Vehicle electrical system and power module for such a vehicle electrical system

Abstract

Describes a vehicle electrical system (4) configured for use in a vehicle (2), the vehicle electrical system having a first sub-network (6) and a second sub-network (8), at least one energy source (10, 12, 14) being connected to the first sub-network and the second sub-network respectively, wherein the first sub-network (6) has a different voltage level from the second sub-network (8), the vehicle electrical system having at least one safety-related energy consumer (16) connected to one of the sub-networks (6, 8), wherein the sub-network (6, 8) has two partial networks (18, 20, 22, 24) and the energy consumer (16) is connected to the two partial networks (18, 20, 22, 24), so that the energy consumer (16) is connected to the energy sources (10, 12, 14) of the sub-network (6, 8) via two independent supply lines (V1, V2), the vehicle electrical system further having a power module (28) that connects the two sub-networks (6, 8) to each other and is configured in such a way that each of the two supply lines (V1, V2) can be connected to the two energy sources (10, 12, 14), so that the energy consumer (16) can be supplied by the two energy sources (10, 12, 14) via the two supply lines (V1, V2) respectively. A corresponding power module (28) is also described.

Description

Field of the Invention

[0001] The present invention relates to a vehicle electrical system and a power module for such a vehicle electrical system. Background Art

[0002] Vehicle electrical systems are generally used to distribute energy within a vehicle. To this end, vehicle electrical systems often have multiple supply lines in order to connect distributed consumers to one or more energy sources for the supply of electrical energy. The consumers and energy sources are accordingly connected to the vehicle electrical system. Some vehicle electrical systems have multiple subnets with different voltage levels in order to be able to optimally operate consumers with different electrical requirements separately. The subnets are electrically connected to each other so that energy can be exchanged between these subnets if necessary.

[0003] Power modules are used to distribute energy within a vehicle electrical system.

[0004] DE 101 50 379A1 describes an energy supply system for safety-relevant consumers. This energy supply system is supplied with energy via two independent supply lines respectively.

[0005] DE 10 2014 214 103 A1 describes a vehicle electrical system topology that has two redundant consumers in each of two safety-relevant partial networks. One of the partial networks is connected to a low-voltage vehicle electrical system, while the other partial network is connected to a high-voltage vehicle electrical system. The two vehicle electrical systems are connected via a DC / DC converter. The redundant consumers can be supplied by the two vehicle electrical systems independently of each other.

[0006] DE 100 53 584A1 describes a redundant voltage supply device for safety-relevant consumers in a motor vehicle. A DC / DC converter can be dispensed with by a special distribution. Summary of the Invention

[0007] In this context, the object of the present invention is to provide an improved vehicle electrical system that ensures the highest possible safety in supplying safety-relevant consumers. In addition, an improved power module for such a vehicle electrical system should be provided.

[0008] According to the present invention, this object is solved by a vehicle electrical system having features according to the present invention and by a power module having features according to the present invention. Here, the embodiments related to the vehicle electrical system also apply to the power module in terms of meaning and vice versa.

[0009] The vehicle electrical system is configured for use in a vehicle. The vehicle is in particular a motor vehicle, such as a passenger vehicle or a goods vehicle. The vehicle is in particular driven electrically or by an internal combustion engine or by both together.

[0010] The vehicle electrical system has a first sub-network and a second sub-network, and at least one energy source is connected to the first sub-network and the second sub-network respectively, wherein the voltage level of the first sub-network is different from the voltage level of the second sub-network. Therefore, at least one first energy source is connected to the first sub-network, and at least one second energy source is connected to the second sub-network. The energy sources of the respective sub-networks define the voltage levels of the respective sub-networks. The voltage levels of the respective sub-networks indicate how much voltage can be provided in the sub-network for supplying the consumers. Therefore, corresponding to the different voltage levels of the two sub-networks, the two energy sources have different voltages. Preferably, the voltage level of the first sub-network is less than the voltage level of the second sub-network.

