On-board electrical system for an at least partially electrically operated motor vehicle, motor vehicle and method for operating an on-board electrical system

Abstract

The invention relates to an on-board electrical system (14) for an at least partially electrically operated motor vehicle (10) comprising a high voltage network (16), a link circuit network (18) and a low voltage network (20), wherein the low voltage network (20) is supplied with electrical energy from the high voltage network (16) via the link circuit network (18), wherein the high voltage network (16) has a first safety circuit (28) and the link circuit network (18) has a second safety circuit (32), wherein the first safety circuit (28) is designed to interrupt an energy supply to the link circuit network (18) in the event of a first overvoltage in the link circuit network (18), and wherein the second safety circuit (32) is designed to interrupt an energy supply to the low voltage network (20) in the event of a second overvoltage, different than the first overvoltage, in the low voltage network (20). The invention furthermore relates to a motor vehicle (10) and to a method for operating the on-board electrical system (14).

Description

[0001] 23-2454 PIF

[0002] 1

[0003] Electrical system for a motor vehicle that is at least partially electrically powered, motor vehicle and method for operating an electrical system

[0004] The following invention relates to an electrical system for a motor vehicle that is at least partially electrically powered, comprising a high-voltage network, an intermediate circuit network, and a low-voltage network, wherein the low-voltage network is supplied with electrical energy from the high-voltage network via the intermediate circuit network according to claim 1. Furthermore, the invention relates to a motor vehicle and a method for operating a high-voltage network.

[0005] It is already known from automotive engineering that vehicles can be operated at least partially or fully automatically in the future. Furthermore, vehicles can be at least partially or fully electric. In particular, this requires that parts of the actuator system also be electrified. This applies to both the control and power components. This entails high availability and increased power consumption. The obvious primary solution is to power the control units, electronic computing devices, and actuators with voltage converters from a traction battery, which in this case is primarily a high-voltage battery and / or operates in the low-voltage range. A key objective is to make these voltage converters ever smaller, cheaper, more efficient, and, above all, safer.

[0006] DC-DC converters come in countless designs. The first main group is the galvanically isolated type using transformers. However, these are too expensive, too large, and require a correspondingly large amount of copper for the coils; furthermore, many switches are necessary. The second group consists of boost / bubble converters. These are available in unidirectional and bidirectional versions. In these converters, a coil is typically charged for a specific time via a switch and discharged again by opening and / or closing the charging circuit, for example, via a switch or a diode. Another special type of non-galvanically isolated converter is the charge pump using primary capacitors. 23-2454 PIF

[0007] 2

[0008] A fundamental technical problem is that buck converters, unlike DC / DC converters with a transformer, do not offer galvanic isolation. This often prevents their use, as a simple fault can lead to voltage transfer from the supply network. Consequently, all low-voltage loads would have to be designed to draw power from the supply network, which is particularly complex in high-voltage conversion systems. This simple fault can occur due to a fault in the control circuit or a material defect in the switching element. Therefore, the cost, efficiency, and space advantages of buck converters have not yet been fully exploited according to current technological standards.

[0009] DE 102022 130 515 A1 discloses embodiments of a power converter comprising a power conversion circuit and a protection circuit. The power conversion circuit is electrically coupled between a first terminal and a second terminal to convert a first voltage from the first terminal into a second voltage output at the second terminal. The protection circuit is electrically coupled between an input terminal of the power converter and the first terminal. The protection circuit includes a first protection device and a clamping circuit. The first protection device withstands an input voltage of the power converter to allow the power conversion circuit to continue operating when the input voltage exceeds a voltage threshold. The clamping circuit is electrically coupled to a control terminal of the first protection device to clamp a control voltage of the first protection device.

[0010] CN 11549 787 A relates to a voltage regulation circuit and an electronic device. The voltage regulation circuit comprises a first power supply; the input end of the boost module is connected to the first power supply; the input end of the buck module is connected to the output end of the boost module, and the output end of the buck module is used to supply voltage to an electrical load; the output end of the timing control module is connected to both the boost module and the buck module; and the protection circuit is connected to the first power supply, and the protection circuit is used to protect the boost module when the timing control module is switched off.According to the voltage regulation circuit, the protection circuit is arranged to protect the boost module when the sequential control module is switched off, so that damage to any part of the boost module's switching device due to the switching off of the sequential 23-2454 PIF.

[0011] Control module is avoided, normal operation of the voltage regulation circuit is ensured, and the operational reliability of the voltage regulation circuit is improved.

[0012] The object of the present invention is to create an electrical on-board network, a motor vehicle and a method by which an improved operation of an at least partially electrically operated motor vehicle can be realized.

[0013] This problem is solved by an electrical electrical system, a motor vehicle, and a method according to the independent claims. Advantageous embodiments are specified in the dependent claims.

