Electrical system for a vehicle

Abstract

The invention relates to an electrical system (1) for a vehicle with - a first sub-network (2), - a second sub-network (3) which is electrically connected or switchable in parallel with the first sub-network (2) and - a DC-DC converter (4) which is electrically coupled with its output to the first sub-vehicle network (2). According to the invention - a safety separating element (5) is arranged between the first sub-vehicle network (2) and the second sub-vehicle network (3), which in a first state electrically connects the first and second sub-vehicle networks (2, 3) and in a second state electrically separates the first and second sub-vehicle networks (2, 3) from each other, and - an electrical energy storage device (9) is arranged in the second sub-vehicle network (3).

Description

[0001] The invention relates to an electrical system for a vehicle according to the preamble of claim 1.

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

[0003] Furthermore, an on-board power supply system for a vehicle is known from DE 10 2022 001 268 A1. The on-board power supply system comprises a primary power supply system and a primary battery, with two or more low-voltage power supplies connected to the primary power supply system via respective DC-DC converters. The low-voltage power supplies each have one or more low-voltage consumers, with one of the low-voltage power supplies having its own low-voltage battery. The primary power supply system is configured as a high-voltage power supply system, and the primary battery is configured as a high-voltage battery. Furthermore, a switch is provided for selectively disconnecting the primary battery from the primary power supply system or connecting the primary battery to the primary power supply system.

[0004] The present invention is based on the object of providing a novel electrical system for a vehicle.

[0005] The object is achieved 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 has a first sub-system, a second sub-system that is electrically connected or switchable in parallel with 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 sub-vehicle electrical system and the second sub-vehicle electrical system. This element electrically connects the first and second sub-vehicle electrical systems in a first state and electrically disconnects the first and second sub-vehicle electrical systems in a second state. An electrical energy storage device is arranged in the second sub-vehicle electrical system.

[0009] The present electrical system enables electrical isolation of the first and second sub-systems in the event of a fault, thanks to the electrical connection switchable by means of the safety isolating element. The energy storage device in the second sub-system allows for independent supply of electrical loads in the sub-systems in such a fault. This allows compliance with so-called "Automotive Safety Integrity Levels" (ASIL for short). Furthermore, continuous charging of the energy storage device is possible in the first state of the safety isolating element—that is, when the two sub-systems are electrically connected.

[0010] Furthermore, the safety isolating element and the energy storage device mean that no separate DC-DC converter is required to supply the second sub-system, resulting in weight, cost, and installation space advantages. At the same time, no separate energy storage device is required to operate the first sub-system, which also results in weight, cost, and installation space advantages. The first sub-system can be electrically supplied by the DC-DC converter, which is designed to be particularly highly dynamic and highly available. Due to the coupling with the second sub-system, the energy storage device present there nevertheless provides an intelligent mechanism for shortening the start-up times of electrical consumers, such as electrical control units, in the first sub-system without an energy storage device.

[0011] Furthermore, the design of the on-board electrical system with the safety isolating element and the energy storage device allows the number of semiconductor switches for power distribution to be minimized, resulting in cost and complexity advantages. Each power distributor can also be designed with fuses, subject to special load arrangements and the safety isolating element.

[0012] According to one possible design of the on-board electrical system, the first sub-system and the second sub-system are configured to provide a redundant electrical supply for electrical consumers that are safety-relevant for the operation of the vehicle. This enables a secure power supply for electrical consumers with redundancy requirements, so that high ASIL requirements can be met. Homogeneous redundancy, for example, providing an energy storage device for each sub-system, can be avoided, since the energy storage device of the second sub-system serves as the safety energy source and the directly coupled DC-DC converter serves as the safety energy source. This avoids dependent faults, in particular so-called "common-cause faults" and so-called "cascading faults."

[0013] According to a further possible embodiment of the electrical system, it has a third sub-system and a further DC-DC converter, the output of which is electrically coupled to the third sub-system. For example, the third sub-system is designed to supply electrical loads intended for comfort functions. This design achieves a separation between the safety-relevant electrical loads present in the first sub-system and the second sub-system and the electrical loads intended for comfort functions. This, in turn, means that the further DC-DC converter coupled to the third sub-system and the electrical loads present in the third sub-system do not have to meet high safety or availability requirements, which results in cost and complexity reductions.This eliminates the need for complex safety mechanisms, which, according to VDA 450, must be implemented in a mixed on-board network channel, i.e., a sub-network with electrical consumers related to comfort functions and safety-relevant electrical consumers. The possible separation of the electrical supply for safety and comfort functions can also reduce the load on the energy storage system in the second sub-network, as the separation results in a significantly lower "worst-case load" for this energy storage system, as defined by VDA 450. Furthermore, the separation ensures that the third sub-network is free from interference with the first and second sub-networks.