[0011] The vehicle electrical system has at least one safety-related consumer, which is connected to one of the sub-networks, wherein the sub-network has two partial networks and the consumer is connected to the two partial networks, so that the consumer is connected to the energy source of the sub-network via two independent supply lines. This is different from DE 101 50 379 A1 mentioned at the beginning, wherein a component is not connected to the same energy source of the corresponding sub-network via two independent supply lines. Unless otherwise specifically stated, "consumer" is understood hereinafter as a safety-related consumer. Here, the consumer is directly connected especially only to one of the sub-networks, that is, not directly connected to the other sub-network. The energy source is especially only connected to one of the partial networks, however, the two partial networks are connected to each other so that the two partial networks are supplied by the energy source. Therefore, the sub-network is divided into two partial networks, and each partial network includes one of the supply lines, so that the consumer can be supplied with energy via different partial networks, that is, the consumer is connected to the energy source redundantly. In the case of the failure of one of the supply lines or one of the partial networks, the energy supply is still carried out via the other partial network using the other supply line. In contrast, one or more optionally existing comfort consumers are preferably each only connected to a single partial network and are therefore supplied exactly non-redundantly.

[0012] "Safety-related energy dissipators" are understood to fulfill safety-related functions, i.e., energy dissipators for safety functions. Such energy dissipators are in particular assigned to a risk category by risk classification according to ISO 26262 (usually IEC 61508), abbreviated "ASIL" (Automotive Safety Integrity Level, English: automotive safety integrity level) and are therefore also referred to simply as "ASIL energy dissipators". Safety-related energy dissipators are used to reliably and operationally safely ensure the safety and in particular the freedom from injury of machines, in particular of vehicles, or of one or more persons, in particular vehicle occupants or other road users, or combinations thereof. Safety-related energy dissipators in vehicles are, for example, braking systems, steering devices, roll stabilization devices, drive systems, chassis control devices, airbags, systems for ensuring vehicle stability and similar safety-related energy dissipators. Safety-related energy dissipators are distinguished from comfort energy dissipators, which do not fulfill safety-related functions but only one or more comfort functions. Such comfort energy dissipators are also assigned to the "QM" class and are therefore also designated as QM energy dissipators. Examples of comfort energy dissipators are air conditioning facilities, seat adjustment devices, audio systems and similar comfort energy dissipators. For safety-related energy dissipators, for example, requirements for redundant energy supply are regularly derived from the cited standards. Such requirements typically do not exist for comfort energy dissipators.

[0013] The vehicle electrical system also has a power module that interconnects the two subnets and is configured in such a way that each of the two supply lines can be connected to two energy sources, so that the energy dissipator can be supplied by the two energy sources via the two supply lines respectively. Thus, this is equivalent to the fact that an energy dissipator on one of the subnets can be supplied from multiple different energy sources connected to the other subnet via at least two different partial networks of the same subnet. Thus, the energy dissipator is not only redundantly connected to a single energy source in the same subnet, but also to energy sources in another subnet. Thus, in addition to the redundancy of the connections, redundancy of the energy sources is also achieved. The energy dissipator can be supplied on the one hand via two independent connection lines and on the other hand also via two independent energy sources.

[0014] The power module as a whole is used to distribute the electrical energy of an energy source to decentralized subnets and partial networks and thus advantageously ensure the described redundant energy supply to the consumers. The power module is configured to distribute electrical energy. The power module is preferably a circuit which, in a purposeful design, has a circuit board on which suitable components for implementing the functionality of the power module are arranged and interconnected. "Electrical energy" is currently particularly understood as the energy for operating the respective consumer, that is to say providing a certain electrical power so that the consumer can perform its function. This is different from electrical signals or controller signals which are only used to transmit data from or to the consumer and do not transmit power and thus are not used for the operation of the consumer.

[0015] The energy source of each respective subnet is directly, in particular only, connected to the same respective subnet and is only indirectly connected to another subnet via the power module. Similarly, this also applies to the following consumers which are directly, respectively only, connected to one subnet but are only indirectly connected to another subnet via the power module. The energy source of each respective subnet is in particular connected to only one partial network of the respective subnet and is thus only indirectly, in particular via the power module, connected to other partial networks. The power module is thus an intermediary or distributor between two subnets and in particular also between two partial networks. The power module is in particular also regarded as the boundary between two subnets and can be said to separate these two subnets from each other. Preferably, the two subnets are only connected to each other via the power module. The consumers are in particular directly connected to at least two partial networks of one of the subnets, thus achieving a redundant connection. Comfort consumers, like the energy source, are in particular connected to only one partial network.

