresponds to a standard temperature value, for example a temperature of 25 °C.

[0020] The relay is specifically designed to switch between the first and second operating modes depending on the power supply to the temperature sensor emulation circuit. For example, the relay is in the first operating mode when energized and in the second operating mode when de-energized. Thus, the nominal resistance is switched on when the relay is disconnected from the power supply. In this way, the second operating mode serves as a fallback mode for scenarios during operation of the device in a test bench where signal and / or power connections to the cell emulator unit are deliberately disconnected.

[0021] A relay also has the advantage that in the first operating mode, in which the primary pulse width modulation source is switched on, no or only a small voltage drop is generated by the relay, so that the PWM signal generated by the primary pulse width modulation source can be transmitted precisely and reliably, which in turn increases the accuracy in determining the temperature value.

[0022] The primary voltage divider has, in particular, two voltage tap points by means of which the primary voltage measurement value can be transferred from the cell emulator unit to the control and monitoring unit.

[0023] In another variant, the primary voltage divider is implemented redundantly. This means that the primary voltage divider has a first primary voltage divider branch and a second primary voltage divider branch, wherein the first output voltage of the voltage divider is the output voltage of the first primary voltage divider branch and a second output voltage of the voltage divider is the output voltage of the second primary voltage divider branch, wherein both the first output voltage and the second output voltage are adjustable via a pulse width modulation source, in particular via the same primary pulse width modulation source.In this case, the cell emulator unit is configured to transmit a first primary voltage measurement, associated with the first primary voltage divider branch, and a second primary voltage measurement, associated with the second voltage divider branch, to the control and monitoring unit via the primary voltage divider. The control and monitoring unit is then configured to determine a first and a second temperature value from the primary sensor circuit based on the transmitted first and second primary voltage measurements. This configuration ensures that a temperature measurement can still be obtained even if one of the primary voltage divider branches fails. This enables a particularly realistic emulation of a high-voltage storage system in a motor vehicle, where multiple temperature sensors are often used.

[0024] The control and monitoring unit can also include a low-pass filter to smooth the primary voltage measurements transmitted from the cell emulator unit to the control and monitoring unit. This further increases the reliability of the temperature measurement.

[0025] The low-pass filter of the control and monitoring unit can also be designed as an RC low-pass filter.

[0026] The low-pass filter of the control and monitoring unit and the primary low-pass filter are specifically matched to each other. For example, the low-pass filter of the control and monitoring unit has a higher resistance than the primary low-pass filter and / or a lower capacitance than the primary low-pass filter.

[0027] Furthermore, the temperature sensor emulation circuit can include a secondary sensor circuit, wherein the secondary sensor circuit has a secondary voltage divider, and wherein a first output voltage of the secondary voltage divider is adjustable via a secondary pulse-width modulation source. The cell emulator unit is configured to transmit a secondary voltage measurement to the control and monitoring unit via the secondary voltage divider, and the control and monitoring unit is configured to determine a temperature value from the secondary sensor circuit based on the transmitted secondary voltage measurement. The secondary sensor circuit provides an additional means of redundantly determining the temperature values.

[0028] The secondary voltage divider can, analogous to the primary voltage divider described above, include a secondary low-pass filter for smoothing the second output voltage generated by the second pulse width modulation source.

[0029] Similarly, the secondary voltage divider can also include a relay, analogous to the primary voltage divider described above, by means of which switching between a first operating mode of the secondary voltage divider and a second operating mode of the secondary voltage divider is possible, wherein in the first operating mode the secondary pulse width modulation source in the secondary voltage divider is active and in the second operating mode a nominal resistor is switched on instead of the secondary pulse width modulation source.

[0030] The nominal resistance of the secondary sensor circuit is, in particular, lower than the nominal resistance of the primary sensor circuit.

[0031] The nominal resistance of the secondary sensor circuit and the secondary pulse width modulation source are provided in the same branch of the secondary voltage divider and connected in parallel to each other.

[0032] The nominal resistance of the secondary sensor circuit has, in particular, a value that corresponds to a normal temperature value, for example a temperature of 25 °C.

