Electrical system for a vehicle

Abstract

Electrical system (1) for a vehicle with - a first partial on-board network (2), - a second sub-system (3) connected or switchable in parallel to the first sub-system (2), wherein an electrical energy storage device (9) is arranged in the second sub-system (3), - a DC / DC converter (4) whose output is electrically coupled to the first sub-system (2), - a safety separating element (5) arranged between the first sub-system (2) and the second sub-system (3), which in a first state electrically connects the first and second sub-system (2, 3) to each other and in a second state electrically separates the first and second sub-system (2, 3) from each other, and - a control unit which is designed at least to control the safety separating element (5), characterized in that the control unit is further designed to receive crash signals and fault signals detected by means of vehicle-specific sensors, and in the presence of such crash signals and fault signals to control the safety separating element (5) in such a way that the first and the second sub-network (2, 3) are electrically separated from each other.

Description

[0001] The invention relates to an electrical on-board network for a vehicle according to the preamble of claim 1.

[0002] A power supply system for an electric vehicle is disclosed in DE 10 2018 214 759 A1. The power supply system comprises - a first subnetwork with a first nominal voltage, - a second subnetwork with a second nominal voltage, - a third subnetwork with a third nominal voltage, - a fourth subnetwork with a fourth nominal voltage, - a first DC-DC converter for coupling the first subnetwork with the second subnetwork, - a second DC-DC converter for coupling the first subnetwork with the third subnetwork, - a third DC-DC converter for coupling the second subnetwork with the third subnetwork and - a fourth DC-DC converter for coupling the second subnetwork with the fourth subnetwork.

[0003] Furthermore, an electrical system for a vehicle is known from DE 10 2022 001 268 A1. The electrical system comprises a primary network and a primary battery, with two or more low-voltage networks connected to the primary network via respective DC / DC converters. Each low-voltage network has one or more low-voltage loads, and one of the low-voltage networks has its own low-voltage battery. The primary network is designed as a high-voltage network, and the primary battery is also designed as a high-voltage battery. A switch is also provided for selectively disconnecting or connecting the primary battery to the primary network.DE 10 2019 112 706 A1 describes a method and a device for supplying energy to an electrical consumer of a vehicle, DE 10 2021 103 954 A1 shows an on-board network and a method for operating an on-board network, and DE 10 2019 105 504 A1 describes an energy network for a motor vehicle and a method for operating an energy network for a motor vehicle. In DE 10 2024 000 872 A1, an on-board electrical system for a vehicle is described, comprising a high-voltage on-board electrical system with a high-voltage battery (HVB) and a low-voltage section with an on-board electrical system channel (EBN) which is designed as a comfort on-board electrical system (EBN), wherein the comfort on-board electrical system (EBN) is connected to the high-voltage on-board electrical system via a DC / DC converter and is configured to supply static loads, wherein a low-voltage battery is arranged in the comfort on-board electrical system (EBN), and wherein the on-board electrical system is designed to be expandable by means of further on-board electrical system channels.

[0004] The present invention is based on the objective of providing a novel electrical on-board network for a vehicle.

[0005] The problem is solved according to the invention by an electrical on-board network which has the features specified in claim 1.

[0006] Possible embodiments of the invention are the subject of the dependent claims.

[0007] An electrical system for a vehicle comprises a first sub-system, a second sub-system which is electrically connected or switchable in parallel to the first sub-system, and a DC / DC converter, the output of which is electrically coupled to the first sub-system.

[0008] According to the invention, a safety isolating element is arranged between the first and second sub-wiring systems. In a first state, this element electrically connects the first and second sub-wiring systems, and in a second state, it electrically disconnects them. An electrical energy storage device is arranged in the second sub-wiring system.

[0009] Due to the electrically switchable connection provided by the safety disconnect element, the present electrical system allows for the electrical isolation of the first and second sub-systems in the event of a fault. Furthermore, the energy storage system located in the second sub-system ensures an independent power supply to the electrical consumers in both sub-systems during such a fault. This allows compliance with Automotive Safety Integrity Levels (ASIL). Additionally, in the first state of the safety disconnect element, i.e., when the two sub-systems are electrically connected, continuous charging of the energy storage system is possible.