[0016] These embodiments are also meaningfully applicable to designs with a plurality of safety-related consumers which are either all connected to one of the subnets or which are distributed over two subnets. These embodiments are also meaningfully applicable to designs with more than two subnets and also to designs in which a plurality of subnets each have a plurality of partial networks. However, without loss of generality, the case of two subnets and each subnet having two partial networks will be considered first hereinafter. This design is also particularly preferred.

[0017] A significant advantage of the present invention is in particular that each safety-related consumer is supplied via two separate supply lines and can also be supplied from at least two different energy sources via each of the two supply lines. The energy supply to the consumers is thus to a certain extent doubly redundant, that is to say once by means of two supply lines and additionally by means of the supply from two energy sources via each of the two supply lines.

[0018] Another advantage lies especially in that, through a large number of possibilities for powering the energy dissipator, the energy dissipator is especially well protected against fault conditions in one of the subnets or one of the partial networks or components connected thereto, such as a capacitor.

[0019] Especially in the case of a vehicle, the following design is particularly preferred, i.e., in this design, the energy dissipator is connected to the subnet with the higher voltage level among the two subnets. If the first subnet has a lower voltage level, then the energy dissipator is connected to the second subnet, i.e., to the subnet with a higher voltage level compared to the first subnet. Thus, the following design is achieved, in which the safety-related energy dissipator operates at a higher voltage, so that the energy dissipator is optimally protected on the one hand and, on the other hand (compared to the corresponding energy dissipator in the case of a lower voltage), it is also advantageously supplied with a higher power at a lower current.

[0020] The following design is also particularly advantageous, in which the on-vehicle electrical network has at least two safety-related energy dissipators, and the energy dissipators are each connected to the two subnets by the two supply lines described above. In other words: The on-vehicle electrical network has a safety-related first energy dissipator connected to the first subnet, where the first subnet has two partial networks and the first energy dissipator is connected to the two partial networks, so that the first energy dissipator is connected to the energy source of the first subnet via two independent supply lines. The on-vehicle electrical network also has a safety-related second energy dissipator connected to the second subnet, where the second subnet also has two partial networks and the second energy dissipator is connected to the two partial networks, so that the second energy dissipator is connected to the energy source of the second subnet via two independent supply lines. Thus, overall, in each subnet, i.e., at different voltage levels, at least one energy dissipator is redundantly powered.

[0021] In a suitable design, the first subnet has a voltage level of 12V and the second subnet has a voltage level of 48V, and the energy dissipator is connected to the second subnet. Thus, the on-vehicle electrical network has a 12V subnet and a 48V subnet. The energy dissipator is a 48V energy dissipator. Here, it is important that the safety-related energy dissipator operates in the case of the higher voltage level among the two voltage levels and is also especially optimally protected redundantly, as generally described above. The values 12V and 48V here especially refer to the rated voltage and not to the actual voltage that may typically be above or below the rated voltage, such as being higher or lower by up to 10%.

[0022] The respective energy sources are preferably accumulators, in particular batteries or supercapacitors, that is to say supercapacitors. As an energy source, a generator, that is to say an electric machine operating as a generator, is also advantageous. In a preferred design, a first accumulator as the first energy source is connected to a first subnet. A second accumulator as the second energy source and a generator as an additional energy source, for example the vehicle's alternator, are connected to a second subnet. Overall, the on-vehicle electrical network has three energy sources in this design.

[0023] Preferably, the generator and the accumulator are connected to different partial networks of the second subnet. This is not mandatory per se, but has the advantage that the two energy sources of the second subnet are distributed to different partial networks and in the event of a fault in one of the partial networks, potentially only one energy source fails while the other energy sources can continue to be used. The concept of having two energy sources with the energy sources distributed to different partial networks is also advantageous in principle for the first subnet and can also be applied thereto.

[0024] The two subnets are generally in particular DC voltage networks. The power module connects the two subnets and thus also connects the different voltage levels that are accordingly converted by means of the power module. Preferably, in order to supply one subnet with energy from the other subnet and vice versa, the power module has at least one DC transformer that connects the two subnets to each other. The DC transformer is thus used to convert the voltage level. Thus, in a design with a 48V subnet and a 12V subnet, the DC transformer is a 48V / 12V converter. In addition, the DC transformer is the boundary between the first and second subnets.

