DE102021119956A1 - Testing of power supply paths and consumers of a vehicle - Google Patents

Abstract

The present invention relates to a method for testing at least one power supply path (1) and/or at least one consumer (3, 4, 10, 11) connected to it, wherein in the method: (a) starting from a voltage-free state, the power supply path (1 ) a voltage (U1) with a first voltage level (U1,1, U1,2, U1,3) is applied, (b) at least one electrical variable (U1, U2, I) of the power supply path (1) is measured, (c ) the at least one measured electrical variable (U1, U2, I) and/or a variable derived from it is compared with a reference, (d) if the result of the comparison indicates an error state, at least one action is triggered, (e) at least when the result of the comparison indicates an error-free state, a voltage (U1) is applied to the power supply path (1) whose voltage level (U1,2, U1,3, U1,4) is above the previous voltage level (U1,1 , U1,2, U1,3) and (f) following step tte (b) to (e) are executed again.

Description

The invention relates to a method for testing at least one power supply path and/or at least one consumer connected to it, in which method a voltage with a specific voltage level is applied to the power supply path, at least one electrical variable of the power supply path is measured, (c) the at least one measured electrical quantity and/or a quantity derived therefrom is compared with a reference and then, if the result of the comparison indicates an error state, at least one action is triggered. The invention also relates to a vehicle having a structural unit of an on-board power supply system of the vehicle with at least one variable DC-DC converter which is electrically connected on the output side to the first end of the power supply path, the vehicle being designed to carry out the method. The invention can be applied particularly advantageously to checking power supply paths of an on-board power supply system of a vehicle and consumers connected to it.

In a system with voltage supplies in the higher low-voltage range, e.g. 48 V, faults such as line breaks or arcing with uncertain damage outcome can occur on a supply line to a subsystem of the vehicle (e.g. an electric steering system or an electric braking system). The energy management of on-board power supply systems has so far not had any degree of freedom to decide how a component in the subsystem should behave when it is first switched on / booted up after starting a vehicle (also known as "First Switch to Power"). This means that the energy efficiency of the subsystems is not optimal today. Safety-relevant subsystems with safety requirements now require a separate communication line in addition to a supply line in order to be able to detect a fault in the subsystem from the outside.

DE 10 2017 210 521 A1 discloses an assembly for providing output voltages. The assembly has: at least one voltage input interface for connecting to an input voltage, a plurality of DC-DC converters, each of which is connected to the voltage input interface on the input side, a plurality of voltage output interfaces, each of the voltage output interfaces being connected to a voltage output of one of the plurality of DC-DC converters, for respective connection with a consumer not located on the assembly.

DE 10 2013 207 775 A1 discloses a device for a vehicle for detecting a fault in an electrical line between a load and a voltage source or ground, comprising: a voltage measuring device which is set up to measure voltages at at least two points of the electrical line; and an evaluation device that is set up to detect the occurrence of a fault based on voltage differences in the measured voltages. In one development, the voltage measuring device measures a voltage at a connection part of the electrical line with the load. In one development, the voltage measuring device measures a voltage or a voltage curve on a connection part of the electrical line to the voltage source that is remote from the load. In a development, the connecting part includes a plug-in connection. The evaluation device can detect the occurrence of a fault when a voltage difference exceeds a threshold value.

DE 102 03 921 A1 discloses that in a control device for components of a control device with a control part and with a power part, in which there is an operating voltage on the input side and on the output side there is a connection of the control part to a data sink and of the power part to an electrical consumer, a switching logic that depends on the level the operating voltage, on the one hand only the control part or only the power part or on the other hand the control part and the power part is activated.

DE 102 11 970 A1 discloses that in a method for adapting the power requirements of a number of electrical consumers in motor vehicle on-board networks for controlling the power consumption of a number of consumers, each of these consumers is constantly provided with information about the total electrical power available in each case. The respective consumer sets his power requirement according to this information and according to his power requirement in such a way that the total power consumed does not exceed the total power available.

According to DE 10 2019 125 293 A1 a device is used for DC voltage conversion in a vehicle electrical system with a first partial vehicle electrical system with a first partial vehicle electrical system voltage and a second partial vehicle electrical system with a second partial vehicle electrical system voltage, the device having a DISO DC voltage converter with a first input for connection to the first partial vehicle electrical system, with a second input for connection to having the second sub-board network and having an output for connection to at least one consumer and wherein the device is set up to one of the inputs to convert the applied partial vehicle electrical system voltage into the partial vehicle electrical system voltage present at the other of the inputs and to apply it to the other of the inputs.

It is the object of the present invention to at least partially overcome the disadvantages of the prior art and in particular to provide a structurally simple way of testing a power supply line of a control unit and the control unit for faults, in particular line faults.