[0010] Furthermore, the safety isolating element and the energy storage system eliminate the need for a separate DC-DC converter to supply the second sub-network, resulting in weight, cost, and space savings. Simultaneously, no separate energy storage system is required to operate the first sub-network, again resulting in weight, cost, and space savings. The first sub-network can be electrically supplied by the DC-DC converter, which is designed to be highly dynamic and highly available. Due to its coupling with the second sub-network, the energy storage system in the second sub-network provides an intelligent mechanism for reducing the start-up times of electrical consumers, such as electronic control units, in the first sub-network, which lacks its own energy storage.

[0011] Furthermore, the design of the on-board electrical system with the safety disconnect and the energy storage device allows for a minimization of the number of semiconductor switches required for power distribution, resulting in cost and complexity advantages. Each power distribution unit can also be equipped with fuses, subject to specific load configurations and the safety disconnect.

[0012] According to one possible configuration of the electrical system, the first and second sub-systems are designed to provide a redundant power supply for safety-critical electrical consumers essential for vehicle operation. This ensures a reliable power supply for electrical consumers requiring redundancy, thus meeting high ASIL requirements. Homogeneous redundancy, such as the need for a separate energy storage system for each sub-system, can be avoided, as both the energy storage system of the second sub-system and the directly coupled DC-DC converter serve as the backup power source. This approach prevents dependent faults, particularly common-cause and cascading faults.

[0013] According to another possible configuration of the electrical system, it includes a third sub-network and an additional DC-DC converter, the output of which is electrically coupled to the third sub-network. For example, the third sub-network is designed to supply power to electrical consumers intended for comfort functions. This configuration separates the safety-relevant electrical consumers in the first and second sub-networks from those intended for comfort functions. This, in turn, means that the additional DC-DC converter coupled to the third sub-network and the electrical consumers in the third sub-network do not need to meet stringent safety or availability requirements, resulting in cost and complexity reductions.This eliminates the need for complex safety mechanisms that, according to VDA 450, must be implemented in a mixed electrical system channel, i.e., a sub-system containing both comfort functions and safety-related electrical consumers. Furthermore, the potential separation of the electrical supply for safety and comfort functions can also relieve the load on the energy storage system located in the second sub-system, as this separation results in a significantly lower "worst-case load" according to VDA 450. Additionally, this separation ensures that the third sub-system does not affect the first and second sub-systems.

[0014] According to another possible configuration of the electrical system, an electrical energy storage device is arranged in the third sub-system. This device ensures that the electrical loads in the third sub-system continue to be supplied with electricity even if the third sub-system is disconnected from the power supply. Advantageously, due to the potential separation from the first and second sub-systems and the energy storage device located in the second sub-system, the energy storage device does not need to meet stringent safety or availability requirements.

[0015] According to another possible configuration of the electrical system, a coupling element is arranged between the third and first sub-systems. In a first state, this element electrically connects the third and first sub-systems, and in a second state, it electrically isolates them. Such isolation reduces the energy demands placed on the energy storage device in the third sub-system, as high energy demands on the storage device, for example, to ensure a 60-minute warning light flashing sequence after a crash, can be met by the highly available DC-DC converter of the first sub-system or the energy storage device of the second sub-system.Furthermore, the coupling element enables efficiency-optimized pre-charging of the DC-DC converter connected to the first sub-system by using power-controlled mechanisms. This is achieved by supplying energy from the energy storage device of the third sub-system to the DC-DC converter via the coupling element. Increased energy efficiency can also be achieved because the DC-DC converter connected to the first sub-system can be used for certain processes instead of the DC-DC converter connected to the third sub-system. This is particularly relevant when the DC-DC converter connected to the first sub-system is directly coupled to a high-voltage electrical energy storage device within a high-voltage electrical system, as this direct coupling eliminates the need to energize the entire high-voltage electrical system to operate the DC-DC converter.Such an increase in energy efficiency is advantageous, for example, when recharging the energy storage unit located in the third sub-system while the vehicle is parked. Furthermore, with the coupling element closed, an increase in energy efficiency can be achieved through a bidirectional feed-in option in the high-voltage electrical system.

