Onboard power supply device for supplying electrical loads in a motor vehicle, as well as motor vehicle, switching device and method for operating an onboard power supply device

Abstract

The invention relates to an electric onboard power supply device (11) for supplying at least two electrical loads (21, 22) with an onboard power supply voltage (U) in a motor vehicle (10), wherein the onboard power supply device (11) comprises: a connection device (18) for receiving the onboard power supply voltage (U) from a voltage source (12); and a first onboard power supply branch (14) for connecting one or some of the loads (21) and for supplying the onboard power supply voltage (U) to each connected load (21). The present invention is provided in such a way that a second onboard power supply branch (15) is provided for connecting each of the remaining loads (22) and for supplying the onboard power supply voltage (U) to each of the remaining loads (22), and a connecting device (18) is connected to both the first onboard power supply branch (14) and the second onboard power supply branch (15) via at least one switching element (26), and a control device (27) is configured to electrically couple the connecting device (18) alternately to the first and second onboard power supply branches (15) by switching at least one switching element (26).

Description

Technical Field

[0001] The invention relates to an onboard power supply device for supplying power to at least two electrical loads in a motor vehicle. The loads can be supplied with an electrical onboard power supply voltage from a voltage source via the onboard power supply device. The invention also includes a motor vehicle with an onboard power supply device and a switching device, which is an important component of the onboard power supply device. Finally, the invention also includes a method for operating the onboard power supply device. Background Art

[0002] With the aid of the onboard power supply arrangement, a so-called onboard power supply, i.e. an electrical distribution device, can be provided in a motor vehicle in order to transmit an onboard power supply voltage from a voltage source to at least two electrical loads. In a motor vehicle, for example, a 12-volt onboard power supply can be provided, in which the onboard power supply voltage then has a nominal value of 12 volts. Other known types of onboard power supplies are 48-volt onboard power supplies and high-voltage onboard power supplies, wherein in the latter a power supply voltage of more than 60 volts, in particular more than 100 volts, can be provided.

[0003] That is, the voltage source and the electrical load are electrically coupled to each other through the onboard power supply device. However, if a fault, such as a short circuit, occurs in one of the electrical loads, the voltage source and any other loads are also implicated. This is particularly undesirable for electrical loads that are critical to the driving ability of the motor vehicle. If such a load becomes inoperable due to a fault in the onboard power supply device, the entire motor vehicle will not be able to drive. In this context, it is known to provide redundant power supplies for certain electrical loads in a motor vehicle. However, this involves higher component costs, especially when two voltage sources are to be provided.

[0004] With regard to the detection of faults in an onboard power supply system, a testing method is known from DE 10 2010 014 070 A1, which can be carried out in a hybrid vehicle using a battery model.

[0005] With regard to checking the disconnection paths for the energy supply, a test for such disconnection paths is known from DE 10 2012 209 144 A1, with which a reliable disconnection of the voltage source in the motor vehicle can be ensured.

[0006] WO 2015 / 071045 A1 discloses coupling a power source to an electrical load in a motor vehicle via a modulator for power modulation and a demultiplexer for switching between the loads, so that only one modulator is required for a plurality of loads. It is provided that only one of the loads is currently operated. If a plurality of loads are operated simultaneously, a plurality of modulators and / or demultiplexers are provided accordingly (one for each load to be operated simultaneously).

[0007] US2011 / 0273012 A1 discloses that in an electric aircraft, a generator for generating electricity is connected to an electric inverter via an electric power bus, and then the inverter is further selectively connected to different loads by means of an electric router. The router is used to supply power to loads that currently require energy, while the remaining loads remain unpowered.

[0008] It is known from DE 10 2015 012 944 A1 that an electrical load can always be switched to another supply branch in the event of a fault in its standard supply branch.

[0009] DE 10348162 B3 discloses connecting safety-related loads in a motor vehicle to a voltage source via two different branches, so that in the event of a failure of one of the branches or one of the voltage sources, power can be supplied directly via the remaining branch. In each of the branches, an energy storage device can also be permanently provided. Summary of the invention

[0010] The object of the present invention is to limit the effects of a fault in an onboard power supply system in a motor vehicle in such a way that not all electrical loads are affected by the fault in terms of their mode of operation.