[0014] One aspect of the invention relates to an electrical on-board network for a motor vehicle that is at least partially electrically operated, comprising a high-voltage network, an intermediate circuit network and a low-voltage network, wherein the low-voltage network is supplied with electrical energy from the high-voltage network via the intermediate circuit network.

[0015] It is provided that the high-voltage network has a first safety circuit and the intermediate circuit network has a second safety circuit, wherein the first safety circuit is designed to interrupt the power supply to the intermediate circuit network in the event of a first overvoltage in the intermediate circuit network, and wherein the second safety circuit is designed to interrupt the power supply to the low-voltage network in the event of a second overvoltage in the low-voltage network that differs from the first overvoltage.

[0016] In particular, this makes it possible to provide a correspondingly improved electrical system and thus achieve improved operation of the vehicle.

[0017] In particular, a stepped buck converter with safety circuits is provided, whereby the safety circuits can act very quickly and purely on a hardware basis on the corresponding switches. The tripping mechanism is, in particular, an overvoltage in the DC link or the low-voltage circuit. Overall, this results in at least double protection through multiple voltage levels, which also improves the dynamics, and a stepped safety shutdown concept. This is achieved by incorporating several independent 23-2454 PIFs.

[0018] 4

[0019] Safety mechanisms increase the overall safety of the system accordingly, as the dangerous residual error probabilities no longer add up.

[0020] For example, the high-voltage network can be available at 400 volts and, for instance, stepped down to 100 volts for the intermediate circuit using a first buck converter. The intermediate circuit can then, in turn, step down from 100 volts to 48 volts for the low-voltage electrical system. These configurations are purely exemplary and serve only to illustrate the invention. Other voltage levels are, of course, also possible in the high-voltage network, the intermediate circuit network, and the low-voltage network.

[0021] According to an advantageous embodiment, the first and second safety circuits are interconnected and configured to trigger both when one is triggered. For example, if a fault is detected in the DC link network, the first safety circuit can trigger and simultaneously trigger the second. Similarly, if a fault occurs in the low-voltage network, the second safety circuit can trigger and simultaneously trigger the first. This offers the particular advantage of ensuring double safety. In other words, the

[0022] The safety circuits are designed in such a way that they act on each other's buck converters, thus ensuring double protection. This allows for improved operation of the vehicle's electrical system.

[0023] Another advantageous configuration involves the high-voltage network having a first buck converter and the DC link network having a second buck converter. This allows for galvanic isolation between the high-voltage and low-voltage networks without the need for expensive and heavy DC / DC converters with transformer components. In particular, this prevents the low-voltage loads from also being designed to operate on the supply network, i.e., the high-voltage network. This offers significant cost, efficiency, and space advantages. Alternatively, the high-voltage network can have a first charge pump and the DC link network a second charge pump.

[0024] It is further advantageous if the first safety circuit and / or the second safety circuit have a respective overvoltage pass-through component (see 23-2454 PIF).

[0025] 5

[0026] Switching of a specific switching element within the respective safety circuit. In particular, the overvoltage can be mitigated via a surge-passive component, such as a reverse-biased diode, a spark gap, or similar device, and thus act on a voltage divider. This, in turn, triggers an electronic switching element that pulls the control signal of the corresponding main switch of the safety device to zero, thereby opening it. In this way, a simple safety circuit can be provided.

[0027] It has also proven advantageous if the first safety circuit and / or the second safety circuit each have a comparator circuit for switching a respective switching element of the respective safety circuit. In particular, the safety circuit can thus be implemented via a comparator circuit, which represents a very simple design.

[0028] It is also advantageous if the first safety circuit is mounted on a first heat sink and the second safety circuit is mounted on a second heat sink. In particular, the first heat sink is then separate from the second. Alternatively, different cooling systems can be provided instead of heat sinks; these can be active or passive cooling systems. This prevents a common fault source, thus enabling improved operation of the electrical system.

[0029] In a further advantageous embodiment, the first safety circuit is provided for in a first housing and the second safety circuit is provided for in a second housing. In particular, the first housing is separate from the second housing. Thus, the two safety circuits are housed in separate enclosures, which can, in particular, serve as fire barriers. This allows for improved operation of the electrical system.

[0030] It is also advantageous if the enclosures are designed as EMC enclosures. EMC refers specifically to electromagnetic compatibility. In particular, the enclosures offer appropriate EMC protection, for example, by being made of sheet metal. This allows for improved operation of the electrical system. 23-2454 PIF

[0031] 6

[0032] Another aspect of the invention relates to a motor vehicle with at least one electrical system as described in the preceding aspect. The motor vehicle is specifically designed as an at least partially electrically powered vehicle or as a fully electric vehicle. Furthermore, the motor vehicle can be designed as an at least partially automated vehicle or as a fully automated vehicle.