[0016] According to another possible configuration of the electrical system, it features a high-voltage electrical system which is coupled, or can be coupled, to at least one high-voltage electrical energy storage device. This high-voltage electrical system enables the supply of high-voltage power to the vehicle's electrical consumers.

[0017] According to another possible configuration of the electrical system, the DC-DC converter connected to the first sub-system is coupled with its input to the high-voltage energy storage system. Such a direct connection of the first and second sub-systems to the high-voltage energy storage system increases the availability of power to the electrical consumers in both sub-systems. Furthermore, this direct connection eliminates the need to shut down the first and second sub-systems after a vehicle crash, particularly if the high-voltage energy storage system is disconnected from the high-voltage system by a switching element.

[0018] According to another possible configuration of the electrical system, the additional DC-DC converter connected to the third sub-system is coupled to the high-voltage system via its input. In particular, the DC-DC converter connected to the first sub-system is also at least indirectly coupled to the high-voltage system via the high-voltage energy storage device. This enables the DC-DC converters to be powered. The first, second, and third sub-systems are each specifically designed as low-voltage systems.

[0019] According to the invention, the electrical system includes a control unit configured to control at least the safety isolating element. The control unit can also be configured to control the coupling element. In particular, the control unit is further configured to receive crash signals and fault signals, such as signals relating to electrical faults in the electrical system, detected by means of vehicle-integrated sensors and, upon the presence of such signals, to control the safety isolating element and / or the coupling element in such a way that the sub-systems can be electrically isolated from one another. In another possible embodiment of the electrical system, the safety isolating element and / or coupling element are configured as mechanical switches, electromagnetic relays, or semiconductor switches.

[0020] According to another possible design of the electrical on-board network, the coupling element and / or the safety disconnect element are designed as a fuse or semiconductor fuse and trigger automatically in the event of excessive current flow.

[0021] According to another possible configuration of the electrical system, it can have further sub-systems which can be separated from each other or coupled together by means of safety isolating elements and / or coupling elements. This allows for the creation of a modular and scalable architecture that can be easily adapted, for example, to different vehicle configurations with varying electrical comfort and / or safety consumers. In this way, the complexity of the electrical system can be adapted to and minimized according to specific requirements.

[0022] Exemplary embodiments of the invention are explained in more detail below with reference to drawings.

[0023] This shows: Fig. 1 schematically an embodiment of a vehicle's electrical system, Fig. 2 schematically another embodiment of a vehicle electrical system, Fig. 3 schematically shows another embodiment of a vehicle's electrical system, Fig. 4 schematically shows another embodiment of a vehicle's electrical system, Fig. 5 schematically another embodiment of a vehicle electrical system and Fig. 6 schematically shows another embodiment of a vehicle electrical system.

[0024] Corresponding parts are marked with the same reference symbols in all figures.

[0025] In Fig. Figure 1 shows a possible embodiment of a vehicle electrical system 1. The electrical system 1 comprises a first sub-system 2, a second sub-system 3, a DC / DC converter 4, and a safety disconnect device 5.

[0026] The two sub-systems 2 and 3 are specifically designed as low-voltage systems and are intended for a redundant electrical supply of the same electrical consumers 6.1 to 6.n. The nominal voltage of sub-systems 2 and 3 is, for example, 12 volts. In particular, sub-systems 2 and 3 are safety systems designed for a redundant electrical supply of electrical consumers 6.1 to 6.n that are safety-relevant for the operation of the vehicle.

[0027] Electrical consumers 6.1 to 6.n are used, for example, to operate the steering, brakes, lighting, automated driving functions of the vehicle, etc. Electrical consumers 6.1 to 6.n include, for example, control units. Both sub-networks 2 and 3 each comprise, in a manner not shown in detail, several power distribution units with semiconductor fuses for connecting the electrical consumers 6.1 to 6.n to the respective sub-network 2 and 3. Depending on the existing safety concept, fuse links may also be used instead of power distribution units with semiconductor fuses.

[0028] The DC-DC converter 4 is coupled to an energy source on its input side in a manner not shown in detail and converts a source voltage into a lower low voltage for the two sub-networks 2, 3. The energy source is, for example, a [missing information - likely a component] in the Fig. 2 to 6, a high-voltage energy storage device shown in more detail, and / or a high-voltage energy storage device also shown in the Fig. 2 to 6, high-voltage electrical system shown in more detail. 8.