[0011] This object is achieved by the present invention. Advantageous embodiments of the present invention are described in the following description and the accompanying drawings.

[0012] The invention provides an electric vehicle power supply device, with which at least two electrical loads in a motor vehicle can be supplied with a vehicle power supply voltage. The vehicle power supply device has a connection device for receiving the vehicle power supply voltage from a voltage source. That is, the vehicle power supply voltage can be electrically connected to the voltage source by means of the connection device. The vehicle power supply voltage is in particular a DC voltage. The vehicle power supply voltage can have a rated value of 12 volts, for example.

[0013] The onboard power supply branch of the onboard power supply device is designed to connect one or more of the loads and to transmit the onboard power supply voltage to each of the connected loads. The onboard power supply branch can be realized based on at least one cable and / or at least one bus bar, for example. Not all loads are connected to the onboard power supply branch, but only one or more of the loads. The onboard power supply branch is referred to as the first onboard power supply branch below.

[0014] In order to reduce the influence of an electrical fault in the onboard power supply device, a second onboard power supply branch is provided in the onboard power supply device, to which each of the remaining loads can be connected. The second onboard power supply branch is designed to deliver the onboard power supply voltage to each of the remaining loads, that is, to each load connected to the second onboard power supply branch. The second onboard power supply branch can also be realized in the manner described based on at least one cable and / or at least one busbar. Thus, there is one connection device and two onboard power supply branches in the onboard power supply device.

[0015] In the on-board power supply device, the connection device is now connected to the first on-board power supply branch and to the second on-board power supply branch via a switching element or multiple switching elements of the switching device. The switching device is thus connected between the connection device on the one hand and the two on-board power supply branches on the other hand. With the help of the switching device, it is possible to switch between the two on-board power supply branches in the manner of controlling at least one switching element or changing its switching state. As a result, the connection device (and thus the voltage source) is electrically coupled to the first on-board power supply branch in the first switching position of at least one switching element, and electrically coupled to the second on-board power supply branch in the second switching position of at least one switching element. On the contrary, the corresponding other on-board power supply branch is electrically decoupled from the connection device (and thus the voltage source) during this period. The control device of the switching device in the on-board power supply device is designed to electrically couple the connection device alternately with the first on-board power supply branch and the second on-board power supply branch by switching at least one switching element. During the electrical coupling of one of the on-board power supply branches with the connection device, the corresponding other on-board power supply branch is electrically decoupled from the connection device in the described manner. The onboard power supply voltage from the voltage source is therefore transmitted or fed at any point in time only into one of the two onboard power supply branches.

[0016] The invention provides the following advantages: In the event that an electrical load generates an electrical fault in the onboard power supply system, the fault only affects the onboard power supply branch to which the defective electrical load is connected. Due to the described electrical wiring, the two onboard power supply branches are not electrically coupled to each other at any time. As a result, an electrical fault in one onboard power supply branch will never affect the electrical loads or the electrical load of the other onboard power supply branch. This ensures that not all electrical loads connected to the onboard power supply system are affected by the electrical fault.

[0017] The invention provides that a corresponding electrical buffer is connected to each onboard power supply branch, which provides electrical energy to each corresponding connected load during operation of the motor vehicle, while at least one switching element connects the connection device to another onboard power supply branch. For example, an electrical storage battery, such as a lithium-ion battery and / or a lead-acid battery, and / or a component with at least one capacitor can be provided as a buffer. The buffer in each onboard power supply branch has the advantage that each electrical load connected to the onboard power supply branch can be continuously supplied with electrical energy. Each time the at least one switching element is switched to the onboard power supply branch, the buffer can be recharged.

[0018] The invention also includes embodiments that yield additional advantages.