[0033] A further aspect of the invention relates to a method for operating an electrical on-board network according to the preceding aspect. This involves detecting a first overvoltage in the intermediate circuit network and triggering at least the first safety device, and / or detecting a second overvoltage in the low-voltage network and triggering at least the second safety circuit.

[0034] Advantageous designs of the electrical system are to be regarded as advantageous designs of the motor vehicle and the process. The electrical system and the motor vehicle possess tangible features to enable the corresponding process steps to be carried out.

[0035] Further features of the invention will become apparent from the claims, the figures, and the description of the figures. The features and combinations of features mentioned above in the description, as well as the features and combinations of features mentioned below in the description of the figures and / or shown in the figures alone, are not only usable in the combinations specified, but also in other combinations or on their own.

[0036] The invention will now be explained in more detail with reference to a preferred embodiment and the drawings. The drawings show:

[0037] Fig. 1 a schematic side view of an embodiment of a

[0038] motor vehicle with an embodiment of an electrical on-board network; and

[0039] Fig. 2 shows a schematic block diagram according to one embodiment of an electrical vehicle electrical system. 23-2454 PIF

[0040] 7

[0041] In the figures, identical or functionally equivalent elements are provided with the same reference symbols.

[0042] Fig. 1 shows a schematic side view of an embodiment of a motor vehicle 10. The motor vehicle 10 is, in particular, at least partially or fully electrically powered. Furthermore, the motor vehicle 10 can also be at least partially or fully automatically operated. For this purpose, the motor vehicle 10 has an electrical energy storage device 12, which is, in particular, designed as a high-voltage energy storage device and can, for example, have a voltage of 400 volts. The motor vehicle 10 also has an electrical system 14. The electrical system 14 has at least a high-voltage network 16, an intermediate circuit network 18, and a low-voltage network 20. Electrical consumers 22, for example, can be connected to the low-voltage network 20.

[0043] Fig. 2 shows a schematic block diagram of an embodiment of the electrical on-board network 14. In particular, the high-voltage network 16, the intermediate circuit network 18 and the low-voltage network 20 with a low-voltage consumer 22 are shown.

[0044] The high-voltage network 16 has input terminals 24, which can be connected, for example, to the electrical energy storage device 12. In the present embodiment, the high-voltage network 16 has a first buck converter 26 and a first safety circuit 28. The intermediate circuit network 18 has a second buck converter 30 and a second safety circuit 32. For example, the first buck converter 26 can be configured to reduce a voltage from 400 volts to 100 volts. The second buck converter 30, in turn, is configured to reduce the voltage from 100 volts to, for example, 48 volts for the low-voltage network 20.

[0045] The first buck converter 26, for example, has at least two first transistors 34. Furthermore, the first buck converter 26 has two switching elements 36. The first buck converter 26 also has two capacitors 38 and one inductor 40.

[0046] The second buck converter 30 also has, for example, two first transistors 34, two switching elements 36, two capacitors 38 and an inductor 40.

[0047] The first transistors 34 in the first buck converter 26 and in the second buck converter 30 can, for example, be essentially designed as MOSFETs. 23-2454 PIF

[0048] In the low-voltage network 20, the electrical load 22 is, for example, designed as a motor. In the present embodiment, the low-voltage network 20 includes, in particular, further transistors 54, two DC / DC converters 42, and, for example, an electronic computing unit 44.

[0049] In the present embodiment, the first safety circuit 28 comprises three resistors 46, a second transistor 52 and an overvoltage forwarding component 48, for example in the form of a diode.

[0050] The second safety circuit 32 is essentially similar in construction and also has three resistors 46, a second transistor 34 and an overvoltage pass-through component 48.

[0051] Overall, the figures show the electrical on-board network 14 with at least the high-voltage network 16, the intermediate circuit network 18 and the low-voltage network 20. The low-voltage network 20 is supplied with electrical energy from the high-voltage network 16 via the intermediate circuit network 18.

[0052] It is provided that the high-voltage network 16 has the first safety circuit 28 and the intermediate circuit network 18 has the second safety circuit 32, wherein the first safety circuit 28 is designed to interrupt a power supply to the intermediate circuit network 18 in the event of a first overvoltage, and wherein the second safety circuit 32 is designed to interrupt a power supply to the low-voltage network 20 in the event of a second overvoltage that differs from the first overvoltage.

[0053] It is specifically provided that the first safety circuit 28 and the second safety circuit 32 are interconnected and that the safety circuits 28, 32 are configured to trigger the other safety circuit 28, 32 when one of the safety circuits 28, 32 is triggered. This is shown here by means of a respective interconnection circuit 50.