[0033] The secondary voltage divider can also be implemented redundantly. This means that the secondary voltage divider has a first secondary voltage divider branch and a second secondary voltage divider branch, wherein the first output voltage of the secondary voltage divider is the output voltage of the first secondary voltage divider branch and a second output voltage of the voltage divider is the output voltage of the second secondary voltage divider branch, wherein both the first output voltage and the second output voltage are adjustable via a pulse width modulation source, in particular via the same secondary pulse width modulation source.In this case, the cell emulator unit is configured to transmit a first secondary voltage measurement, assigned to the first secondary voltage divider branch, and a second secondary voltage measurement, assigned to the second secondary voltage divider branch, to the control and monitoring unit via the secondary voltage divider. The control and monitoring unit is then configured to determine a first and a second temperature value from the secondary sensor circuit based on the transmitted first and second secondary voltage measurements. This configuration ensures that a temperature measurement can still be obtained even if one of the secondary voltage divider branches fails. This also enables a particularly realistic emulation of a high-voltage storage system in a motor vehicle, where multiple temperature sensors are often used.

[0034] The primary voltage divider can include a primary resistor and the secondary voltage divider a secondary resistor, where the nominal resistance of the primary resistor is greater than the nominal resistance of the secondary resistor. Thus, the resistors used in the primary and secondary voltage dividers differ. This allows for the use of different resistance-temperature and voltage-temperature characteristic curves, which can serve as the basis for determining the temperature value in the control and monitoring unit, for example, as the basis for a conversion function or a lookup table.

[0035] To further increase the variability of the device with regard to emulated operating scenarios of the high-voltage storage system, the cell emulator unit can incorporate an asymmetry circuit comprising a switchable DC-DC converter connected in parallel to one of the resistors in the cell emulation voltage divider. The DC-DC converter is configured to raise the voltage value of the emulated cell to which the parallel resistor is assigned by more than one threshold value when the DC-DC converter is switched on. In this way, the behavior of the high-voltage storage system can be emulated for scenarios in which there are deviations in the cell voltage of a cell within the high-voltage storage system.

[0036] The threshold value lies particularly in the range of 5 to 10 mV. Such a value represents a typical deviation from a target cell voltage, as is to be expected in high-voltage storage devices, so it is particularly advantageous if such behavior can be emulated by the device.

[0037] The DC / DC converter is designed to be galvanically isolated in order to ensure potential separation from the voltage supply of the cell emulation voltage divider.

[0038] The DC-DC converter can be switched on and off using a relay in the asymmetry circuit. This allows for a reliable switching between the DC-DC converter being on and off, while simultaneously minimizing contact resistance.

[0039] The object of the invention is further achieved by a vehicle test bench for testing a motor vehicle, in particular a motor vehicle that is at least partially electrically powered, comprising a device as described above.

[0040] The features and properties of the device according to the invention apply accordingly to the vehicle test bench according to the invention and vice versa, and reference is made to the previous statements.

[0041] Further features and characteristics will become apparent from the following description of exemplary embodiments, which are not to be understood in a restrictive sense, as well as from the drawings. These show: - Fig. 1 a schematic representation of a vehicle test bench according to the invention comprising a device according to the invention for emulating a high-voltage storage device with a cell emulator unit; - Fig. 2 selected parts of a cell emulation circuit of the cell emulator unit from Fig. 1; - Fig. 3 a first embodiment of a primary sensor circuit of the cell emulator unit Fig. 1; - Fig. 4 a second embodiment of the primary sensor circuit Fig. 4; - Fig. 5 a first embodiment of a secondary sensor circuit of the cell emulator unit Fig. 1; - Fig. 6 a second embodiment of the secondary sensor circuit Fig. 5; and - Fig. 7 an asymmetry circuit of the cell emulator unit Fig. 1.

[0042] Fig. Figure 1 schematically shows selected parts of a vehicle test stand 10 for testing a motor vehicle, in particular a motor vehicle that is at least partially electrically powered, specifically the electrical components of the motor vehicle.

[0043] The vehicle test stand 10 includes a device 12 for emulating a high-voltage storage device, which is connected to a control and monitoring unit 14 via signal transmission.

[0044] The control and monitoring unit 14 is in turn connected to other electrical components 16 of the motor vehicle via signal transmission in order to investigate the interaction of the device 12 and the other electrical components 16 of the motor vehicle within the vehicle test stand 10.

[0045] In Fig. Figure 1 shows only a single additional electrical component 16 for the sake of clarity. It is understood that a multitude of electrical components 16 may be present, connected to the control and monitoring unit 14, for example, components of a low-voltage electrical system.