[0019] In one embodiment, the switching device also includes a checking device, which is set up for the following situation: at least one switching element connects the connection device to one of the onboard power supply branches (i.e., is switched to one of the onboard power supply branches), during which a predetermined normal standard is checked in the other onboard power supply branch. The normal standard can, for example, describe an electrical condition indicating that the onboard power supply branch is not short-circuited or fault-free. The control device is set up to switch at least one switching element to the other onboard power supply branch only if the checking device sends a signal that the normal standard is met in the other onboard power supply branch. In other words, if a violation of the normal standard is detected in the other onboard power supply branch before switching, i.e., for example, a short circuit or an arc exists, then in this case, the following situation can be prevented: at least one switching element is switched to the other onboard power supply branch and thus, that is, the fault of the other onboard power supply branch also reacts to the voltage source. The checking device can be designed in a manner already known to detect electrical faults in the corresponding onboard power supply branch.

[0020] If, on the other hand, an electrical fault occurs in the onboard power supply branch to which at least one switching element is currently switched, one embodiment provides that, in the event that the checking device signals a violation of the normal standard in the onboard power supply branch to which at least one switching element is currently switched, i.e. the voltage source is just electrically coupled to said onboard power supply branch, at least one switching element is switched to another onboard power supply branch, which is triggered by the control device. That is, the onboard power supply branch in which the normal standard is violated is switched away. This disconnects the onboard power supply branch from the voltage source and reduces the effects of the electrical fault, for example by reducing the current flowing through the onboard power supply branch.

[0021] One embodiment is provided such that the normal criterion includes that in the corresponding onboard power supply branch where the normal criterion is checked by the checking device, the current intensity is less than a predetermined maximum value and / or is continuously less than the maximum value since the last switching of at least one switching element. That is, the check is performed at a time point or over a period of time. By monitoring the current intensity, a short circuit and / or an arc can be identified. In addition to this or as an alternative to this, the normal criterion can include that the branch voltage in the onboard power supply branch (i.e. the voltage of the onboard power supply branch) is greater than a predetermined minimum value and / or is continuously greater than a predetermined minimum value since the last switching of at least one switching element. Here, the branch voltage is also detected at a time point or a period of time is observed. By monitoring this period of time, there is the following advantage: faults that occur briefly are also identified and have an influence on the decision about the switching of at least one switching element. In addition to this or as an alternative to this, the normal criterion can include that each connected load must send a signal of a fault-free operating state. Thus, the self-diagnosis of each electrical load is advantageously utilized by the checking device.

[0022] One embodiment provides that the control device is configured to generate an emergency signal if normal standards are violated, that is, by means of the emergency signal an adaptation of the operating mode to the detected electrical fault can be triggered in the motor vehicle.

[0023] One embodiment is provided that the control device of the switching device is set to always switch at least one switching element if the remaining amount of energy in the buffer of the onboard power supply branch to be switched is less than a predetermined minimum amount. That is, the frequency or speed of switching depends on the corresponding storage state or the remaining amount in the buffer of the onboard power supply branch that has just been decoupled from the voltage source. Thus, in an advantageous manner, the switching rate is adapted to the power demand of the loads in the two onboard power supply branches. This reduces the switching frequency and can thus help reduce losses. The remaining amount in the buffer can be measured using known switching technology measures and / or, for example, by means of the branch voltage generated by the buffer in the onboard power supply branch. If the branch voltage drops below a threshold, this can be used as a trigger for switching. In addition to this or in lieu of this, it can be provided that switching is performed at a predetermined switching frequency or switching rate (which can be in the range of 10 Hz to once per minute). The combination with the threshold is provided here to be independent of the threshold, that is, to switch at the switching rate in any case. Conversely, if the branch voltage has fallen below the threshold before the end of the switching period (the inverse value of the switching rate), switching occurs before the end of the switching period.

[0024] One embodiment provides that the switching device is designed according to the standard ASIL (Automotive Safety Integrity Level), in particular ASIL-C and / or ASIL-D. For this purpose, in the case of a violation of normal standards in another onboard power supply branch to be switched to, that is, when there is a fault in the onboard power supply branch, it is only necessary to ensure that the ASIL is "Nicht-Schalten, i.e., no switching". This is particularly easy to implement technically and still enables the onboard power supply device to obtain ASIL approval.