[0025] The following design is particularly preferred, in which each of the two subnets has two partial networks and in which the power module has two DC transformers, in particular of the same type. The first DC transformer of the two DC transformers connects the first partial network of the first subnet to the first partial network of the second subnet. The second DC transformer of the two DC transformers similarly connects the second partial network of the first subnet to the second partial network of the second subnet. Thus, two partial networks from different subnets are connected via the DC transformers. In this regard, the power module is redundantly constructed in an advantageous manner with respect to the DC transformers. Since the partial networks of the subnets are also connected to each other, each partial network and each consumer connected thereto can continue to be supplied from each other partial network to which an energy source is connected even in the event of a fault in one of the DC transformers. The two DC transformers are also the boundary between the first and second subnets.

[0026] Expediently, the DC transformers are also each used as switches in order to electrically separate the subnets connected thereto from each other in the event of a fault.

[0027] In an advantageous design, the two subnets each have two partial networks and the two partial networks of the first subnet can be separately interconnected via a first switch. Similarly here, the two partial networks of the second subnet can be separately interconnected via a second switch. The switch is especially used to isolate the corresponding partial network in a fault situation, that is to say, if a fault situation occurs in one of the partial networks, this partial network is thereby separated from the remaining partial networks. In addition, that is to say, in normal operation and without a fault situation, the switch is closed in order to interconnect the partial networks accordingly and ensure advantageous redundancy. The switch is, for example, respectively configured as a semiconductor switch or alternatively configured as a relay or a protection device.

[0028] Preferably, the two switches are integrated into the power module, that is to say, the switches are respectively components of the power module. Overall, the switch and the DC transformer are advantageously combined in the power module, so that the overall connection of the partial networks is particularly compact and also spatially concentrated, that is to say, it can be arranged and preferably is arranged in a separate location in the vehicle. Therefore, the components of the power module are not exactly distributed over the vehicle.

[0029] The combination of the design with two switches and the design with two DC transformers is particularly preferred. This results in a power module with a particularly high degree of integration. Here, the switch connects the partial networks within the respective subnet, while the DC transformer interconnects the subnets. In order to achieve maximum redundancy, the partial networks can be interconnected almost arbitrarily by correspondingly switching the switch and the DC transformer and can be separated from each other particularly flexibly in the event of a fault situation. In the case of two subnets each having two partial networks, the first switch connects the partial networks of the first subnet, the second switch connects the partial networks of the second subnet, the first DC transformer connects the two first partial networks of the two subnets and the second DC transformer connects the two second partial networks of the two subnets.

[0030] Thus, a particularly compact design solution is obtained overall because the power module enables the overall connection of the partial networks and subnets to each other and thus also enables redundant supply to the energy consumers. The dual redundant supply to the safety-related energy consumers is preferably fully achieved by the power module, and all functions used here are purposefully integrated into the power module. One function is, in particular, to match the voltage as required in order to supply energy from another subnet to the energy consumers in one subnet. For this purpose, the power module has one or more DC transformers as described. Another function is, in particular, to connect or separate subnets and especially their partial networks from each other as required. For this purpose, the power module has one or more switches as described. The power module itself is particularly compact and is installed, for example, in the engine compartment or in the spare tire well in the trunk of the vehicle instead of the 12V battery. The power module has a particularly high degree of integration.

[0031] Preferably, the power module has its own connection for each partial network, so that the partial networks of the subnet are only connected to each other via the power module and at the energy consumers. The connections are each configured as poles, and the energy consumers of the respective partial network, comfort energy consumers, and energy sources are connected to the poles outside the power module. The connections for the respective subnets are connected, in particular, via switches as described above. DC transformers are arranged between the connections of different subnets as described above. In the case of two subnets each having two partial networks, the power module has a total of four connections. The two subnets are preferably not connected to each other outside the power module. In an advantageous design, the partial networks are also not connected to each other outside the power module.

[0032] In principle, there are two different variants for the arrangement of the respective energy sources, and both variants are advantageous and preferred. In the first variant, the energy source is arranged outside the power module and is constructed separately from the power module, thereby achieving corresponding flexibility. In the second variant, the energy source is integrated into the power module, thereby obtaining a particularly compact design solution. In a particularly preferred design, at least one energy source of the first and second subnets is each configured as an accumulator, that is, for example, configured as a battery or a supercapacitor, and is integrated into the power module. Thus, the power module already provides an energy source in the form of an accumulator for each of the two subnets, so that such an energy source does not have to be additionally connected externally. This achieves a particularly high degree of integration. However, a generator is also connected in a purposeful manner as described above in order to charge the two accumulators.