[0054] Furthermore, Fig. 2 shows in particular that the high-voltage network 16 can have the first buck converter 26 and the intermediate circuit network 18 can have the second buck converter 30. 23-2454 PIF

[0055] 9

[0056] Furthermore, Fig. 2 shows that the first safety circuit 28 and / or the second safety circuit 32 each have a respective overvoltage pass-through component 48 for switching a respective switching element of the respective safety circuit 28, 32.

[0057] Alternatively, the first safety circuit 28 and / or the second safety circuit 32 can each have a comparator circuit for switching a respective switching element of the respective safety circuit 28, 32.

[0058] Furthermore, it can be provided that the first safety circuit 28 is mounted on a first heat sink and the second safety circuit 32 is mounted on a second heat sink. The heat sinks are specifically designed separately from each other. It can also be provided that the first safety circuit 28 is mounted in a first housing and the second safety circuit 32 is mounted in a second housing. The housings can specifically be designed separately from each other. In addition, it can be provided that the housings are designed as EMC housings.

[0059] In particular, a stepped buck converter with safety circuits 28 and 32 is provided, whereby the safety circuits 28 and 32 act very quickly and purely hardware-based on the corresponding main switches. The tripping mechanism is an overvoltage either in the DC link network 18 or in the low-voltage network 20, whereby the safety switches can act on the other buck converter 26 and 30 in a correspondingly nested arrangement. Thus, double protection is ensured.

[0060] In total, this results in more than double the protection provided by multiple voltage levels, which also improves the dynamics and a staged safety shutdown concept. By incorporating several independent safety mechanisms, the overall safety of the electrical system is increased, as the dangerous residual fault probabilities no longer add up. -2454 PIF

[0061] Reference symbol list

[0062] motor vehicle electrical energy storage electrical system

[0063] High-voltage network

[0064] Intermediate circuit network

[0065] Low-voltage network of electrical consumers

[0066] Connection terminals first buck converter first safety circuit second buck converter second safety circuit first transistor

[0067] Switching element

[0068] capacity

[0069] Inductance

[0070] DC / DC converter electronic computing device

[0071] Resistance

[0072] Overvoltage pass-through component

[0073] Entanglement circuit second transistor further transistor

Claims

23-2454 PIF 11 Patent claims 1. Electrical system (14) for a motor vehicle (10) that is at least partially electrically powered, comprising a high-voltage network (16), an intermediate circuit network (18), and a low-voltage network (20), wherein the low-voltage network (20) is supplied with electrical energy from the high-voltage network (16) via the intermediate circuit network (18), characterized in that the high-voltage network (16) has a first safety circuit (28) and the intermediate circuit network (18) has a second safety circuit (32), wherein the first safety circuit (28) is configured to interrupt the power supply to the intermediate circuit network (18) in the event of a first overvoltage in the intermediate circuit network (18), and wherein the second safety circuit (32) is configured to interrupt the power supply to the low-voltage network (20) in the event of a second overvoltage in the low-voltage network (20) that differs from the first overvoltage.

2. Electrical on-board network (14) according to claim 1, characterized in that the first safety circuit (28) and the second safety circuit (32) are designed to be intertwined and the safety circuits (28, 32) are designed to trigger the other safety circuit (28, 32) when one of the safety circuits (28, 32) is triggered.

3. Electrical system (14) according to claim 1 or 2, characterized in that the high-voltage system (16) has a first buck converter (26) and the intermediate circuit system (18) has a second buck converter (30) or the high-voltage system (16) has a first charge pump and the intermediate circuit system (18) has a second charge pump.

4. Electrical on-board network (14) according to one of the preceding claims, characterized in that 23-2454 PIF 12 the first safety circuit (28) and / or the second safety circuit (32) each have a respective overvoltage pass-through component (48) for switching a respective switching element of the respective safety circuit (28, 32).

5. Electrical on-board network (14) according to one of the preceding claims, characterized in that the first safety circuit (28) and / or the second safety circuit (32) each have a comparator circuit for switching a respective switching element of the respective safety circuit (38, 32).

6. Electrical on-board network (14) according to one of the preceding claims, characterized in that the first safety circuit (28) is formed on a first heat sink and the second safety circuit (32) is formed on a second heat sink.

7. Electrical on-board network (14) according to one of the preceding claims, characterized in that the first safety circuit (28) is formed in a first housing and the second safety circuit (32) is formed in a second housing.

8. Electrical on-board network (14) according to claim 7, characterized in that the housings are designed as EMC housings.

9. Motor vehicle (10) with at least one electrical on-board network (14) according to one of claims 1 to 8.

10. Method for operating an electrical on-board network (14) according to one of claims 1 to 8, comprising the steps: Detection of an initial overvoltage in the intermediate circuit network (18) and triggering of at least the first safety device (28); and / or Detection of a second overvoltage in the low-voltage network (20) and triggering at least the second safety circuit (32).

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