[0014] According to a further possible embodiment of the electrical system, an electrical energy storage device is arranged in the third sub-system, which allows for continued electrical supply to the electrical consumers present in the third sub-system even if the third sub-system is disconnected from a power supply. Due to the possible separation from the first and second sub-systems and the energy storage device present in the second sub-system, the energy storage device advantageously does not have to meet stringent safety or availability requirements.

[0015] According to a further possible embodiment of the electrical system, a coupling element is arranged between the third sub-system and the first sub-system, which in a first state electrically connects the third and first sub-systems and in a second state electrically disconnects the third and first sub-systems. Such a separation enables a reduction in the energy requirements of the energy storage device in the third sub-system, since high demands on the energy content of the energy storage device, for example, due to ensuring 60 minutes of hazard warning flashing after a crash, can be taken over 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 precharging of the DC-DC converter coupled to the first sub-vehicle electrical system through the use of power-controlled mechanisms, in that energy is fed from the energy storage device of the third sub-vehicle electrical system to the DC-DC converter via the coupling element. Energy efficiency can also be increased because the DC-DC converter coupled to the first sub-vehicle electrical system can be used for certain processes instead of the DC-DC converter coupled to the third sub-vehicle electrical system. This is particularly the case when the DC-DC converter coupled to the first sub-vehicle electrical system is directly coupled to a high-voltage electrical energy storage device of a high-voltage electrical system, since this direct coupling eliminates the need to supply current to 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 embodiment of the electrical system, it comprises a high-voltage electrical system that is or can be coupled to at least one high-voltage electrical energy storage device. The high-voltage electrical system enables the vehicle's electrical consumers to be supplied with power in the high-voltage range.

[0017] According to another possible embodiment of the electrical system, the DC-DC converter coupled to the first sub-system is connected via its input to the high-voltage energy storage device. Such a direct connection of the first and second sub-systems to the high-voltage energy storage device increases the availability of the supply to the electrical consumers in both sub-systems. Furthermore, due to this direct connection, shutting down the first and second sub-systems is not necessary after a vehicle crash, especially if the high-voltage energy storage device is disconnected from the high-voltage electrical system by a switching element.

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

[0019] According to a further possible embodiment of the on-board electrical system, it has a control unit which is designed at least to control the safety isolating element. The control unit can also be designed to control the coupling element. In particular, the control unit is further designed to receive crash signals and error signals detected by an on-board sensor system, for example signals relating to electrical faults in the on-board electrical system, and, if such signals are present, to control the safety isolating element and / or the coupling element in such a way that the sub-on-board electrical systems can be electrically separated / isolated from one another. In a further possible embodiment of the on-board electrical system, the safety isolating element and / or the coupling element are designed as mechanical switches, as electromagnetic relays, or as semiconductor switches.

[0020] According to a further possible embodiment of the electrical system, the coupling element and / or the safety isolating element are designed as a fuse or semiconductor fuse and are triggered automatically if the current flow is too high.

[0021] According to another possible embodiment of the electrical system, it can comprise additional sub-systems that can be separated from or coupled to one another using safety isolating elements and / or coupling elements. This creates a modular and scalable architecture that can be easily adapted, for example, to different vehicle configurations with different electrical convenience and / or safety consumers. This allows the complexity of the electrical system to be adapted and minimized to specific requirements.

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

[0023] Showing: Fig. 1 schematically shows an embodiment of an on-board network of a vehicle, Fig. 2 schematically shows another embodiment of an on-board network of a vehicle, Fig. 3 schematically shows another embodiment of an on-board network of a vehicle, Fig. 4 schematically shows another embodiment of an on-board network of a vehicle, Fig. 5 schematically shows another embodiment of an on-board network of a vehicle and Fig. 6 schematically shows another embodiment of an on-board network of a vehicle.

[0024] Corresponding parts are provided with the same reference numerals in all figures.