[0029] On the output side, the DC-DC converter 4, which is designed to be particularly highly dynamic and highly available, is electrically coupled to the first sub-system 2 and supplies it with power. In particular, the DC-DC converter 4 is designed to supply all static and dynamic electrical loads in the first sub-system 2.

[0030] The safety isolating element 5 is arranged between the first sub-system 2 and the second sub-system 3 and, in a first state, electrically connects the first and second sub-systems 2, 3 to each other, so that the second sub-system 3 is also electrically coupled to the output of the DC-DC converter 4. This enables bidirectional current flow between the sub-systems 2, 3.

[0031] In the second sub-network 3, an electrical energy storage device 9 is arranged, which is electrically charged in the first state of the safety disconnect element 5 and is therefore highly available. In particular, the energy storage device 9 is designed to supply all static and dynamic electrical loads in the second sub-network 3.

[0032] In a second state, the safety disconnect element 5 electrically isolates the first and second sub-systems 2, 3 from each other. The safety disconnect element 5 is switched to this second state, for example, if voltage and / or current values ​​fall below or exceed predefined limits, or if the power source coupled to the DC-DC converter 4 fails, such as due to an electrical fault or disconnection of the power source from the DC-DC converter 4. Disconnection of the power source from the DC-DC converter 4 occurs, for example, after a vehicle crash if the power source is configured as a high-voltage energy storage device 7 or a high-voltage electrical system 8, in order to prevent the application of potentially lethal high voltage to vehicle body parts, as well as electrical faults and resulting damage to the vehicle and its surroundings.

[0033] In one possible embodiment, the DC-DC converter 4 is directly coupled to the energy source, which is designed as a high-voltage energy storage device 7. This prevents the DC-DC converter 4 from being disconnected from the energy source in the event of a crash, thus advantageously allowing both sub-networks 2 and 3 to continue receiving electrical energy even in the event of faults in the high-voltage network 8. This results in an increase in the availability of sub-networks 2 and 3 and the consumers 6.1 to 6.n located within them.

[0034] For the automatic control of the safety isolating element 5, a control unit (not shown in detail) is provided. According to the invention, the control unit is designed to receive crash signals and fault signals detected by means of vehicle-integrated sensors, for example, signals relating to electrical faults in the vehicle electrical system 1, and, when such signals are present, to control the safety isolating element 5 in such a way that the sub-electrical electrical systems 2 and 3 can be electrically separated from each other.

[0035] Due to the electrical energy storage device 9 present in the second sub-network 3, the electrical supply of consumers 6.1 to 6.n can be ensured even when the two sub-networks 2, 3 are separated / separated.

[0036] Fig. Figure 2 shows another possible embodiment of a vehicle electrical system 1. The vehicle electrical system 1 comprises a high-voltage electrical system 8 and a high-voltage electrical energy storage device 7, which can be selectively coupled to or disconnected from the high-voltage electrical system 8 via a switching element 10.

[0037] A further DC-DC converter 11 is coupled to the high-voltage electrical system 8. A third sub-electrical system 12 is electrically coupled to an output of the DC-DC converter 11, with the DC-DC converter 11 being intended to supply all static loads in the third sub-electrical system 12. The third sub-electrical system 12 is, in particular, a low-voltage electrical system, with a nominal voltage of the third sub-electrical system 12 being, for example, 12 volts.

[0038] The third sub-network 12, for example, is designed as a comfort network for the electrical supply of electrical consumers 13.1 to 13.m intended for comfort functions of the vehicle. Such comfort functions include, for example, seat heating, interior lighting, seat ventilation, seat massage, an entertainment system, etc. In addition, the third sub-network 12 can also supply other electrical consumers 13.1 to 13.m not intended for comfort functions.

[0039] In a manner not shown in detail, the third sub-system 12 comprises several power distributors with fuse links or semiconductor fuses for connecting the electrical consumers 13.1 to 13.m to the third sub-system 12.