[0025] One embodiment is provided in which an additional onboard power supply branch is also provided, but it is electrically connected to a connection position arranged between a connection device and a switching device via a fuse element. It is thus a bypass which is electrically connected before the switching device, that is, connected at the connection position, from the voltage source or from its connection device. At this additional onboard power supply branch, all any electrical loads can be connected, or such electrical loads that do not require insurance implemented by two onboard power supply branches can be connected. The electrical load can be a so-called QM-load, as defined in the ASIL-standard. The additional onboard power supply branch is electrically connected to the connection position via a fuse element, which is set to interrupt such electrical connection to the connection position if the current flowing into the additional onboard power supply branch is greater than a triggering threshold. The fuse element can be designed, for example, as a fuse, or as an electrical switch with current intensity monitoring. A short circuit in the additional onboard power supply branch thus causes the additional onboard power supply branch to be electrically decoupled from the voltage source through the fuse element. As a result, an electrical fault in the additional onboard power supply branch also has no effect on electrical loads connected to the first and second onboard power supply branches on the other side of the switching device.

[0026] One embodiment provides that the control device of the switching device is set up to maintain the new switching state of at least one switching element for a predetermined minimum time after the switching of the at least one switching element. This reduces the number of switching cycles and / or recharging cycles, for example, for a buffer of an onboard power supply branch. This advantageously reduces the losses thereof.

[0027] In one embodiment, the load connected to the first onboard power supply branch is a first partial control unit of a vehicle function, such as vehicle steering, and the remaining load connected to the second onboard power supply branch is a second partial control unit of the same vehicle function, such as vehicle steering. The vehicle function is designed in this case so that it can continue to operate with only one of the two partial controls even in an emergency operation, which can be triggered by the emergency signal. This results in the following advantage: in the event of an electrical fault in one of the onboard power supply branches, the vehicle function can continue to operate continuously by continuing to supply the other onboard power supply branch with the onboard power supply voltage. As a result, even if there is an electrical fault in the onboard power supply device, for example, so-called safety-related vehicle functions such as vehicle steering and / or brake control and / or environmental monitoring can continue to operate reliably.

[0028] One embodiment provides that the voltage source is provided by a generator and / or by another onboard power supply device connected via a DC voltage converter. As a generator, for example, a belt starter generator or a so-called lighting generator (12-volt generator) can be provided. In addition or as an alternative to this, another onboard power supply device, for example a high-voltage onboard power supply or a 48-volt onboard power supply, can be connected via a DC voltage converter. Thus, in an advantageous manner, the generator voltage generator (i.e., the voltage source) can be disconnected from the first and second onboard power supply branches by means of a switching device. In each onboard power supply branch, as a further voltage generator, preferably only a buffer is provided, i.e., an energy storage device that is self-depleted in the event of a short circuit, but not a generator voltage generator. Thus, in the event of a short circuit in the onboard power supply branch, the electrical energy converted therein is limited.

[0029] According to one aspect, the invention also includes a motor vehicle, which is characterized in that it has an embodiment of the onboard power supply arrangement according to the invention. In the motor vehicle, a plurality of loads can be distributed between two onboard power supply branches, so that in the event of an electrical fault, not all loads connected to the onboard power supply branches are affected by the electrical fault, but only those loads connected to the onboard power supply branch in which the electrical fault occurred. Furthermore, a reactionary effect of the electrical fault on the voltage source can be avoided.

[0030] In the context of the present invention, a motor vehicle is preferably an automobile, in particular a passenger car or a truck.

[0031] In order to provide the type of on-board power grid device in a motor vehicle, a switching device is provided for the on-board power grid device. The switching device according to the present invention has at least one switching element and a control device. Each switching element can be formed based on a semiconductor switch, especially a transistor, for example, or based on a circuit composed of a plurality of such semiconductors connected in parallel. The control device can be implemented, for example, based on at least one microcontroller. At least one switching element is configured to connect the connection device of the on-board power grid device to the first on-board power grid branch and the second on-board power grid branch via at least one switching element. The connection device can be implemented, for example, based on a cable and / or a busbar. In addition to this or in lieu thereof, the connection device can be implemented based on an electrical contact element such as a plug or a socket or a screw. Each on-board power grid branch can be designed in the manner described. The control device of the switching device is configured to electrically couple the connection device alternately with the first on-board power grid branch and the second on-board power grid branch by switching at least one switching element. Thus, only one of the on-board power grid branches is always connected to the connection device, while the other on-board power grid branch is electrically decoupled from the connection device. By means of the electrical coupling, a DC connection is provided between the connection device and the corresponding onboard power supply branch. By means of the decoupling, a current flow between the connection device and the corresponding onboard power supply branch is prevented.