[0033] In a suitable design, the on-board electrical system has at least one comfort energy dissipator, which is non-safety-related and is connected to one of the energy sources via only one supply line. Thus, the comfort energy dissipator is connected in a non-redundant manner, namely, to only one partial network of only one of the sub-networks.

[0034] This task is also solved by a vehicle having an on-board electrical system or a power module as described above. This task is also solved by the application of the power module in the on-board electrical system as described above and by the application of the power module or the on-board electrical system in the vehicle as described above.

[0035] This task is in particular also solved by a method for operating a power module or an on-board electrical system, wherein, in order to separate two partial networks of a sub-network in the event of a fault situation in one of the partial networks, for example, the switch that electrically connects the two partial networks during normal operation is opened, so that the two partial networks are electrically separated from each other. The above-described embodiments for the on-board electrical system and for the power module are also meaningfully applicable to the method. In particular, advantageous method steps are meaningfully derived from the hitherto described embodiments of the behavior of the on-board electrical system and the power module. Description of the Drawings

[0036] Embodiments of the present invention will be described in detail below with reference to the drawings. Schematically:

[0037] Figure 1 A vehicle having an on-board electrical system is shown;

[0038] Figure 2 Shown Figure 1 A first variant of the on-board electrical system in

[0039] Figure 3 Shown Figure 1 A second variant of the on-board electrical system in Detailed Description of the Invention

[0040] In Figure 1 a vehicle 2 having an on-board electrical system 4 is shown. The on-board electrical system is represented only very schematically by the connecting lines between a plurality of components of the vehicle 2. The vehicle 2 is a motor vehicle, such as a passenger vehicle or a commercial vehicle and is driven, for example, electrically or by an internal combustion engine or by both together. In Figure 2 a first variant of the on-board electrical system 4 is shown in detail, while in Figure 3 a second variant of the on-board electrical system is shown in detail.

[0041] The vehicle electrical system 4 generally has a first sub-network 6 and a second sub-network 8, to which at least one energy source 10, 12, 14 is respectively connected. The first sub-network 6 has a voltage level different from, and currently less than, the voltage level of the second sub-network 8. At least one first energy source 10 is connected to the first sub-network 6 and at least one second energy source 12 is connected to the second sub-network 8. The energy sources 10, 12, 14 of the respective sub-networks 6, 8 define the voltage levels of the respective sub-networks. In the illustrated embodiment, the voltage level of the first sub-network 6 is 12 V, while the voltage level of the second sub-network 8 is 48 V. However, in principle, other voltages are also possible and suitable.

[0042] The vehicle electrical system 4 has at least one and here exemplary are four safety-related consumers 16, which are respectively connected to one of the sub-networks 6, 8. Here, each sub-network 6, 8 has two partial networks 18, 20, 22, 24 and the respective consumers 16 are connected to two partial networks 18, 20, 22, 24 of the respective sub-networks 6, 8, so that the consumers 16 are connected to the energy sources 10, 12, 14 of the respective sub-networks 6, 8 via two independent supply lines V1, V2. This is Figure 2 and Figure 3 exemplarily shown for one of the consumers 16, however it is obvious that all four consumers 16 are respectively independently connected via two connection lines V1, V2. The respective energy sources 10, 12, 14 are only connected to one of the partial networks 18, 20, 22, 24, however, the two partial networks 18, 20, 22, 24 of the respective sub-networks 6, 8 are connected to each other in such a way that the two partial networks 18, 20, 22, 24 are supplied by the respective energy sources 10, 12, 14. Thus, each of the two sub-networks 6, 8 is divided into two partial networks 18, 20, 22, 24, each of which includes a supply line V1, V2, so that the consumers 16 can be supplied via different partial networks 18, 20, 22, 24, that is, connected redundantly to the energy sources 10, 12, 14. In contrast, one or more optionally present comfort consumers 26 are only connected to a single partial network 18, 20, 22, 24, that is, are supplied exactly non-redundantly.