[0025] In Fig. Figure 1 shows a possible embodiment of a vehicle's 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 isolating element 5.

[0026] The two sub-vehicle electrical systems 2, 3 are designed, in particular, as low-voltage electrical systems and are intended to provide a redundant electrical supply to the same electrical consumers 6.1 to 6.n. A nominal voltage of the sub-vehicle electrical systems 2, 3 is, for example, 12 volts. In particular, the sub-vehicle electrical systems 2, 3 are safety electrical systems, which are designed to provide a redundant electrical supply to electrical consumers 6.1 to 6.n that are safety-relevant for the operation of the vehicle. The electrical consumers 6.1 to 6.n are designed, for example, to operate a steering system, a brake, lighting, automated driving functions of the vehicle, etc. For example, the electrical consumers 6.1 to 6.n are control units. In a manner not shown in detail, both sub-vehicle electrical systems 2, 3 each comprise a plurality of power distributors with semiconductor fuses for connecting the electrical consumers 6.1 to 6.n to the respective sub-vehicle electrical system 2, 3.Instead of power distributors with semiconductor fuses, fuses can also be used, depending on an existing safety concept.

[0027] The DC-DC converter 4 is coupled to an energy source on the input side in a manner not shown in detail and converts a source voltage into a lower low voltage for the two sub-vehicle networks 2, 3. The energy source is, for example, a Fig. 2 to 6, and / or a high-voltage energy storage device 7 shown in more detail in Fig. 2 to 6 show the high-voltage electrical system 8 in more detail.

[0028] On the output side, the DC-DC converter 4, which is particularly designed to be highly dynamic and highly available, is electrically coupled to the first sub-vehicle electrical system 2 and supplies it with electrical power. In particular, the DC-DC converter 4 is designed to supply all static and dynamic electrical loads in the first sub-vehicle electrical system 2.

[0029] The safety isolating element 5 is arranged between the first sub-vehicle electrical system 2 and the second sub-vehicle electrical system 3 and, in a first state, electrically connects the first and second sub-vehicle electrical systems 2, 3 to one another, so that the second sub-vehicle electrical system 3 is also electrically coupled to the output of the DC-DC converter 4. This enables a bidirectional current flow between the sub-vehicle electrical systems 2, 3.

[0030] An electrical energy storage device 9 is arranged in the second sub-vehicle electrical system 3. This electrical energy storage device is electrically charged in the first state of the safety isolating element 5 and is thus highly available. In particular, the energy storage device 9 is designed to supply all static and dynamic electrical loads in the second sub-vehicle electrical system 3.

[0031] In a second state, the safety isolating element 5 electrically separates the first and second sub-vehicle electrical systems 2, 3 from one another. The safety isolating element 5 is switched to the second state, for example, when voltage and / or current values ​​are undershot or exceeded, or when the energy source coupled to the DC-DC converter 4 fails, for example due to an electrical fault or a disconnection of the energy source from the DC-DC converter 4. The energy source is disconnected from the DC-DC converter 4, for example, after a vehicle crash if the energy source is designed as a high-voltage energy storage device 7 or high-voltage vehicle electrical system 8, in order to prevent the application of high voltage, which could be life-threatening, to body parts of the vehicle, as well as electrical faults and resulting damage to the vehicle and its surroundings.

[0032] In one possible embodiment, the DC-DC converter 4 is directly coupled to the energy source embodied 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, so that both sub-vehicle electrical systems 2, 3 can advantageously continue to be supplied with electrical energy in the event of faults in the high-voltage vehicle electrical system 8. This results in an increased availability of the sub-vehicle electrical systems 2, 3 and the loads 6.1 to 6.n arranged therein.

[0033] For automatic control of the safety separation element 5, a control unit (not shown in detail) is provided. For example, the control unit is designed to receive crash signals and error signals detected by the vehicle's own sensors, for example, signals relating to electrical faults in the vehicle electrical system 1, and, if such signals are present, to control the safety separation element 5 in such a way that the sub-vehicle electrical systems 2, 3 can be electrically separated / disconnected from one another.

[0034] Due to the electrical energy storage device 9 present in the second sub-vehicle network 3, the electrical supply to the consumers 6.1 to 6.n can be ensured even if the two sub-vehicle networks 2, 3 are separated / disconnected.