This object is solved according to the features of the independent claims. Preferred embodiments can be found in particular in the dependent claims.

1. (a) ausgehend von einem spannungslosen Zustand an den Stromversorgungspfad eine Spannung mit einem ersten Spannungsniveau angelegt wird,
2. (b) mindestens eine elektrische Größe des Stromversorgungspfads gemessen wird,
3. (c) die mindestens eine gemessene elektrische Größe und/oder eine daraus abgeleitete Größe mit einer Referenz verglichen wird,
4. (d) dann, wenn das Ergebnis des Vergleichs einen Fehlerzustand angibt, mindestens eine Aktion ausgelöst wird,
5. (e) zumindest dann, wenn das Ergebnis des Vergleichs einen fehlerfreien Zustand angibt, den Stromversorgungspfad eine Spannung angelegt wird, deren Spannungsniveau oberhalb des vorherigen Spannungsniveaus liegt, und
6. (f) folgend die Schritte (b) bis (e) erneut ausgeführt werden.

Method for testing at least one power supply path and/or at least one consumer connected thereto, wherein in the method:

1. (a) starting from a voltage-free state, a voltage with a first voltage level is applied to the power supply path,
2. (b) at least one electrical quantity of the power supply path is measured,
3. (c) the at least one measured electrical variable and/or a variable derived therefrom is compared with a reference,
4. (d) if the result of the comparison indicates an error condition, at least one action is triggered,
5. (e) at least if the result of the comparison indicates a fault-free state, a voltage is applied to the power supply path, the voltage level of which is higher than the previous voltage level, and
6. (f) following steps (b) to (e) are performed again.

This method has the advantage that the electrical reaction for each of the levels can be measured individually due to the gradual increase in the voltage level of the voltage applied to the power supply path, and thus the good case / error-free state or the bad case / error case can be evaluated separately for each of the voltage levels. As a result, faults, in particular line faults, which may only become apparent at higher voltage levels, can be detected particularly precisely. A further advantage is that faults in the consumer can also be localized more precisely, which makes subsequent maintenance (repair, replacement, etc.) easier. In addition, the method can advantageously be implemented using conventional components and does not require any additional measuring devices. In addition, a separate communication line for externally detecting a fault in the consumer can be dispensed with.

The fact that the method is provided for testing a power supply path and/or a consumer connected to it includes that the method can only be used for testing the power supply path, for testing only the consumer or for testing the power supply path and the consumer.

Because the power supply path is connected to a load, the load can be supplied with electrical energy via the power supply path for its operation and possibly for the operation of peripheral components connected to it.

In particular, the control unit has electronics, e.g. a microcontroller, ASIC, FPGA, etc. In a further development, the electronics can be operated at the first voltage level.

The fact that a voltage is applied to the power supply path includes, in particular, that the voltage is applied to an end of the power supply path that is remote from the load (“first”). Due to the ohmic resistance of the power supply path, at least in the error-free state, there is a voltage at the load-side (“second”) end of the power supply path that is lower than the voltage applied at the first end.

In one configuration, the at least one electrical variable measured in step (b) includes or is the voltage present or set at the first end of the power supply path, the voltage present at the second end of the power supply path and/or the current flowing through the power supply path . The electrical quantity measured may correspond to a single measured value or to a value calculated from a plurality of measured values, e.g.

A derived quantity can, for example, be a difference (e.g. between the voltages present at the first and second ends of the power supply path) and/or a quotient (e.g. between the voltage present at the first end and the current) or any other combination of one or more measured electrical quantities.

The comparison with the reference in step (c) can include the measured electrical quantity (eg a single measured value or an average thereof) being compared directly with a reference.

The reference is a measure of the good or bad case or error-free case or error case. If, for example, the reference reflects the good case or the error-free state and the at least one measured electrical variable and/or the variable derived from it matches the respective reference value with sufficient accuracy, an error-free state can be assumed, otherwise an error or error state . The reference can be an individual value, in particular a threshold value, which is assumed to be in error when it is reached, fallen below or exceeded. The reference can also be a range of values (“reference range”), in which case, for example, if the measured value or the variable derived from it lies within the range of values, an error-free state is determined, otherwise an error state. In general, this can be described as checking whether the at least one measured electrical variable and/or the variable derived therefrom meets a predetermined criterion, and if this is the case, an error state or an error-free state is determined. Examples of references can be the desired current through the power supply path expected for a specific voltage level and/or a voltage difference across the power supply path or value bands expected for a specific voltage level.

The result of the comparison can be a status from the "error-free status" / "error status" group. However, the result can also be categorized into more than two states, e.g. "error-free state" / "questionable state" / "error state" or "green" / "yellow" / "red" in the manner of a traffic light switch.