[0046] The control and monitoring unit 14 has an evaluation unit 18, which is designed in particular in the form of a microcontroller.

[0047] The device 12 has a plurality of cell emulator units 20, each of which has a cell emulation circuit 22, each of which in turn emulates a plurality of cells of a high-voltage storage device.

[0048] In the embodiment shown, a total of twelve cell emulator units 20 are provided. It is understood that the number of cell emulator units 20 can also be higher or lower, the number of cell emulator units 20 being selected being determined in particular by the number of available connections on the control and monitoring unit 14 and / or by the number of cells of the high-voltage storage to be emulated.

[0049] Fig. Figure 2 shows selected parts of the cell emulation circuit 22 of one of the cell emulator units 20. Fig. 1.

[0050] The cell emulation circuit 22 has several resistors connected in series, of which in Fig. Figure 2 shows only the last three resistors, R16 to R18, of a total of eighteen resistors connected in series. In the illustrated embodiment, the cell emulation circuit 22 thus has a total of eighteen resistors connected in series, with each resistor being assigned to an emulated cell of the cell emulation circuit 22. It should also be understood that the cell emulation circuit 22 can have more or fewer resistors than shown. Fig. 2 shown, the number depends in particular on the total number of cells to be emulated in the high-voltage storage system and the number of cell emulator units 20.

[0051] The cell emulation circuit 22 has a voltage source 24 that supplies the series circuit of resistors of the cell emulation circuit 22 with a total voltage. This causes the series circuit of resistors to form a cell emulation voltage divider 25, so that the voltage of the respective cell emulated by the respective resistor can be emulated between the voltage tap points that are closest to each resistor in the series circuit.

[0052] For example, the voltage of the emulated cell, defined by the resistor R18, can be measured as the voltage between the voltage tap points 26 and 28.

[0053] The voltage applied by voltage source 24, as well as the number of resistors in the series circuit, depends primarily on the voltage of the cell to be emulated. For example, the voltage source applies a voltage of 73.8 V to emulate a cell voltage of 4.1 V for eighteen emulated cells.

[0054] The cell emulator unit 20 is configured to transmit the respective voltage values ​​per emulated cell within the cell emulation voltage divider to the control and monitoring unit 14, as shown in Fig. 2 is shown schematically.

[0055] Furthermore, one of the cell emulator units 20 has a temperature sensor emulation circuit 30, which serves to emulate the behavior of temperature sensors as they would be used in the emulated high-voltage storage device (see Fig. 1) NTC resistors are frequently used as temperature sensors in high-voltage storage devices; these are resistors whose value changes depending on the temperature.

[0056] It is understood that, depending on the available connections of the control and monitoring unit 14, more than one of the cell emulator units 20 may have a temperature sensor emulation circuit 30.

[0057] The temperature sensor emulation circuit 30 has a primary sensor circuit 32, which in a first embodiment is Fig. 3 is shown.

[0058] The primary sensor circuit 32 serves to emulate the behavior of a temperature sensor of a high-voltage storage device, in particular an NTC sensor, which is why in Fig. 3 the voltage tap points of the primary sensor circuit 32 are marked with “NTC+” and “NTC-”.

[0059] The primary sensor circuit 32 comprises a primary voltage divider 34, one branch of which is connected to a resistor R3 and the other branch of which, depending on the switching position of a relay 36, is connected to either a nominal resistor 38 (in Fig. 3 also referred to as R2) or a primary pulse width modulation source 39.

[0060] A first output voltage of the primary voltage divider 34 can be adjusted via the primary pulse width modulation source 39, in particular by varying the duty cycle of the primary pulse width modulation source 39. In this way, it is possible to emulate the temperature-dependent resistance of an NTC sensor using the primary voltage divider 34 and to test it within the vehicle test bench 10 in conjunction with the other electrical components 16.

[0061] The relay 36 has two switches S1 and S2, which can be switched synchronously by means of a signal connection 40, whereby one of the two switches S1 and S2 is always closed and the other of the two switches S1 and S2 is open.

[0062] The relay 36 can be used to switch between a first operating mode and a second operating mode of the primary sensor circuit 32. Fig. Figure 3 represents a state during the first operating mode in which the switch S2 is closed and thus the primary pulse width modulation source 39 in the primary sensor circuit 32 is active.