[0032] According to one aspect, the present invention finally also includes a method for operating an embodiment of an onboard power supply device according to the present invention. The connecting device of the onboard power supply device receives the onboard power supply voltage from a voltage source. The onboard power supply voltage is in particular a DC voltage. The onboard power supply voltage can be in the range of 9 volts to 60 volts, just to give an example. One or some of at least two loads are connected at the first onboard power supply branch. Each of the remaining loads in the loads is connected at the second onboard power supply branch. That is, these loads are distributed to the two onboard power supply branches. The connecting device is connected to both the first onboard power supply branch and the second onboard power supply branch via at least one switching element of the switching device. The control device of the switching device causes the connecting device to be alternately coupled to the first onboard power supply branch and the second onboard power supply branch by switching at least one switching element. The onboard power supply voltage is thus alternately delivered to each connected load of the first onboard power supply branch and the second onboard power supply branch.

[0033] The invention also includes improvements of the method according to the invention, which have the features already described in conjunction with the improvements of the motor vehicle according to the invention. For this reason, the corresponding improvements of the method according to the invention are not described again here.

[0034] The present invention also includes combinations of features of the described embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Embodiments of the present invention are described below.

[0036] The single FIGURE shows a schematic representation of an embodiment of a motor vehicle according to the invention, in which an embodiment of the method according to the invention can be carried out. DETAILED DESCRIPTION

[0037] The embodiment described below is a preferred embodiment of the present invention. In this embodiment, the components of this embodiment are correspondingly the individual features of the present invention to be observed independently of one another, which also improve the present invention independently of one another and can therefore also be considered as components of the present invention individually or in a different combination than shown. In addition, the embodiment can also be supplemented by other features of the already described features of the present invention.

[0038] The figure shows a motor vehicle 10, which can be a car, in particular a passenger car or a truck. An onboard power supply device 11 is shown in the motor vehicle 10, which can realize the onboard power supply of the motor vehicle 10. The onboard power supply device 11 can be, for example, an onboard power supply for a DC voltage less than 60 volts (for example, with a rated value of 12 volts). A voltage source 12 can provide an onboard power supply voltage U for the onboard power supply device 11. The voltage source 12 can, for example, include a generator and / or a DC voltage converter. The onboard power supply voltage U can be generated relative to a reference potential 13 (for example, a ground potential or a vehicle ground). The onboard power supply device 11 also shows a first onboard power supply branch 14 and a second onboard power supply branch 15 and another onboard power supply branch 17. The onboard power supply branches 14 and 15 can be connected to a connection device 18 via a switching device 16, and the connection device can be connected to the voltage source 12 for receiving the onboard power supply voltage U.

[0039] The further onboard power supply branch 17 can be connected directly to the connection point 20 of the connection device 18 via a fuse element 19 (e.g. a fuse), wherein “directly” means still before the switching device 16 or, in other words, between the voltage source 12 and the switching device 16. The further onboard power supply branch 17 is thus independent of the switching process in the switching device 16.

[0040] Electrical loads 21, 22 can be connected to the onboard power supply branches 14, 15. This group of loads 21, 22 can be, for example, loads that are critical for the driving operation of the motor vehicle 10, such as vehicle steering and / or brake control and / or environmental monitoring. At least one other load 23 can be connected to the other onboard power supply branch 17, which can include, for example, an infotainment system (Information-Unterhaltungssystem), seat heating, ventilation fans and / or interior lighting, i.e., loads that are not critical for driving operation.

[0041] An electrical buffer 24 can be provided in each of the onboard power supply branches 14, 15 connected to the voltage source 12 via the switching device 16, which can include, for example, an electrical storage battery (for example, a lithium-ion battery) and / or at least one capacitor. The switching device 16 can be electrically connected to the respective onboard power supply branch 14, 15 at the respective electrical terminal 25.