[0035] 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 decoupled from the high-voltage electrical system 8 via a switching element 10.

[0036] 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. The DC-DC converter 11 is provided 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.

[0037] The third sub-system 12 is designed, for example, as a comfort system for supplying electrical loads 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-system 12 can also supply other electrical loads 13.1 to 13.m not intended for comfort functions.

[0038] In a manner not shown in detail, the third sub-vehicle network 12 comprises several power distributors with fuses or semiconductor fuses for connecting the electrical consumers 13.1 to 13.m to the third sub-vehicle network 12.

[0039] Furthermore, an electrical energy storage device 14 is arranged in the third sub-vehicle network 12, which is electrically charged by the DC-DC converter 11. In particular, the energy storage device 14, when the DC-DC converter 11 is deactivated, is designed to supply all dynamic electrical loads, i.e., dynamic processes and functional states, in the third sub-vehicle network 12.

[0040] The illustrated embodiment of the on-board network 1 represents a first module of a scalable or modular on-board network structure, which is designed depending on various vehicle features, equipment and / or safety requirements of the vehicle.

[0041] In the illustrated embodiment of the on-board electrical system 1, the third sub-network 12, designed as a low-voltage on-board electrical system, meets only low safety requirements without redundancy requirements. An on-board electrical system 1 designed in this way is used, for example, in a lightweight and small vehicle without redundancy requirements for electrical systems and with maximum safety requirements up to "Automotive Safety Integrity Level" B (abbreviated to "ASIL" B).

[0042] In Fig. 3 shows another possible embodiment of an on-board network 1 of a vehicle. Based on the Fig. 2, this comprises, in addition to the third sub-network 12, as a further module the Fig. 1 and designed according to the associated description, which is electrically coupled to the high-voltage energy storage device 7 via the DC-DC converter 4 and, when the switching element 10 is closed, to the high-voltage vehicle electrical system 8.

[0043] 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.

[0044] In the illustrated embodiment of the on-board network 1, the separation of the two sub-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 without redundancy requirements. An on-board network 1 configured in this way is used, for example, in a heavy vehicle without redundancy requirements for electrical systems and maximum safety requirements up to "Automotive Safety Integrity Level" C (abbreviated to "ASIL" C).

[0045] Fig. 4 shows another possible embodiment of an on-board network 1 of a vehicle. Based on the Fig. 3, this comprises, in addition to the first and third sub-networks 2, 12, as a further module the Fig. 1 and designed according to the associated description, which can be coupled to or decoupled from the first sub-network 2 via the safety separation element 5.

[0046] The third sub-vehicle network 12 is designed, for example, as a pure comfort vehicle network, wherein the first and second sub-vehicle networks 2, 3 are designed as pure safety vehicle networks and for the redundant supply of the same safety-relevant electrical consumers 6.1 to 6.n.

[0047] In the illustrated embodiment of the on-board network 1, the separation of the first and second sub-networks 2, 3 from the third sub-network 12 as well as 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. An on-board network 1 configured in this way is used, for example, in a heavy vehicle with redundancy requirements for electrical systems and maximum safety requirements extending up to "Automotive Safety Integrity Level" D (abbreviated to "ASIL" D).

[0048] Furthermore, due to the separation of the first and second sub-vehicle networks 2, 3 from the third sub-vehicle network 12, the third sub-vehicle network 12 can be supplemented as desired with further electrical consumers 13.1 to 13.m without the need to adapt the dimensioning of the energy storage device 9 present in the second sub-vehicle network 3.

[0049] In Fig. 5 shows another possible embodiment of an on-board network 1 of a vehicle. In addition to the Fig. In the exemplary embodiment illustrated in Figure 3, a coupling element 15 is arranged between the third sub-vehicle electrical system 12 and the first sub-vehicle electrical system 2. In a first state, this coupling element 15 electrically connects the third and first sub-vehicle electrical systems 12, 2 to one another and, in a second state, electrically disconnects the third and first sub-vehicle electrical systems 12, 2. For automatic control of the coupling element 15, the control unit also provided for controlling the safety separation element 5 or a further control unit (not shown in detail) is used.

[0050] Opening the coupling element 15 enables a reduction in energy demands on the energy storage device 14 in the third sub-vehicle network 12, since high demands on the energy content of the energy storage device 14, for example, due to ensuring 60 minutes of hazard warning flashing after a crash, can be taken over by the highly available DC-DC converter 4 of the first sub-vehicle network 2. Since this converter is directly coupled to the high-voltage energy storage device 7, no shutdown is required after a crash.