[0063] Thus, in the first operating mode, various operating scenarios of the emulated high-voltage storage device can be tested within the vehicle test bench 10 by controlling the primary pulse width modulation source 39, in particular by varying the duty cycle of the primary pulse width modulation source 39, for example a heating process of the high-voltage storage device, a charging / discharging process or a driving cycle of the vehicle.

[0064] In the second operating mode of the primary sensor circuit 32, the switch S2 of the relay 36 is open and the switch S1 of the relay 36 is closed, so that the primary pulse width modulation source 39 is switched off and the nominal resistor 38 is switched on.

[0065] The nominal resistance 38 is specifically chosen such that, in the second operating mode, the first output voltage of the primary sensor circuit 32 corresponds to a normal temperature value, for example, 25 °C. Therefore, the second operating mode represents a fallback value of the first output voltage.

[0066] For example, the primary sensor circuit 32 switches to the second operating mode when the signal terminals 40 of the relay 36 are de-energized.

[0067] It is also fundamentally possible to omit the relay 36 and have the primary pulse width modulation source 39 permanently form a branch of the primary voltage divider 34, thus eliminating the need for the reset option via the nominal resistor 38. This reduces the complexity and cost of the cell emulator unit 20.

[0068] A primary low-pass filter 42, designed as an RC low-pass filter, is arranged between the primary pulse-width modulation source 39 and the voltage tap point NTC of the primary sensor circuit 32. The primary low-pass filter 42 serves to smooth the signal generated by the primary pulse-width modulation source 39, which has a positive effect on the accuracy of the temperature emulation.

[0069] The first output voltage present at the primary sensor circuit 32 can be transmitted in the form of a primary voltage measurement value to a measuring connection 44 of the control and monitoring unit 14, which is in particular a connection of the evaluation unit 18.

[0070] A low-pass filter 46 of the control and monitoring unit 14 is located upstream of the measuring terminal 44 and serves to smooth the primary voltage measurements transmitted from the cell emulator unit 20 to the control and monitoring unit 14.

[0071] Fig. Figure 4 shows a second embodiment of the primary sensor circuit 32, which essentially corresponds to the first embodiment, so that only the differences will be discussed below. Identical reference numerals denote identical or functionally equivalent components, and reference is made to the previous explanations.

[0072] In the second embodiment, the primary sensor circuit 32 is redundantly designed and comprises a first primary voltage divider branch 48 and a second primary voltage divider branch 50.

[0073] Each of the primary voltage divider branches 48 and 50 is connected to a measuring terminal 44 of the control and monitoring unit 14 for signal transmission, so that the control and monitoring unit 14 receives and processes a first output voltage of the primary sensor circuit 32 via the first primary voltage divider branch 48 and a second output voltage of the primary sensor circuit 32 via the second primary voltage divider branch 50 in order to determine a first temperature value and a second temperature value.

[0074] Thus, on the one hand, mutual monitoring of the temperature values ​​is possible, and on the other hand, at least one temperature value can still be determined by the control and monitoring unit 14 if one of the primary voltage divider branches 48 and 50 should fail.

[0075] As in Fig. As can be seen in Figure 4, both the first primary voltage divider branch 48 and the second primary voltage divider branch are supplied with a PWM signal from the same primary pulse width modulation source 39. This simplifies the primary sensor circuit 32. However, it is also fundamentally possible for each primary voltage divider branch 48 or 50 to have its own primary pulse width modulation source 39.

[0076] In the second embodiment, a relay 36 is also provided, which can be used to switch between a first operating mode and a second operating mode of the primary sensor circuit 32, as previously described for the first embodiment.

[0077] However, the nominal resistance 38 is only half the size compared to the nominal resistance 38 of the first embodiment due to the resulting parallel connection of the resistors R1.

[0078] Fig. Figure 5 shows a first embodiment of a secondary sensor circuit 52 of the temperature sensor emulation circuit 30, which can be present and operated in addition to the primary sensor circuit 32.

[0079] The secondary sensor circuit 52 serves to emulate the behavior of an additional redundant temperature sensor of a high-voltage storage device, also in particular an NTC sensor, which is why in Fig. 5 the voltage tap points of the secondary sensor circuit are marked with “NTC+” and “NTC-”.

[0080] The secondary sensor circuit 52 comprises a secondary voltage divider 54, one branch of which is connected to resistor R3 and the other branch of which is connected, depending on the switching position of a relay 56, either to a nominal resistor 58 (in Fig. 4 (also known as R2) or a secondary pulse width modulation source 60.