[0042] The switching device 16 can have at least one switching element 26, which can be, for example, a semiconductor switch such as a transistor, or a semiconductor circuit with more than one semiconductor switch. The control device 27 of the switching device 16 can switch the at least one switching element 26. In the first switching state 28, the connection device 18 and thus the voltage source 12 are electrically coupled to the first onboard power supply branch 14, so that the onboard power supply voltage U is transmitted to the first onboard power supply branch 14. The second onboard power supply branch 15 is decoupled from the onboard power supply voltage U. In contrast, in the second switching state 29, the connection device 18 and thus the voltage source 12 are electrically coupled to the second onboard power supply branch 15, so that the onboard power supply voltage U is guided to the second onboard power supply branch 15. The first onboard power supply branch 14 is decoupled from the onboard power supply voltage U during this period. The loads 21 and 22 of the two onboard power supply branches 14 and 15 can still be continuously powered. This is ensured in the decoupled state of the respective onboard power supply branch 14 , 15 by means of the buffer 24 of the respective onboard power supply branch 14 , 15 .

[0043] The switching device 16 may include a checking device 30, which is configured to check a predetermined normality criterion 31 in the other onboard power supply branch 15, that is, to check whether a predetermined fault-free state exists in the other onboard power supply branch to be switched to, while the at least one switching element 26 is coupling the coupling device 18 to one of the onboard power supply branches 14. The control device 27 may be configured to switch the at least one switching element 26 to the other onboard power supply branch 15 only if the checking device 30 signals that the normality criterion 31 is met in the other onboard power supply branch 15.

[0044] If checking device 30 signals a violation of normal standard 31 on one of onboard power supply branches 14 , 15 and at the same time at least one switching element 26 is switched to this onboard power supply branch 14 , 15 , control device 27 can switch at least one switching element to the other onboard power supply branch 14 , 15 .

[0045] This means that if a fault state is present, in particular a short circuit and / or an arc, there is no switching to the onboard power supply branch that violates normal standard 31. This means that if an electrical fault occurs in one of onboard power supply branches 14, 15, this onboard power supply branch remains permanently electrically decoupled from voltage source 12.

[0046] Here, the loads 21, 22 preferably provide the same vehicle function for the partial control, so that two partial control are always provided for one vehicle function, and each of the partial control is connected to another onboard power supply branch 14, 15. The failure of one onboard power supply branch 14, 15 thus enables the vehicle function to continue to be operated at least in the emergency mode using the remaining partial control. Accordingly, it can be provided that, in the event of a violation of the normal standard 31, the control device 27 outputs an emergency signal 32, which, for example, sends a signal to the vehicle function to switch to the emergency mode or the emergency mode.

[0047] The onboard power supply device 11 can therefore also provide such vehicle functions which require an energy supply of ASIL (in particular ASIL-C and / or ASIL-D).

[0048] Before the onboard power supply voltage U is replaced or switched to another onboard power supply branch 14 , 15 , it can be checked at this time in this case whether an electrical fault is present at the corresponding terminal 25 .

[0049] If this is the case, ie the normal criteria 31 are violated, no switching or replacement is performed. Alternatively, an emergency signal 32 may be generated.

[0050] If the storage capacity of the corresponding buffer 24 of the onboard power supply branch 14, 15 currently decoupled from the voltage source 12 is exhausted, a switchover can always be performed. A minimum switchover time or a minimum duration 33 can be set. The minimum duration 33 can be in the range of 0.1 seconds to 2 seconds. As a result, the charging and discharging cycles of the buffer 24 can be carried out or regulated in a predictable manner. By having the buffers 24 each include at least one battery, load peaks can also be compensated.