If an error condition is detected, at least one action can be triggered. The at least one action can include, for example, outputting an error message, preventing a further increase in the voltage applied to the power supply path, reducing this voltage and/or switching off the load.

The increase in the voltage level occurs, in particular, step by step or abruptly. The voltage levels applied are predetermined test voltages. The respective voltage level can in particular be maintained for a predetermined period.

The method can be carried out in particular before the start of the journey (“pre-drive check”), in particular it can be used when the consumer starts up for the first time.

In one configuration, steps (e) to (f) are carried out multiple times until a maximum voltage level is reached. This has the advantage that the error can be carried out separately for several different operating scenarios with different activated operating components of the consumer (e.g. electronics, communication module, sensors, actuators, etc.), which simplifies a cause analysis.

The highest voltage level is in particular that voltage level at which the consumer and all peripheral components connected to it are in operation, are ready for operation or can be switched to be ready for operation. In particular, the highest voltage level can correspond to the nominal voltage of the associated power supply system, e.g. 12 V, 48 V, 120 V, 400 V, 800 V, etc. depending on the power supply system.

Specifically, the method performs the steps specified in the order specified.

In one configuration, the consumer is a control unit, the control unit has electronics and a communication device and is connected to at least one peripheral component that can be supplied with electrical energy via the control unit. This results in the advantage that safety-relevant subsystems of the vehicle can also be specifically tested using the method.

In one configuration, the control device and the at least one peripheral component—or components or components thereof—have at least two different voltage levels as operating or supply voltages. This achieves the advantage that at least one component is not yet put into operation at a lower voltage level and therefore advantageously also does not produce any dynamic effects that could influence the electrical variable measured in step (b). If an error state is detected, a component that is not yet in operation can also be ruled out as the cause of the error state, which simplifies troubleshooting.

In one development, the control unit has at least one supply voltage that is lower than a supply voltage of at least one peripheral component. This can be implemented, for example, in such a way that the control unit has a nominal supply voltage of between 2.5 V and 3 volts for operating at least its electronics has a communication device such as a bus interface with a nominal supply voltage between 4.5 V and 6 V, some peripheral components require a nominal supply voltage of 12 V and further peripheral components require a nominal supply voltage of 48 V. The vehicle's associated on-board power supply system is then, for example, a 48 V on-board power supply.

• - ein erstes Spannungsniveau, bei dem die Elektronik des Steuergeräts betreibbar ist, aber noch keine Kommunikationseinrichtung des Steuergeräts und noch keine Peripheriekomponente. Das erste Spannungsniveau kann z.B. in einem Bereich [2,5 V; 3 V] liegen.
• - ein zweites Spannungsniveau, bei dem die Elektronik des Steuergeräts und seine Kommunikationseinrichtung betreibbar sind, aber noch keine Peripheriekomponente.

In one configuration, the voltage level includes at least one voltage level from the group of the following voltage levels:

• - A first voltage level at which the electronics of the control unit can be operated, but still no communication device of the control unit and no peripheral component. The first voltage level can be in a range [2.5 V; 3V].
• - A second voltage level at which the electronics of the control unit and its communication device can be operated, but no peripheral components.

• - ein drittes Spannungsniveau, bei dem die Elektronik und die Kommunikationseinrichtung des Steuergeräts sowie mindestens eine Peripheriekomponente (z.B. mindestens eine Sensor) betreibbar sind, aber andere Peripheriekomponenten (z.B. Aktuatoren) noch nicht betreibbar sind. Das dritte Spannungsniveau kann z.B. bei 12 V liegen.
• - ein viertes Spannungsniveau, bei dem die Elektronik und die Kommunikationseinrichtung des Steuergeräts sowie alle Peripheriekomponenten betreibbar sind. Das vierte Spannungsniveau kann z.B. bei 48 V liegen.

The second voltage level can be in a range [4.5 V; 6V].

• - A third voltage level at which the electronics and the communication device of the control unit and at least one peripheral component (eg at least one sensor) can be operated, but other peripheral components (eg actuators) are not yet operable. The third voltage level can be 12 V, for example.
• - A fourth voltage level at which the electronics and the communication device of the control unit and all peripheral components can be operated. The fourth voltage level can be 48 V, for example.

The evaluation at the first voltage level has the advantage that the error-free state of the power supply path and/or the electronics can be determined in a targeted manner in the error-free state. If an error occurs, the cause can be limited to the power supply path and/or the electronics. Since the communication device is not yet activated or is not yet working, the control device cannot send or report any values for the electrical variable(s) measured at the second end of the power supply path.