[0043] The safety-related consumers 16 respectively fulfill safety-related functions and are used to reliably and operationally safely ensure the safety and undamaged state of the vehicle 2 or the safety and undamaged state of one or more occupants of the vehicle 2 or other road users. The safety-related consumers of the vehicle are, for example, in Figure 1As shown, it is a braking system or a steering device, or alternatively or additionally, in a variant not shown, it is a roll stabilization device, a drive system, a chassis control device, an airbag, or a system for ensuring vehicle stability, as well as similar energy dissipators. The safety-related energy dissipator 16 is distinguished from the comfort energy dissipator 26, which does not satisfy safety-related functions but only one or more comfort functions. An example of the comfort energy dissipator 26 is, as can be seen in Figure 1 a seat adjustment device, or alternatively or additionally, also an air conditioning facility, an audio system, or a similar energy dissipator.

[0044] The vehicle electrical system 4 also has a power module 28 that interconnects the two subnets 6, 8 and is configured in such a way that each of the two supply lines V1, V2 can be connected to all the energy sources 10, 12, 14, so that the energy dissipator 16 can be supplied by all the energy sources 10, 12, 14 via the two supply lines V1, V2, respectively. Thus, the energy dissipator 16 is not only redundantly connected to the individual energy sources 10, 12, 14 in the same subnets 6, 8, but also to one or more energy sources 10, 12, 14 from the other subnets 6, 8. Therefore, in addition to connection redundancy, energy supply redundancy is also achieved.

[0045] The power module as a whole is used to distribute the electrical energy of the energy sources 10, 12, 14 to the decentralized subnets 6, 8 and partial networks 18, 20, 22, 24 and thus ensure the described energy supply redundancy for the energy dissipator 16. The power module 28 in the illustrated embodiment is a circuit, which here is a circuit board 30, on which suitable components for implementing the functionality of the power module 28 are arranged and interconnected.

[0046] Each respective energy source 10, 12, 14 is only directly connected to one of the subnets 6, 8 and is only indirectly connected to the other subnets 6, 8 via the power module 28. Similarly, the same also applies to the energy dissipator 16 and the comfort energy dissipator 26, which are each only directly connected to one of the subnets 6, 8 and are only indirectly connected to the other subnet 6, 8 via the power module 28. In addition, each respective energy source 10, 12, 14 is also only connected to one of the partial networks 18, 20, 22, 24 and is thus only indirectly connected to the remaining partial networks 18, 20, 22, 24, i.e., via the power module 28. While each respective energy dissipator 16 is directly connected to at least two of the partial networks 18, 20, 22, 24 of one of the subnets 6, 8, thus achieving a redundant connection. While each respective comfort energy dissipator 26 is only connected to one partial network 18, 20, 22, 24.

[0047] As already described, inFigure 2 and Figure 3 In Figure 2 and Figure 3 , the first subnet 6 has a voltage level of 12 V and the second subnet 8 has a relatively higher voltage level of 48 V. In particular, at least one safety-related energy consumer 16 is connected to the second subnet 8 and operates at the higher voltage and is supplied with energy redundantly. In principle, this is independent of which and how many energy consumers 16 and comfort energy consumers 26 are connected to the first subnet at 12 V and also independent of how the energy sources 10, 12, 14 are distributed.

[0048] The energy sources 10, 12 are currently each configured as accumulators, and in this case even as batteries. Alternatively, a design configured as a supercapacitor is also suitable. A generator is also suitable as the energy source 14. In the illustrated embodiment, the first accumulator as the first energy source 10 is connected to the first subnet 6 and the second accumulator as the second energy source 12 and the generator as the additional energy source 14 are connected to the second subnet 8, so that the vehicle electrical system 4 shown has three energy sources 10, 12, 14 each. Alternative configurations with other numbers and distributions of the energy sources 10, 12, 14 are in principle also possible and suitable, provided that at least one energy source 10, 12, 14 is connected to each of the subnets 6, 8, so that there is at least one energy source 10, 12, 14 for each subnet 6, 8.

[0049] In Figure 2 and Figure 3 's embodiment, the generator 14 and the second accumulator 12 are connected to different partial networks 22, 24 of the second subnet 8. This is not mandatory per se, but has the advantage that the two energy sources 12, 14 of the second subnet 8 are assigned to different partial networks 22, 24 and in the event of a fault in one of the partial networks 22, 24, only one of the energy sources 12, 14 may fail while the other energy source can still be used. This concept can similarly also be applied to the first subnet 6.