[0051] In the onboard power supply device 11, it is physically ensured that the two terminals 25 are reliably powered. The requirement for the switching device 16 here only involves not switching in the event of a fault (violation of the normal standard 31), which makes it technically simpler to meet the ASIL. Therefore, as long as there is no electrical fault in the remaining loads 23 and the voltage source 12 can also work normally, the motor vehicle 10 can continue to drive even if there is a fault in one of the onboard power supply branches 14, 15. If there is an electrical fault in one of the remaining loads or in the remaining loads 23, it is only necessary to wait until the fuse element 19 is triggered, and thereby the other onboard power supply branch 17 is disconnected or electrically decoupled from the voltage source 12. The onboard power supply device 11 is then safe again. Even in the case of such a redundant design using two onboard power supply branches 14, 15, the buffer 24 only needs to meet smaller ASIL requirements.

[0052] Overall, this example shows how a 12-volt energy grid can be stored for autonomous driving functions using the present invention.

[0053] Reference numerals list:

[0054] 10 Motor Vehicles

[0055] 11 On-board power grid device

[0056] 12 Voltage Source

[0057] 13 Reference potential

[0058] 14 First onboard power grid branch

[0059] 15 Second onboard power supply branch

[0060] 16 Switching device

[0061] 17 Another onboard power supply branch

[0062] 18 Connecting equipment

[0063] 19 Safety element

[0064] 20 Connection parts

[0065] 21 Electrical load

[0066] 22 Electrical load

[0067] 23 Electrical load

[0068] 24 Electrical Buffer

[0069] 25 Terminal

[0070] 26 Switching elements

[0071] 27 Control Equipment

[0072] 28 Switching state

[0073] 29 Switch state

[0074] 30 Check Equipment

[0075] 31 Normal Standard

[0076] 32 Emergency Signal

[0077] 33 Minimum duration

[0078] U Onboard electrical system voltage.

Claims

1. An electrical onboard power supply device (11) for supplying at least two electrical loads (21, 22) with an onboard power supply voltage (U) in a motor vehicle (10), wherein: The vehicle-mounted power grid device (11) comprises: - a connection device (18) for receiving the onboard power supply voltage (U) from a voltage source (12); and a first onboard power supply network branch (14) for connecting one or some of the loads and for delivering the onboard power supply network voltage (U) to each connected load, A second on-board power grid branch (15) is provided for connecting each of the remaining loads and for transmitting the on-board power grid voltage (U) to each of the remaining connected loads, and The coupling device (18) is connected both to the first onboard power supply branch (14) and to the second onboard power supply branch (15) via at least one switching element (26) of the switching device (16), The control device (27) of the switching device (16) is configured to electrically couple the coupling device (18) alternately to the first onboard power supply branch (14) and the second onboard power supply branch (15) by switching the at least one switching element (26). It is characterized in that During the electrical coupling of one of the onboard power supply branches (14, 15) to the connection device (18), the respective other onboard power supply branch (15, 14) is electrically decoupled from the connection device (18) and the onboard power supply voltage (U) from the voltage source (12) is transmitted to only one of the two onboard power supply branches (14, 15) at any time and the two onboard power supply branches (14, 15) are not electrically coupled to one another at any time, A corresponding electrical buffer (24) is connected to each onboard power supply branch (14, 15), and the buffer provides electrical energy to each corresponding connected load (21, 22), and the at least one switching element (26) connects the connection device (18) to the corresponding other onboard power supply branch (14, 15), and through the corresponding buffer (24) in each onboard power supply branch (14, 15), each electrical load (21, 22) connected to the corresponding onboard power supply branch (14, 15) is continuously supplied with electrical energy. And each time the at least one switching element (26) is switched to the corresponding onboard power supply branch (14, 15), the corresponding buffer can be recharged.

2. The vehicle power system device (11) according to claim 1, wherein: The switching device (16) comprises a checking device (30) which is configured to check a predetermined normality criterion (31) in one of the onboard power supply branches while the at least one switching element (26) is connecting the coupling device (18) to the other onboard power supply branch, and the control device (27) is configured to switch the at least one switching element (26) to the other onboard power supply branch only if the checking device (30) sends a signal that the normality criterion (31) is met in the other onboard power supply branch.

3. The vehicle power system device (11) according to claim 2, wherein: In the event that the checking device (30) signals that the normal standard (31) is violated in one of the onboard power supply branches (14, 15) and the at least one switching element (26) is switched to the onboard power supply branch (14, 15), the control device (27) is configured to switch the at least one switching element to the other onboard power supply branch (14, 15).