The evaluation at the second voltage level has the advantage that the error-free state of the power supply path, the electronics and/or the communication device (e.g. a CAN bus interface module) can be determined in the error-free state. If an error occurs, its cause can be limited to the power supply path, the electronics and/or the communication device. Since the communication device is now activated or is working, the voltage values measured at the second end of the power supply path can be sent or reported by the control unit, so that a voltage difference between the first and the second end of the power supply path can now also be used to determine the state of health can.

The evaluation at the third voltage level has the advantage that, in the fault-free state, the fault-free state of the peripheral components that can be operated at the third voltage level, e.g. sensors, can also be assumed.

The evaluation on the third voltage level has the advantage that, in the error-free state, the error-free state of the peripheral components that can be operated on the fourth voltage level, e.g. actuators, can also be assumed.

If an error occurs, its cause can be a line fault in the power supply path (e.g. formation of an arc) or the components operated at the applied voltage level. The case can also arise in this case that the power supply path does not yet show a fault at a lower voltage level, but only at a higher voltage level.

In a further development, the group of voltage levels includes a further voltage level which is below the first voltage level and which is so low that the electronics of the control unit cannot yet be operated. As a result, a line break in the power supply path can advantageously be detected even at low voltages.

In particular, the above voltage levels can be run through successively in the specified order. The voltage applied to the power supply path is then ramped up to the normal supply voltage of the control unit, in particular in jumps. This results in the further advantage that the time required for this "smooth" run-up has a positive influence on the service life of input capacitors, for example.

It is an embodiment that on the power supply path, in particular on the first End of the power supply path, a short test voltage pulse is applied, in particular with the highest intended for the power supply path supply or operating voltage. This achieves the advantage that additional information on the presence of a fault, in particular a line fault, can be obtained quickly, in particular also before or in early phases of the gradual ramp-up according to the present method.

For example, if the associated current through the power supply path is too low compared to a reference threshold value, this can indicate line corrosion or an impending line break. On the other hand, if the associated current is too high compared to a reference threshold, this may indicate arcing. In particular, the test voltage pulse is so short that it does not activate any functional components. For example, the test voltage pulse may have a duration between 1 µs and 100 µs. A test voltage pulse can be applied in a 48 V power supply system for 1 µs and 100 µs with a level of 48 V, etc. The test voltage pulse can be output from any voltage level, and also from an otherwise voltage-free state .

The object is also achieved by a vehicle having a structural unit of an on-board power supply system of the vehicle with at least one variable DC-DC converter which is electrically connected on the output side to the first end of the power supply path, the vehicle being designed to carry out the method. The vehicle can be designed analogously to the method and vice versa, and has the same advantages.

The vehicle can be a car, truck, bus, motorcycle, etc. In particular, the vehicle can be a hybrid vehicle or an all-electric vehicle, but is not limited thereto.

In one configuration, the structural unit is coupled to an energy management system. The energy management system can be set up to run the method and can instruct the assembly or directly the variable DC-DC converter to set a specific voltage level on the output side, in particular a first to fourth voltage level as described above. In particular, the energy management system can coordinate the startup of the control unit and the power distributor and store the monitoring results in the event of a good or faulty situation.

In one configuration, the structural unit is a power distributor with a number of variable DC voltage converters, which can each be connected to different loads. The power distributor can, for example, have a DE 10 2017 210 521 A1 have the structure shown.

In one configuration, the power supply path has at least one electrical plug connection. In this case, the method can be used particularly advantageously, since plug connections are particularly susceptible to a line fault, e.g. due to corrosion, alternating mechanical stress, etc. In particular, arcs can form particularly frequently on plug connections.

In one development, the power supply path has a plug-in connection cable with plug-in connections on both sides. The plug-in connection cable can, for example, be plugged or can be plugged into an output of a power distributor on the one hand and into a control device on the other hand.

In one configuration, the power supply path has an electronic fuse at least at its first end, which is set up to measure the voltage present there and/or the electrical current flowing through the power supply path. The electronic fuse can be a component of the power distributor and can be arranged, for example, on the output side of the voltage converter.

In one development, the power supply path has an electronic fuse at its second end, which is set up to measure the voltage and/or the electrical current flowing through the power supply path. The electronic fuse can be a component of the control unit and can be arranged, for example, on a connection of the voltage converter for the plug connection cable. As an alternative or in addition, the control unit can also be set up independently without an electronic fuse to measure the voltage and/or the current at the second end of the power supply path.

In one configuration, the at least one peripheral component includes at least one sensor and/or at least one actuator, in particular at least one sensor and at least one actuator. The control unit is set up to control the at least one actuator and the at least one sensor receive sensor signals. In particular, the control device can control the at least one actuator depending on the received sensor signals.

In one configuration, the control unit and the peripheral components connected thereto form an electric braking system. In one configuration, the control unit and the peripheral components connected thereto form an electric steering system.