[0081] The operation of the components of the secondary sensor circuit 52 is essentially analogous to the operation of the analog components of the primary sensor circuit 32, so reference is made to the previous explanations and the same component designations are used. Fig. 5 is used.

[0082] The secondary sensor circuit 52 also has a low-pass filter 55, which is arranged between the secondary pulse width modulation source 60 and the voltage tap point NTC+ of the secondary sensor circuit 52, the switches S1 and S2 of the relay 56 have signal connections 61 and the measuring connection 44 of the control and monitoring unit 14 also has a low-pass filter 65 in front of it.

[0083] It is understood, however, that the components used in the secondary sensor circuit 52 and the primary sensor circuit 32 preferably differ from one another, for example, in the values ​​of the nominal resistors 38 and 58. In this way, the secondary sensor circuit 52 exhibits a different resistance-temperature or voltage-temperature characteristic curve than the primary sensor circuit 32. Thus, the control and monitoring unit 14 can determine and compare both a temperature value based on a primary voltage measurement from the primary sensor circuit 32 and a temperature value based on a secondary voltage measurement from the secondary sensor circuit 52. Any deviations can therefore be reliably detected.

[0084] Fig. Figure 6 shows a second embodiment of the secondary sensor circuit 52, which essentially corresponds to the first embodiment, so that only the differences will be discussed below. Identical reference numerals denote identical or functionally equivalent components, and reference is made to the previous explanations.

[0085] The second embodiment of the secondary sensor circuit 52 is designed analogously to the second embodiment of the primary sensor circuit 32 (see Figure 1). Fig. 4) and has a redundantly designed secondary sensor circuit 52, which has a first secondary voltage divider branch 62 and a second secondary voltage divider branch 64.

[0086] Each of the secondary voltage divider branches 62 and 64 is connected to a measuring terminal 44 of the control and monitoring unit 14 for signal transmission, so that the control and monitoring unit 14 receives and processes a first output voltage of the secondary sensor circuit 52 via the first secondary voltage divider branch 62 and a second output voltage of the secondary sensor circuit 52 via the second secondary voltage divider branch 64 in order to determine a first temperature value and a second temperature value.

[0087] In this case, too, mutual monitoring of the temperature values ​​is possible, and at least one temperature value can still be determined by the control and monitoring unit 14 if one of the secondary voltage divider branches 62 and 64 should fail.

[0088] The same applies to the secondary sensor circuit 52: both secondary voltage divider branches 62 and 64 can be assigned the same secondary pulse width modulation source 60, or each of the secondary voltage divider branches 62 and 64 can have its own secondary pulse width modulation source 60.

[0089] Fig. Figure 7 shows an additional asymmetry circuit 66 of the cell emulator unit 20.

[0090] The asymmetry circuit 66 comprises a DC voltage converter 68, which is connected in parallel to one of the resistors of the cell emulation voltage divider 25, in the illustrated embodiment in parallel to the resistor R18, i.e. the last emulated cell in the sequence of the cell emulation voltage divider 25.

[0091] The asymmetry circuit 66 further includes a relay 70, by means of which the DC-DC converter 68 can be switched on. For this purpose, the relay 70 has switches S3 and S4, which can be synchronously closed or opened via signal terminals 72, whereby one of the switches S3 and S4 is always open while the other is closed.

[0092] In Fig. Figure 7 shows a state in which switch S3 is open and switch S4 is closed, so that the DC-DC converter 68 is not connected. Instead, the DC-DC converter 68 is galvanically isolated, so that its potential does not affect the voltage of the emulated cells of the cell emulation voltage divider 25.

[0093] When the DC-DC converter 68 is switched on, it raises the voltage across the resistor to which the DC-DC converter 68 is assigned by more than a threshold value. In this way, a cell is emulated whose voltage differs from those of the other cells emulated by the other resistors of the cell emulation voltage divider 25.

[0094] For example, the threshold value is in the range of 5 to 10 mV.

[0095] The DC-DC converter 68 has in particular a power to provide a current corresponding to a typical balancing current in a high-voltage storage device that would flow if one of the cells of the high-voltage storage device had a voltage exceeding the threshold emulated via the asymmetry circuit 66.