4. The vehicle power grid device (11) according to claim 2, wherein: The normal standard (31) comprises, in the corresponding onboard power supply branch (14, 15), - the current intensity is less than a predetermined maximum value and / or has been continuously less than this maximum value since the last switching of the at least one switching element (26); and / or, - the branch voltage is greater than a predetermined minimum value and / or has been continuously greater than this minimum value since the last switching of the at least one switching element (26); and / or, - Each connected load (21, 22) signals a fault-free operating state.

5. The vehicle power grid device (11) according to any one of claims 2 to 4, wherein: The control device (27) is configured to generate an emergency signal (32) if the normal standard (31) is violated.

6. The vehicle power grid device (11) according to any one of claims 1 to 4, wherein: The control device (27) is configured to switch the at least one switching element (26) if the remaining amount in the buffer (24) of the onboard power supply branch (14, 15) to which the switch is to be made is less than a predetermined minimum amount, and / or the switching is performed at least at a predetermined switching rate.

7. The vehicle power grid device (11) according to any one of claims 1 to 4, wherein: The additional onboard power supply branch (17) is electrically connected to a connection point (20) arranged between the connection device (18) and the switching device (16) via a fuse element (19), wherein the fuse element (19) is configured to interrupt the electrical connection between the additional onboard power supply branch (17) and the connection point (20) if a current flowing into the additional onboard power supply branch (17) is greater than a triggering threshold.

8. The vehicle power grid device (11) according to any one of claims 1 to 4, wherein: The control device (27) is designed to maintain the new switching state of the at least one switching element (26) for a predetermined minimum time period (33) after the at least one switching element (26) has been switched.

9. The vehicle power grid device (11) according to any one of claims 1 to 4, wherein: The load connected to the first onboard power supply branch (14) is a first partial control unit of a vehicle function, and the remaining load connected to the second onboard power supply branch (15) is a second partial control unit of the same vehicle function.

10. The vehicle power grid device (11) according to any one of claims 1 to 4, wherein: The voltage source (12) is provided by a generator and / or by a further onboard power supply device (11) connected via a DC voltage converter.

11. A motor vehicle (10), characterized in that The motor vehicle (10) has an onboard power supply device (11) according to any one of claims 1 to 10.

12. Method for operating an onboard power supply system (11) according to any one of claims 1 to 10, wherein: The connecting device (18) of the onboard power supply arrangement (11) receives the onboard power supply voltage (U) from the voltage source (12), and one or some of the at least two loads (21, 22) are connected to the first onboard power supply branch (14). wherein each of the remaining loads is connected to a second onboard power supply branch (15), the connecting device (18) is connected to both the first onboard power supply branch (14) and the second onboard power supply branch (15) via at least one switching element (26) of a switching device (16), a control device (27) of the switching device (16) causes the connecting device (18) to be alternately electrically coupled to the first onboard power supply branch (14) and the second onboard power supply branch (15) by switching the at least one switching element (26), and thereby the onboard power supply voltage (U) is alternately supplied to each connected load of the first onboard power supply branch (14) and each connected load of the second onboard power supply branch (15), It is characterized in that During the electrical coupling of one of the onboard power supply branches (14, 15) to the connection device (18), the respective other onboard power supply branch (15, 14) is electrically decoupled from the connection device (18) and the onboard power supply voltage (U) from the voltage source (12) is transmitted to only one of the two onboard power supply branches (14, 15) at any time and the two onboard power supply branches (14, 15) are not electrically coupled to one another at any time, A corresponding electrical buffer (24) is connected to each onboard power supply branch (14, 15), and the buffer provides electrical energy to each corresponding connected load (21, 22), and the at least one switching element (26) connects the connection device (18) to the corresponding other onboard power supply branch (14, 15), and through the corresponding buffer (24) in each onboard power supply branch (14, 15), each electrical load (21, 22) connected to the corresponding onboard power supply branch (14, 15) is continuously supplied with electrical energy. Each time the at least one switching element (26) is switched to the corresponding onboard power supply branch (14, 15), the corresponding buffer is recharged.

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