[0050] The power module 28 connects the two subnets 6, 8 and thus also connects the different voltage levels. In order to supply one subnet 6, 8 with energy from the other subnet 6, 8 and vice versa, the power module 28 has at least one and in this case two DC transformers 32, 34, and the two subnets 6, 8 are connected to each other via the DC transformers. The DC transformers 32, 34 are used to convert the voltage levels and are in this case specifically each configured as a 48 V / 12 V converter. The DC transformers 32, 34 are also the boundary between the two subnets 6, 8.

[0051] In accordance with Figure 2 and Figure 3In the design solution, the first subnet 6 has a first partial network 18 and a second partial network 20, and the second subnet 8 similarly has a first partial network 22 and a second partial network 24. The first DC transformer 32 connects the first partial network 18 of the first subnet 6 to the first partial network 22 of the second subnet 8. The second DC transformer 34 similarly connects the second partial network 20 of the first subnet 6 to the second partial network 24 of the second subnet 8. Thus, on the one hand, the first partial networks 18, 22 and the second partial networks 20, 24 are connected via their respective DC transformers 32, 34. Since the partial networks 18, 20, 22, 24 of the subnets 6, 8 are also connected to each other, each partial network 18, 20, 22, 24 and each energy consumer 16 connected thereto can still continue to be supplied from each other partial network 18, 20, 22, 24 to which an energy source 10, 12, 14 is connected, even in the case of a failure of one of the DC transformers 32, 34.

[0052] The two partial networks 18, 20 of the first subnet 6 can be separately connected to each other via the first switch 36. Similarly, the two partial networks 22, 24 of the second subnet 8 can also be separately connected to each other via the second switch 38. The switches 36, 38 are used to separate the respective partial networks 18, 20, 22, 24 in the event of a failure by opening the corresponding switches 36, 38. In addition, that is, in the case of normal operation without a failure, the switches 36, 38 are, conversely, closed. In the illustrated embodiment, the two switches are integrated into the power module 28, that is, integrated on the circuit board 30. In a variant not shown, the DC transformers 32, 34 are also mounted on the circuit board 30.

[0053] As can be clearly seen from Figure 2 and 3 it is obvious that the switches 36, 38 connect the respective first partial networks 18, 22 to the second partial networks 20, 24 belonging within the same subnets 6, 8, while the DC transformers 32, 34 connect the different subnets 6, 8 to each other. By corresponding switching of the switches 36, 38 and the DC transformers 32, 34, the partial networks 18, 20, 22, 24 can be connected to each other and separated from each other almost arbitrarily.

[0054] Currently, the power module 28 has its own connection 40 for each partial network 18, 20, 22, 24. Thus, the partial networks 18, 20, 22, 24 of the subnets 6, 8 are only interconnected via the power module 28 and at the energy dissipator 16. The connections 40 are each configured as poles, and the energy dissipators 16, comfort energy dissipators 26 and energy sources 10, 12, 14 of the respective partial networks 18, 20, 22, 24 are connected to said poles outside the power module 28. The connections 40 of the respective subnets 6, 8 are connected via one of the switches 36, 38. And one of the DC transformers 32, 34 is arranged between two connections 40 of different subnets 6, 8.

[0055] The respective energy sources 10, 12, 14 are either arranged outside and independently of the power module 28 as shown in Figure 2 or alternatively integrated into the power module 28 as shown in Figure 3 . In particular, in Figure 3 , the energy sources 10, 12 configured as accumulators are integrated into the power module 28, while the generator 14 is arranged outside the power module 28 as in Figure 2 . Thus, Figure 3 the power module 28 has energy sources 10, 12 in the form of accumulators for each of the two subnets 6, 8, so that such energy sources do not have to be additionally connected externally.

[0056] List of reference numerals

[0057] 2 Vehicle

[0058] 4 On-vehicle electrical network

[0059] 6 First subnet (12 V)

[0060] 8 Second subnet (48 V)

[0061] 10 First energy source, first accumulator

[0062] 12 Second energy source, second accumulator

[0063] 14 Energy source, generator

[0064] 16 Safety-related energy dissipator

[0065] 18 First partial network (in the first subnet)

[0066] 20 Second partial network (in the first subnet)

[0067] 22 First partial network (in the second subnet)

[0068] 24 Second partial network (in the second subnet)