[0051] Furthermore, pre-charging of the DC-DC converter 4 is simplified by supplying energy from the energy storage device 14 of the third sub-vehicle network 12 to the DC-DC converter 4 via the closed coupling element 15.

[0052] In addition, an increase in energy efficiency can be achieved because the DC-DC converter 4 can be used for certain processes instead of the DC-DC converter 11. The direct connection of the DC-DC converter 4 to the high-voltage energy storage unit 7 eliminates the need to supply power to the entire high-voltage vehicle electrical system 8.

[0053] Fig. 6 shows a further possible embodiment of an on-board network 1 of a vehicle. Based on the Fig. 5, this comprises, in addition to the first and third sub-networks 2, 12, as a further module the Fig. 1 and designed according to the associated description, which can be coupled to or decoupled from the first sub-network 2 via the safety separation element 5.

[0054] In addition to the benefits of the Fig.5, the direct connection of the DC-DC converter 4 to the high-voltage energy storage device 7 and the resulting elimination of the current supply to the entire high-voltage vehicle electrical system 8 can, for example, enable energy-efficient recharging of the energy storage device 9 in the second sub-vehicle electrical system 3 when the vehicle is parked. List of reference symbols 1 on-board network 2 first sub-wiring system 3 second sub-network 4 DC-DC converters 5 Safety separator 6.1 to 6.n Consumers 7 high-voltage energy storage units 8 High-voltage electrical system 9 Energy storage 10 Switching element 11 DC-DC converters 12 third sub-wiring system 13.1 to 13.m consumers 14 energy storage 15 coupling element QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2018 214 759 A1

[0002] DE 10 2022 001 268 A1

[0003]

Claims

[1] Electrical system (1) for a vehicle with - a first sub-network (2), - a second sub-network (3) which is electrically connected or switchable in parallel with the first sub-network (2) and - a DC-DC converter (4) which is electrically coupled with its output to the first sub-vehicle network (2), characterized by , that - a safety separating element (5) is arranged between the first sub-vehicle network (2) and the second sub-vehicle network (3), which in a first state electrically connects the first and second sub-vehicle networks (2, 3) and in a second state electrically separates the first and second sub-vehicle networks (2, 3) from each other, and - an electrical energy storage device (9) is arranged in the second sub-vehicle network (3). [2] Electrical system (1) according to claim 1, characterized bythat the first sub-vehicle network (2) and the second sub-vehicle network (3) are designed to provide a redundant electrical supply to electrical consumers (6.1 to 6.n) that are safety-relevant for the operation of the vehicle. [3] Electrical system (1) according to claim 1 or 2, characterized by - a third sub-network (12) and - a further DC-DC converter (11), which is electrically coupled with its output to the third sub-vehicle network (12). [4] Electrical system (1) according to claim 3, characterized by that a coupling element (15) is arranged between the third sub-vehicle network (12) and the first sub-vehicle network (2), which coupling element (15) electrically connects the third and first sub-vehicle networks (12, 2) to one another in a first state and electrically separates the third and first sub-vehicle networks (12, 2) from one another in a second state. [5] Electrical system (1) according to claim 3 or 4, characterized bythat an electrical energy store (14) is arranged in the third sub-vehicle network (12). [6] Electrical system (1) according to one of claims 3 to 5, characterized by that the third sub-vehicle network (12) is designed to provide electrical supply to electrical consumers (13.1 to 13.m) intended for comfort functions. [7] Electrical system (1) according to one of the preceding claims, characterized by a high-voltage vehicle electrical system (8) which is or can be coupled to at least one high-voltage electrical energy storage device (7). [8] Electrical system (1) according to claim 7, characterized by that the DC-DC converter (4) coupled to the first sub-vehicle network (2) is coupled with its input to the high-voltage electrical energy storage device (7). [9] Electrical system (1) according to claim 7 or 8, characterized bythat the further DC-DC converter (11) coupled to the third sub-vehicle network (12) is coupled with its input to the high-voltage vehicle network (8). [10] Electrical system (1) according to one of the preceding claims, characterized by a control unit which is designed at least to control the safety separation element (5).

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