On-board electrical system for a vehicle, and vehicle

Abstract

The invention discloses an on-board electrical system (1) for a vehicle, comprising: - a first on-board electrical system portion (2), - a second on-board electrical system portion (3), - at least a third on-board electrical system portion (4), and - a DC-isolating coupling unit (5), wherein the first on-board electrical system portion (2), the second on-board electrical system portion (3) and the third on-board electrical system portion (4) are each connected to the coupling unit (5), wherein the coupling unit (5) is designed to inductively transmit electrical voltage of an on-board electrical system portion (2, 3, 4) to at least one of the other on-board electrical system portions (2, 3, 4) via a coupling element (5a). The invention also discloses a vehicle comprising an on-board electrical system (1) of this kind.

Description

[0001] DESCRIPTION

[0002] On-board network for a vehicle and vehicle

[0003] The present invention relates to an on-board network for a vehicle and to a vehicle.

[0004] Electrically powered vehicles have an on-board electrical system with different voltage levels, with individual consumers and energy storage devices being connected to one of these voltage levels. Such a vehicle may have a fuel cell and / or an electrical energy storage device, with an electric drive motor being able to be fed with the power from this to drive the vehicle. A section of the on-board electrical system with which the fuel cell or energy storage device is connected is usually referred to as a high-voltage on-board electrical system. Typical voltage levels are above 400 V, particularly in the range between 400 and 1200 V, although development also aims to achieve even higher voltage levels. Another section, which is connected to consumers or energy storage devices that require a lower voltage level, can be referred to as a low-voltage on-board electrical system.Typical voltage levels in the commercial vehicle sector are 12 to 48 V. Consumers located in the low-voltage electrical system can also perform safety-critical functions of the vehicle, particularly in automated ferry operations, which requires a fail-safe design of the vehicle's electrical system. At the same time, it is necessary to provide uninterrupted power to components of an electrical system if their primary power supply fails.

[0005] This requires electrical and electronic components such as voltage converters that can transfer electrical voltages and power between the individual vehicle electrical system sections, which leads to an increase in the number of electronic components as the number of vehicle electrical system sections increases.

[0006] It is therefore an object of the present invention to provide an on-board electrical system for a vehicle that features a reduction in the number of these components. This object is achieved by the subject matter of the independent claims.

[0007] Advantageous further training is the subject of the subclaims.

[0008] According to the invention, an electrical system for a vehicle is provided. The electrical system has a first electrical system section, a second electrical system section, at least one third electrical system section, and a galvanically isolating coupling unit. The first electrical system section, the second electrical system section, and the third electrical system section are each connected to the coupling unit, wherein the coupling unit is designed to inductively transmit electrical voltage from one electrical system section to at least one of the other electrical system sections via a coupling element. The coupling unit is preferably designed to convert the inductively transmitted voltage.

[0009] The voltage of the individual vehicle electrical system sections is applied to the respective electrical inputs of the coupling unit. Thus, the voltage of the first vehicle electrical system section is applied to the input to which the first vehicle electrical system section is connected. Accordingly, the voltage of the second vehicle electrical system section is applied to the input to which the second vehicle electrical system section is connected, and the voltage of the third vehicle electrical system section is applied to the input to which the third vehicle electrical system section is connected.

[0010] The galvanically isolating coupling unit prevents direct transmission of electrical current from one electrical system section to another. The electrical system sections, which operate at different voltage levels in particular, are thus protected from each other.

[0011] In this way, voltage conversion or voltage transmission can take place between individual vehicle electrical system sections, whereby only one component, namely the coupling unit, is required. Thus, electrical power can also be transmitted from one vehicle electrical system section to one or more of the other vehicle electrical system sections. Preferably, the coupling unit is designed such that a magnetic flux passing through the coupling element can be influenced by interaction with the first vehicle electrical system section, the second vehicle electrical system section, and the third vehicle electrical system section. In particular, it can also be provided that further vehicle electrical system sections, such as the further vehicle electrical system section described below, are designed to influence the magnetic flux. The vehicle electrical system sections can be connected via the connections.

[0012] The transfer of electrical power from one section of the vehicle electrical system to another is thus achieved by manipulating the magnetic flux.