[0069] 26 Comfort energy dissipator

[0070] 28 Power module

[0071] 30 Circuit board

[0072] 32 First DC transformer

[0073] 34 Second DC transformer

[0074] 36 First switch

[0075] 38 Second switch

[0076] 40 Connection part

[0077] V1, V2 connection line

Claims

1. A vehicle electrical network (4), - The vehicle electrical network is configured for use in a vehicle (2), - The vehicle electrical network has a first sub-network (6) and a second sub-network (8), with at least one energy source connected to the first sub-network and the second sub-network respectively, Wherein, The voltage level of the first sub-network (6) is different from the voltage level of the second sub-network (8), - The vehicle electrical network has at least one safety-related energy dissipator (16), which is connected to one of the sub-networks, and wherein this sub-network has two partial networks and the energy dissipator (16) is connected to the two partial networks, so that the energy dissipator (16) is connected to the energy source of the sub-network via two independent supply lines (V1, V2), - The vehicle electrical network has a power module (28), which connects the two sub-networks (6, 8) to each other and is constructed in such a way that each of the two supply lines (V1, V2) can be connected to two energy sources, so that the energy dissipator (16) can be supplied by two energy sources via the two supply lines (V1, V2) respectively, Wherein, the two sub-networks (6, 8) each have two partial networks, and wherein the power module (28) has two DC transformers (32, 34), and the two DC transformers are the boundaries between the first and second sub-networks (6, 8), Wherein, the first DC transformer (32) of the two DC transformers connects the first partial network (18) of the first sub-network (6) to the first partial network (22) of the second sub-network (8), Wherein, the second DC transformer (34) of the two DC transformers connects the second partial network (20) of the first sub-network (6) to the second partial network (24) of the second sub-network (8), so that the corresponding two partial networks from different sub-networks (6, 8) are connected via the DC transformers (32, 34).

2. The vehicle electrical network (4) according to claim 1, Wherein, The energy source of each sub-network is directly connected only to that sub-network and is only indirectly connected to the other sub-network via the power module (28), Wherein, the energy dissipator (16) is directly connected only to one sub-network and is only indirectly connected to the other sub-network via the power module (28).

3. The vehicle electrical network (4) according to claim 1 or 2, Wherein, The voltage level of the first sub-network (6) is less than the voltage level of the second sub-network (8).

4. The vehicle electrical network (4) according to any one of claims 1 to 2, Wherein, The energy dissipator (16) is connected to the sub-network among the two sub-networks (6, 8) that has a higher voltage level.

5. The vehicle electrical network (4) according to any one of claims 1 to 2, Wherein, The first sub-network (6) has a voltage level of 12V and the second sub-network (8) has a voltage level of 48V, and wherein the energy dissipator (16) is connected to the second sub-network (8).

6. The vehicle electrical system (4) according to any one of claims 1 to 2, wherein, a first electrical energy storage device as a first energy source (10) is connected to the first sub-network (6), and wherein a second electrical energy storage device as a second energy source (12) and a generator as an additional energy source (14) are connected to the second sub-network (8).

7. The vehicle electrical system (4) according to claim 6, wherein, the generator and the second electrical energy storage device are connected to different partial networks (22, 24) of the second sub-network (8).

8. The vehicle electrical system (4) according to any one of claims 1 to 2, wherein, the power module (28) has at least one DC transformer (32, 34), and the two sub-networks (6, 8) are interconnected via the DC transformer in order to supply energy from one sub-network to the other sub-network and vice versa.

9. The vehicle electrical system (4) according to any one of claims 1 to 2, wherein, the two sub-networks (6, 8) each have two partial networks, wherein the two partial networks (18, 20) of the first sub-network (6) are separably interconnected via a first switch (36), and wherein the two partial networks (22, 24) of the second sub-network (8) are separably interconnected via a second switch (38).

10. The vehicle electrical system (4) according to claim 9, wherein, the two switches (36, 38) are integrated into the power module (28).

11. The vehicle electrical system (4) according to any one of claims 1 to 2, wherein, the power module (28) has its own connection portion (40) for each partial network (18, 20, 22, 24).

12. The vehicle electrical system (4) according to any one of claims 1 to 2, wherein, at least one energy source of each of the first sub-network (6) and the second sub-network (8) is configured as an electrical energy storage device and integrated into the power module (28).

13. The vehicle electrical system (4) according to any one of claims 1 to 2, wherein, the vehicle electrical system has at least one comfort energy consumer (26), the comfort energy consumer is not safety-related and the comfort energy consumer is connected to only one of the energy sources via a supply line.

14. A power module (28) for a vehicle electrical system (4) according to any one of claims 1 to 13.

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