In one configuration, the at least one sensor can be operated at the third voltage level, e.g. at least 12 V, and the at least one actuator can be operated at the fourth voltage level, e.g. 48 V.

At least steps (a) and (c) to (f) can be carried out by basically any data processing device. The data processing device can correspond to the energy management system or be integrated into it. Alternatively, the data processing device can correspond to the power distributor or be integrated into it. It is also possible for the data processing device to be distributed over a number of components of the vehicle, in particular its on-board energy supply system, e.g. over the energy management system and the power distributor. The data processing device is set up in particular to control the DC-DC converters to output a voltage at a desired voltage level, to receive and evaluate measurement data on voltages and/or currents and/or to trigger the at least one action.

• 1 zeigt verschiedene Komponenten eines Fahrzeugs einschließlich eines Stromversorgungspfads zwischen einem variablen Gleichspannungswandler und einem Steuergerät eines Subsystems des Fahrzeugs;
• 2 zeigt als Auftragung einer Spannung gegen die Zeit einen Verlauf einer Ausgangsspannung des Gleichspannungswandlers als auch einen Verlauf einer Stromstärke durch den Stromversorgungspfad für einen fehlerfreien Zustand des Stromversorgungspfads und des Subsystems;
• 3 zeigt in einer zu 2 analogen Darstellung einen Verlauf einer Ausgangsspannung des Gleichspannungswandlers als auch einen Verlauf einer Stromstärke durch den Stromversorgungspfad bei Vorliegen eines Fehlerzustands;
• 4 zeigt in einer zu 2 analogen Darstellung einen Verlauf einer Ausgangsspannung des Gleichspannungswandlers mit einem Testpuls als auch einen Verlauf einer Stromstärke durch den Stromversorgungspfad für einen fehlerfreien Zustand des Stromversorgungspfads und des Subsystems;
• 5 zeigt in einer zu 2 analogen Darstellung einen Verlauf einer Ausgangsspannung des Gleichspannungswandlers mit einem Testpuls als auch einen Verlauf einer Stromstärke durch den Stromversorgungspfad bei einem Fehlerzustand; und
• 6 zeigt als Auftragung einer Spannung gegen die Zeit einen Verlauf einer Ausgangsspannung des Gleichspannungswandlers als auch einen Verlauf einer Spannung an dem steuergeräteseitigen Ende des Stromversorgungspfads für einen fehlerfreien Zustand des Stromversorgungspfads.

The characteristics, features and advantages of this invention described above, and the manner in which they are achieved, will become clearer and more clearly understood in connection with the following schematic description of an exemplary embodiment, which will be explained in more detail in connection with the drawings.

• 1 Figure 12 shows various components of a vehicle including a power supply path between a variable DC/DC converter and a vehicle subsystem controller;
• 2 shows, as a plot of a voltage versus time, a course of an output voltage of the DC/DC converter and a course of a current strength through the power supply path for a fault-free state of the power supply path and the subsystem;
• 3 shows in a too 2 analog representation of a course of an output voltage of the DC-DC converter and a course of a current intensity through the power supply path in the presence of a fault condition;
• 4 shows in a too 2 analog representation of a course of an output voltage of the DC-DC converter with a test pulse and a course of a current intensity through the power supply path for a fault-free state of the power supply path and the subsystem;
• 5 shows in a too 2 analog representation of a course of an output voltage of the DC-DC converter with a test pulse and a course of a current intensity through the power supply path in an error state; and
• 6 12 shows, as a voltage plotted against time, a profile of an output voltage of the DC-DC converter and also a profile of a voltage at the end of the power supply path on the control device side for a fault-free state of the power supply path.

1 shows various components of a vehicle F including a power supply path 1 between a variable DC-DC converter 2 and a control unit 3 of a subsystem 4 of the vehicle F.

The variable DC-DC converter 2 is part of a power distributor 5, which has several such variable DC-DC converters 2, all of which are connected to an input DC voltage U _G whose voltage level corresponds in particular to the nominal voltage or nominal operating voltage of an associated power supply network, e.g. a 48 V DC voltage. The variable DC-DC converter can be controlled in such a way that it either leaves the input voltage U _G present on the input side at the voltage level of the input voltage U _G or converts it to a predetermined other voltage level (in particular from a group of predetermined voltage levels), in particular converts it down.

In one variant, the variable DC voltage converter 2 is set up to measure both the DC voltage U ₁ present at its output and the current I flowing through the output. Since the output of the DC-DC converter 2 corresponds to the first end of the power supply path 1, the voltage U ₁ is the voltage present at the first end of the power supply path 1.