[0040] Furthermore, an electrical energy storage device 14 is arranged in the third sub-system 12, which is electrically charged by means of the DC-DC converter 11. In particular, the energy storage device 14 is configured to supply all dynamic electrical loads, i.e., dynamic processes and operating states, in the third sub-system 12 when the DC-DC converter 11 is deactivated.

[0041] The illustrated embodiment of the vehicle electrical system 1 represents a first module of a scalable or modular vehicle electrical system structure, which is implemented depending on various vehicle characteristics, equipment and / or safety requirements of the vehicle.

[0042] In the illustrated embodiment of the vehicle electrical system 1, the third sub-system 12, designed as a low-voltage electrical system, fulfills, for example, only minimal safety requirements without redundancy requirements. Such a vehicle electrical system 1 is used, for example, in a light and small vehicle without redundancy requirements for electrical systems and with maximum safety requirements up to Automotive Safety Integrity Level B (ASIL B).

[0043] In Fig. Figure 3 shows another possible embodiment of a vehicle electrical system 1. Building on the one in Fig. In the embodiment of the electrical system 1 shown in section 2, this includes, in addition to the third sub-electrical system 12, a further module which is located in Fig. 1 first sub-network 2 shown and designed according to the associated description, which is electrically coupled via the DC voltage converter 4 to the high-voltage energy storage 7 and, when the switching element 10 is closed, to the high-voltage on-board network 8.

[0044] The third sub-network 12 is designed, for example, as a pure comfort network and the first sub-network 2 as a pure safety network.

[0045] In the illustrated embodiment of the on-board network 1, the separation of the two sub-on-board networks 2, 12 and thus the separation of the comfort consumers from the safety consumers results in higher safety requirements than in the embodiment according to Fig. 2, but also fulfills redundancy requirements. Such a wiring harness 1 is used, for example, in a heavy vehicle without redundancy requirements for electrical systems and with maximum safety requirements up to "Automotive Safety Integrity Level" C (abbreviated "ASIL" C).

[0046] Fig. Figure 4 shows another possible embodiment of a vehicle electrical system 1. Building on the one in Fig. In the embodiment of the electrical system 1 shown in section 3, this system comprises, in addition to the first and third sub-systems 2, 12, a further module which is located in Fig. 1. Second sub-network 3 shown and designed according to the associated description, which can be coupled to or disconnected from the first sub-network 2 via the safety separating element 5.

[0047] The third sub-system 12 is designed, for example, as a pure comfort system, while the first and second sub-system 2, 3 are designed as pure safety systems and for the redundant supply of the same safety-relevant electrical consumers 6.1 to 6.n.

[0048] In the illustrated embodiment of the vehicle electrical system 1, the separation of the first and second sub-systems 2, 3 from the third sub-systems 12 and the redundant supply of the safety-relevant electrical consumers 6.1 to 6.n result in higher safety requirements than in the embodiment according to Fig. 3 and redundancy requirements are met. Such a designed on-board network 1 is used, for example, in a heavy vehicle with redundancy requirements for electrical systems and maximum safety requirements reaching, for example, up to the "Automotive Safety Integrity Level" D (abbreviated "ASIL" D).

[0049] Furthermore, due to the separation of the first and second sub-network 2, 3 from the third sub-network 12, the third sub-network 12 can be extended by any number of additional electrical consumers 13.1 to 13.m without having to adjust the dimensioning of the energy storage 9 present in the second sub-network 3.

[0050] In Fig. Figure 5 shows another possible embodiment of a vehicle electrical system 1. In addition to the one shown in Fig. In the embodiment shown in Figure 3, a coupling element 15 is arranged between the third sub-system 12 and the first sub-system 2. In a first state, this coupling element electrically connects the third and first sub-systems 12, 2, and in a second state, it electrically disconnects them. The control unit also provided for controlling the safety disconnect element 5, or a further control unit not shown, is used for automatic control of the coupling element 15.

[0051] Opening the coupling element 15 allows for a reduction in energy requirements for the energy storage device 14 in the third sub-network 12, since high demands on the energy content of the energy storage device 14, for example, to ensure a 60-minute warning light flashing after a crash, can be met by the highly available DC-DC converter 4 of the first sub-network 2. Because this is directly coupled to the high-voltage energy storage device 7, no shutdown is required after a crash.