[0096] The signal terminals 72 of the relay are designed such that the DC-DC converter 68 is not switched on when the signal terminals 72 are de-energized. In this way, the voltages of the cell emulation voltage divider 25 fall back to a fallback value that corresponds to the normal operation of the cell emulation voltage divider 25.

[0097] Overall, the device 12 according to the invention, and thus the vehicle test bench 10 according to the invention, is characterized by a high degree of flexibility in the emulatorable scenarios of the high-voltage storage system. This makes it possible to test the interaction of the emulated high-voltage storage system with the other electrical components 16 in a particularly comprehensive manner.

Claims

[1] Device (12) for emulating a high-voltage storage device in a vehicle test bench (10), comprising at least one cell emulator unit (20) and a control and monitoring unit (14) which is connected to the at least one cell emulator unit (20) via signal transmission, wherein the cell emulator unit (20) has a cell emulation circuit (22) with a cell emulation voltage divider (25) comprising at least two resistors connected in series, wherein each of the resistors is assigned to an emulated cell of the cell emulation circuit (22), and the cell emulator unit (20) is configured to transmit a voltage value per emulated cell to the control and monitoring unit (14) by means of the cell emulation voltage divider (25), wherein the cell emulator unit (20) has a temperature sensor emulation circuit (30) comprising a primary sensor circuit (32), wherein the primary sensor circuit (32) has a primary voltage divider (34), wherein a first output voltage of the primary voltage divider (34) is adjustable via a primary pulse width modulation source (39), wherein the cell emulator unit (20) is configured to transmit a primary voltage measurement value to the control and monitoring unit (14) by means of the primary voltage divider (34), and wherein the control and monitoring unit (14) is configured to determine a temperature value of the primary sensor circuit (32) based on the transmitted primary voltage measurement value. [2] Device (12) according to claim 1, wherein the primary voltage divider (34) comprises a primary low-pass filter (42) for smoothing the first output voltage generated by the primary pulse width modulation source (39). [3] Device (12) according to claim 1 or 2, wherein the primary sensor circuit (32) comprises a relay (36) by means of which switching between a first operating mode and a second operating mode of the primary voltage divider (34) is possible, wherein in the first operating mode the primary pulse width modulation source (39) is active in the primary voltage divider (34) and in the second operating mode a nominal resistor (38) is connected instead of the primary pulse width modulation source (39). [4] Device (12) according to one of the preceding claims, wherein the primary voltage divider (34) has two voltage tap points by means of which the primary voltage measurement value can be transferred from the cell emulator unit (20) to the control and monitoring unit (14). [5] Device (12) according to one of the preceding claims, wherein the control and monitoring unit (14) has a low-pass filter (46) for smoothing the primary voltage measurements transmitted from the cell emulator unit (20) to the control and monitoring unit (14). [6] Device (12) according to one of the preceding claims, wherein the temperature sensor emulation circuit (30) further comprises a secondary sensor circuit (52), wherein the secondary sensor circuit (52) has a secondary voltage divider (54), wherein a first output voltage of the secondary voltage divider (54) is adjustable via a secondary pulse width modulation source (60), wherein the cell emulator unit (20) is configured to transmit a secondary voltage measurement value to the control and monitoring unit (14) by means of the secondary voltage divider (54), and wherein the control and monitoring unit (14) is configured to determine a temperature value of the secondary sensor circuit (52) based on the transmitted secondary voltage measurement value. [7] Device (12) according to claim 6, wherein the primary voltage divider (34) comprises a primary resistor and the secondary voltage divider (54) comprises a secondary resistor, and wherein a nominal resistance (38) of the primary resistor is greater than a nominal resistance (58) of the secondary resistor. [8] Device (12) according to one of the preceding claims, wherein the cell emulator unit (20) has an asymmetry circuit (66) comprising a switchable DC voltage converter (68) connected in parallel to one of the resistors in the cell emulation voltage divider (25), wherein the DC voltage converter (68) is configured to raise the voltage value of the emulated cell to which the parallel-connected resistor is assigned by more than a threshold value when the DC voltage converter (70) is switched on. [9] Device (12) according to claim 8, wherein the DC voltage converter (68) can be switched on by means of a relay (70) of the asymmetry circuit (66). [10] Vehicle test stand (10) for testing a motor vehicle, in particular a motor vehicle that is at least partially electrically powered, comprising a device (12) according to one of the preceding claims.

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