Optionally or additionally, the output of the voltage converter 2 can be electronically secured tion 6 be connected downstream, which is set up to measure the voltage prevailing there and the current I flowing through it. This can be useful, for example, in the event that the voltage U ₁ and/or the current I through the DC-DC converter cannot be measured or cannot be measured precisely enough. The electronic fuse 6 can be viewed as a component of the power supply path 1 . The electronic fuse 6 is arranged here directly (i.e. either directly or via a short piece of line without intermediate components) at the output of the voltage converter 2, so that the voltage measured there practically corresponds to the output voltage of the voltage converter 2, and thus also to the voltage U ₁ the first end of the power supply path 1. The voltage U ₁ and the current I can therefore in principle be measured by the voltage converter 2 and/or by the electronic fuse 6. However, it is also possible for the (desired) voltage set at the output of the DC/DC converter 2 to be used as the voltage U ₁ without also measuring it.

The power supply path 1 also includes a plug-in connection line 7, e.g. These plug-in connections 8, 9 are particularly often the cause of faults in the power supply path 1, e.g. due to their susceptibility to corrosion, weakening of the mechanical contact force due to alternating mechanical loads, etc. This can e.g. lead to an increased contact resistance or even to an arc.

In one variant, the control unit 3 can be set up to measure the voltage U ₂ applied to it on the input side, as well as the current I flowing through the input. Since the input of the control unit corresponds to the second end of the power supply path 1, the voltage is U ₂ the voltage present at the second end of the power supply path 1 . Optionally or additionally, the input of the control unit 3 can be followed by an electronic fuse (not shown), which is set up to measure the voltage prevailing there and the current I flowing through it. This can be useful, for example, in the event that the voltage U ₂ and/or the current I cannot be measured by the control device 3 or cannot be measured precisely enough. This electronic fuse can be viewed as an independent component or as a component of control unit 3 .

In general, instead of an electronic fuse, a pure measuring device or circuit that can be monitored can be used.

Control unit 3 is connected to at least one sensor 10 and to at least one actuator 11 . It can, for example, receive sensor data from the at least one sensor 10 and use it to control the at least one actuator 11.

The control unit 3 can also have electronics 12 and a communication module 13 . By means of the communication module 13, eg a CAN bus interface, the control unit 3 can communicate with the power distributor 5 and/or with an energy management system 15 via a communication connection 14, eg a CAN bus. In particular, the currently measured voltage U ₂ and possibly the currently measured current I can be reported via the communication module 13 .

For further description, it is assumed, for example, that the DC voltage U ₁ at the first end of the power supply path 1 can be set to at least two of the following voltage levels by means of the DC-DC converter 2: U _1.0 0V, no voltage. U _1.1 [2.5; 3] V. This “first” voltage level is sufficient to operate the electronics 12 of the control unit 3, but not sufficient to operate the communication module 13, the at least one sensor 10 or the at least one actuator 11. U _1.2 [5; 6] V. This “second” voltage level is sufficient to operate the electronics 12 and the communication module 13 of the control unit 3, but not sufficient to operate the at least one sensor 10 or the at least one actuator 11. U _1.3 12 V. This “third” voltage level is sufficient to also operate the at least one sensor 10, but not sufficient to also operate the at least one actuator 11. The subsystem 4 could then be operated partially functionally using its at least one sensor 10 . U _1.4 48 V. This “fourth” voltage level is sufficient to also operate the at least one actuator 11 . Consequently, the subsystem 4 can be operated with its full functionality.

2 shows a curve of the output voltage U ₁ of the DC-DC converter 2 at the first end of the power supply path 1 for a fault-free state of the power supply path 1 and the subsystem 4 as a plot of a voltage U versus time t, which is not true to scale 1 drawn without the associated y-axis.

Before the vehicle F starts driving, its consumers are to be booted up and required, e.g. subsystem 4. This is done here by gradually booting from the dead state with the voltage level U _1.0 = 0 V to the fourth voltage level U ₁ , which takes a certain amount of time _,4 = 48V

First, the voltage U ₁ is raised in one step to the first voltage level U _1,1 and held there for a “first” period. The period of time is such that the electronics 12 of the control unit 3 can start up completely. However, control unit 3 cannot yet communicate. Since it is known from manufacturer information, experiments and/or simulations how much current the electronics 12 usually consumes in its booted state, the current I measured at the first end of the power supply path 1 can be compared with the current to be expected at this first voltage level U _1,1 as be compared to the reference. If, for example, the measured current I is then within a specific reference band to be expected, it can be assumed that the electronics 12 are in a fault-free state.