[0052] Furthermore, precharging the DC voltage converter 4 is simplified by supplying energy from the energy storage device 14 of the third sub-network 12 to the DC voltage converter 4 via the closed coupling element 15.

[0053] In addition, energy efficiency can be increased because the DC-DC converter 4 can be used instead of the DC-DC converter 11 for certain processes. The direct connection of the DC-DC converter 4 to the high-voltage energy storage device 7 means that the entire high-voltage electrical system 8 does not need to be powered.

[0054] Fig. Figure 6 shows another possible embodiment of a vehicle electrical system 1. Building on the one in Fig. In the exemplary embodiment of the electrical system 1 shown in Figure 5, this system comprises, in addition to the first and third sub-systems 2, 12, a further module which is located in Fig. 1. Second sub-network 3 shown and designed according to the associated description, which can be coupled to or disconnected from the first sub-network 2 via the safety separating element 5.

[0055] In addition to the advantages of the in Fig.In the embodiment shown in Figure 5, the direct connection of the DC voltage converter 4 to the high-voltage energy storage device 7 and the resulting elimination of the need to supply current to the entire high-voltage electrical system 8 allows, for example, energy-efficient recharging of the energy storage device 9 in the second sub-electrical network 3 when the vehicle is parked. Reference symbol list 1 On-board electrical system 2 first sub-network 3 second partial on-board network 4 DC-DC converters 5 safety separating element 6.1 to 6.n Consumers 7 high-voltage energy storage systems 8 High-voltage electrical system 9 Energy storage 10 switching element 11 DC / DC converters 12 third sub-network 13.1 to 13.m Consumer 14 Energy storage 15 coupling element

Claims

[1] Electrical system (1) for a vehicle with - a first partial on-board network (2), - a second sub-system (3) connected or switchable in parallel to the first sub-system (2), wherein an electrical energy storage device (9) is arranged in the second sub-system (3), - a DC / DC converter (4) whose output is electrically coupled to the first sub-system (2), - a safety separating element (5) arranged between the first sub-system (2) and the second sub-system (3), which in a first state electrically connects the first and second sub-system (2, 3) to each other and in a second state electrically separates the first and second sub-system (2, 3) from each other, and - a control unit which is designed at least to control the safety separating element (5), characterized by, that the control unit is further designed to receive crash signals and fault signals detected by means of vehicle-specific sensors, and in the presence of such crash signals and fault signals to control the safety isolating element (5) in such a way that the first and the second sub-network (2, 3) are electrically separated from each other. [2] Electrical on-board network (1) according to claim 1, characterized by , that the first sub-network (2) and the second sub-network (3) are designed to provide a redundant electrical supply for safety-relevant electrical consumers (6.1 to 6.n) for the operation of the vehicle. [3] Electrical on-board network (1) according to claim 1 or 2, characterized by - a third partial on-board network (12) and - a further DC voltage converter (11), which is electrically coupled to the third sub-network (12) via its output. [4] Electrical on-board network (1) according to claim 3, characterized by, that a coupling element (15) is arranged between the third sub-system (12) and the first sub-system (2), which in a first state electrically connects the third and first sub-system (12, 2) and in a second state electrically separates the third and first sub-system (12, 2) from each other. [5] Electrical on-board network (1) according to claim 3 or 4, characterized by , that an electrical energy storage device (14) is arranged in the third sub-network (12). [6] Electrical on-board network (1) according to any one of claims 3 to 5, characterized by , that the third sub-network (12) is designed to provide electrical power to electrical consumers (13.1 to 13.m) intended for comfort functions. [7] Electrical on-board network (1) according to any one of the preceding claims, characterized by a high-voltage electrical system (8) which is coupled or can be coupled to at least one high-voltage electrical energy storage device (7). [8] Electrical on-board network (1) according to claim 7, characterized by , that the DC voltage converter (4) coupled to the first sub-network (2) is coupled with its input to the electrical high-voltage energy storage device (7). [9] Electrical on-board network (1) according to claim 7 or 8, characterized by , that the further DC voltage converter (11) coupled to the third sub-system (12) is coupled with its input to the high-voltage system (8).

Images