Subsequently, and in particular if an error-free state has been determined beforehand, the voltage U ₁ is raised to the second voltage level U ₁ , ₂ by appropriate activation of the DC-DC converter 2 and held there for a “second” period of time. The second time period is dimensioned in such a way that the communication module 13 of the control device 3 can start up completely and possibly also until a communication connection with the power distributor 2 and/or the energy management system 15 has been established. Since it is known from manufacturer information, experiments and/or simulations how much power the electronics 12 and the communication module 13 consume in their booted state, the current I measured at the first end of the power supply path 1 can be compared to the voltage level U ₁ , ₂ at this second level expected current can be compared as the reference. If, for example, the measured current I is then within a specific reference band to be expected, it can be assumed that the communication module 13 is in a fault-free state.

Analogously, the voltage U ₁ can be raised to the third voltage level U _1.3 and then further to the fourth voltage level U _1.4 for a “third” period of time and to an error-free level by respective reference comparisons of the measured current I with an associated reference threshold value or reference band or faulty state (here a fault-free state) of the at least one sensor 10 or of the at least one actuator 11 can be closed.

3 shows in a too 2 Analog representation of a curve of the output voltage U ₁ to the second voltage level U _1.2 , wherein the measured current I for the voltage level U _1.1 is within the usual range of values for a fault-free state. If, on the other hand, a switch is made to the second voltage level U ₁ , ₂ , the measured current rises sharply after a short time and is then outside the permitted reference range for a fault-free state. This indicates an error condition, for example that an actuator is being controlled in an incorrect voltage window (here already at U ₁ , ₂ instead of U _1,4 ). Then the power supply path 1 is error-free, but not the control or function of an output stage for an actuator 11. Upon detection of the error status, an error message can be output, for example, to the energy management system 15 and/or another action can be triggered, for example further booting of the voltage U ₁ can be prevented, the control unit 3 can be switched off, etc.

4 shows in a too 2 Analog representation shows a course of the voltage U ₁ , which now includes a test pulse T, as well as a course of a current intensity through the power supply path 1 for a fault-free state of the power supply path 1 and the subsystem 4. The test pulse T is of short duration, e.g. between 1 µs and 100 µs, and can in principle be applied during any voltage level below U _1.4 , as shown here, for example, to the _second voltage level U _1.2 of approx. 6 V. In particular, the voltage level of the test pulse T corresponds to the nominal value of the associated On-board power supply system, for example 48 V. The duration of the test pulse is particularly so short that no components 10 to 13 of the control unit are put into operation if they are not already put into operation. The application of the test pulse T specifically at the second voltage level U ₁ , ₂ has the advantage that the communication capability of the control unit 3 has already been established, so that the electrical variables voltage and current present at the second end of the power supply path 1 are also measured and communicated can, which allows a particularly detailed error cause in the event of an error, e.g also a consideration of a voltage difference across the power supply path 1. In addition, no dynamic electrical effects from the sensors 10 and actuators 11 advantageously occur at the second voltage level U ₁ , ₂ .

The corresponding response of the current I is also high here and is in the range of values expected for a fault-free state.

5 shows in a too 4 analog representation of a profile of the voltage U ₁ with the test pulse T. The current intensity of the associated current I is comparatively low here and is not in the range of values expected for a fault-free state. As a result, an error condition is detected. This comparatively low current may have been generated, for example, by corrosion at a contact point, a narrowing of the line in the area of a contact point, for example by a material fracture in a plug contact, an arc, etc.

6 shows a plot of a voltage versus time a course of the voltage U ₁ at the converter-side, first end of the power supply path 1 and a course of a voltage U ₂ at the controller-side, second end of the power supply path 1 for a fault-free state of the power supply path 1. The size, which is compared here with the reference is the voltage difference ΔU = |U ₁ - U ₂ |. The voltage difference ΔU is a measure of the state of health of the power supply path 1 since, according to Ohm's law, the voltage difference increases the greater the associated ohmic resistance. A noticeable increase in the voltage difference ΔU can occur, for example, due to corrosion, loosening of a mechanical contact, etc.

By considering the voltage difference, the additional advantage is achieved that it can be reliably detected whether there is a fault in the power supply path 1 . In general, a possible fault cause can be narrowed down even more precisely in an overall perspective with the current I flowing through the power supply path 1, since the state of health of the power supply path 1 can be assessed separately by the voltage difference.

If the voltage difference .DELTA.U is evaluated for each of the set voltage levels U _1.1 to U _1.4 , it can be recognized whether an error occurs in the power supply path 1 and at which applied voltage U ₁ it occurs.

Of course, the present invention is not limited to the embodiment shown.

In general, "a", "an" etc. can be understood as a singular or a plural number, in particular in the sense of "at least one" or "one or more" etc., as long as this is not explicitly excluded, e.g. by the expression "exactly a" etc.

A numerical specification can also include exactly the specified number as well as a usual tolerance range, as long as this is not explicitly excluded.

Reference List

1

power path

2

DC converter

3

control unit

4

subsystem

5

power distributor

6

Electronic fuse

7

connector cable

8th

connector

9

connector

10

sensor

11

actuator

12

electronics

13

communication module

14

communication link

15

energy management system

f

vehicle

I

Electricity

UG

input DC voltage

U1

DC voltage present at the first end of the power supply path

U2

DC voltage present at the second end of the power supply path

U1,0

De-energized state

U1,1

First level of tension

U1,2

Second level of tension

U1,3

Third level of tension

U1,4

Fourth level of tension

T

test pulse

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102017210521 A1 [0003, 0044]
• DE 102013207775 A1 [0004]
• DE 10203921 A1 [0005]
• DE 10211970 A1 [0006]
• DE 102019125293 A1 [0007]

Claims (13)

Method for testing at least one power supply path (1) and/or at least one consumer (3, 4, 10, 11) connected to it, wherein in the method: (a) starting from a voltage-free state, a voltage (U ₁ ) is applied with a first voltage level (U _1.1 , U _1.2 , U _1.3 ), (b) at least one electrical variable (U ₁ , U ₂ , I) of the power supply path (1) is measured, ( c) the at least one measured electrical variable (U ₁ , U ₂ , I) and/or a variable derived therefrom is compared with a reference, (d) if the result of the comparison indicates an error state, at least one action is triggered, (e) at least when the result of the comparison indicates an error-free state, a voltage (U ₁ ) is applied to the power supply path (1) whose voltage level (U _1.2 , U _1.3 , U _1.4 ) is above of the previous voltage level (U _1.1 , U _1.2 , U _1.3 ), and (f) following steps (b) b is (e) to be executed again. procedure after claim 1 , in which steps (e) to (f) are carried out several times until a maximum voltage level (U _1.4 ) is reached. Method according to one of the preceding claims, in which the at least one electrical variable (U ₁ , U ₂ , I) measured in step (b) is a voltage (U ₁ ) present or set at a first end of the power supply path (1) remote from the consumer, a voltage (U ₂ ) present at a second end of the power supply path (1) connected to the consumer and/or a current (I) flowing through the power supply path (1). Method according to one of the preceding claims, in which the consumer is a control unit (3), the control unit (3) has electronics (12) and a communication device (13) and with at least one peripheral component which can be supplied with electrical energy via the control unit (3). (10, 11) is connected. procedure after claim 4 , in which the control unit (3), at least one peripheral component (10, 11) or components (12, 13) thereof at at least two different voltage levels (U _1.1 , U _1.2 , U _1.3 , U _1.4 ) are operable. procedure after claim 5 , In which the voltage levels (U _1.1 , U _1.2 , U _1.3 , U _1.4 ) comprises at least two voltage levels from the group of the following voltage levels: - a first voltage level (U _1.1 ) in which the electronics (12) of the control unit (3) can be operated, but neither the communication device (13) nor any peripheral component (10, 11); - A second voltage level (U _1.2 ) at which the electronics (12) of the control unit (3) and the communication device (13) can be operated, but no peripheral components (10, 11); - A third voltage level (U _1,3 ) at which the electronics (12) and the communication device (13) of the control unit (3) and at least one peripheral component (10) can be operated, but at least one other peripheral component (11) cannot yet is operable; - A fourth voltage level (U _1.4 ) at which the electronics (12) and the communication device (13) of the control unit (3) and all peripheral components (10, 11) can be operated. procedure after claim 5 or 6 , in which a short test voltage pulse (T) with the highest operating voltage (U _1,4 ) intended for the power supply path (1) is applied to the first end of the power supply path (1). Vehicle (F) having a structural unit of an on-board power supply system of the vehicle (F) with at least one variable DC-DC converter (2) which is electrically connected on the output side to the first end of the power supply path (1), the vehicle (F) being designed to carry out the method is. Vehicle (F) to claim 8 , wherein the structural unit is a power distributor (5) with a plurality of variable DC-DC converters (2), which can each be connected to different consumers (3, 4, 10, 11). Vehicle (F) according to one of Claims 8 until 9 , wherein the power supply path (1) has at least one electrical plug connection (8, 9). Vehicle (F) according to one of Claims 8 until 10 , wherein the power supply path (1) has at least at its first end an electronic fuse (6), which is set up to the voltage (U ₁ ) at the first end of the power supply path (1) and / or through the power supply path (1) to measure the electric current (I) flowing. Vehicle (F) according to one of Claims 8 until 11 , wherein the at least one peripheral component (10, 11) comprises at least one sensor (10) and/or at least one actuator (11). Vehicle (F) to claim 12 , wherein the at least one sensor (10) on the third voltage level (U _1.3 ) and the at least one actuator (11) on the fourth voltage level (U _1.4 ) can be operated.

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