[0013] In order to interact with the magnetic flux accordingly, the coupling unit preferably has a coil between the respective connection to one of the vehicle electrical system sections and the coupling element, with the coupling element extending through the coil. The coils thus make it possible to adjust the voltage according to the transformer principle based on their number of turns. If a first voltage Ui is applied to the coil with the number of turns Ni, which is connected to the connection connected to the first vehicle electrical system section, this generates a magnetic flux in the coupling element. This flux also flows through a second coil with the number of turns N2, which is connected to the connection connected to the second vehicle electrical system section. The ratio of the number of turns then results in the voltage U2, which is applied to the connection connected to the second vehicle electrical system section:

[0014] Ü2 = N2 / N1 X Ü1

[0015] A voltage U3 applied to the terminal connected to the third electrical system section is then given by the number of turns N3 of the coil connected to this terminal:

[0016] U3 = N3 / N1 x Ui The coupling unit can thus have or provide different voltages at the individual terminals with which it is connected to the individual vehicle electrical system sections. In particular, the second vehicle electrical system section can have a voltage level of 12 to 48 V, preferably 24 to 48 V, and / or the third vehicle electrical system section can have a voltage level of 12 to 48 V, preferably 12 to 24 V. The first vehicle electrical system section is then preferably designed as a high-voltage vehicle electrical system section.

[0017] The coupling element preferably consists of a ferromagnetic material or preferably comprises a ferromagnetic material. This facilitates the propagation and guidance of the magnetic flux within the coupling element, and in particular toward the aforementioned coils. Furthermore, stray magnetic flux is reduced. The ferromagnetic material used includes, for example, iron, cobalt, and / or nickel.

[0018] The coupling unit preferably has voltage rectifying elements designed to rectify the electrical voltage applied to the respective connection of the coupling unit by the first vehicle electrical system section, the second vehicle electrical system section, or the third vehicle electrical system section, such that the respectively rectified voltage is applied to the respective inductive coupling with the coupling element. The magnetic flux within the coupling element is then influenced by this rectified voltage. Furthermore, a voltage applied to the inductive coupling by an induced magnetic flux can also be rectified by the voltage rectifying element connected to the inductive coupling, so that a voltage type is present that is required by the vehicle electrical system section connected there.

[0019] Preferably, a voltage rectifying element comprises a bridge circuit configured to convert an applied DC voltage into an AC voltage, which is then applied to the inductive coupling, by appropriately controlling switches, in particular transistors, of the bridge circuit. Alternatively or additionally, the coupling unit comprises voltage conversion elements configured to convert the electrical voltage applied to the coupling unit by the first vehicle electrical system section, the second vehicle electrical system section, or the third vehicle electrical system section, so that the respectively converted voltage is applied to the respective inductive coupling with the coupling element.

[0020] Preferably, the first electrical system section includes an energy storage device. Consumers connected to the first electrical system section can be supplied from the energy storage device. However, power can also be supplied to the energy storage device. This is the case, for example, when a generator-driven electrical machine provides corresponding power within the first electrical system section.

[0021] Alternatively or additionally, the second electrical system section includes an energy storage device. Consumers connected to the second electrical system section can be supplied from the energy storage device. However, power can also be supplied to the energy storage device. This is the case, for example, when power is supplied from another electrical system section, in particular from the first electrical system section, to the second electrical system section via the coupling unit.

[0022] Individual energy storage units can be dimensioned with smaller capacities. This is because the electrical system section in which this energy storage unit is located can be supplied by another electrical system section via the coupling unit.

[0023] For example, generative power from an electric drive motor can be transferred from a high-voltage on-board network section to the individual energy storage unit.

[0024] The coupling unit is preferably designed to transmit power from one vehicle electrical system section to at least one other vehicle electrical system section. This is the case, for example, if an energy storage device or another energy source designed to supply the corresponding vehicle electrical system section with power has failed or is empty. The power supply can then be ensured via the coupling unit, which then makes power available to another vehicle electrical system section. For example, the first vehicle electrical system section can supply the second and / or third vehicle electrical system section, or vice versa. The coupling unit thus allows a bidirectional supply. This applies in particular to the supply from high-voltage to low-voltage vehicle electrical system sections and vice versa.

[0025] According to a preferred embodiment, the vehicle electrical system is designed such that only one or more energy storage devices are present, located in high-voltage vehicle electrical system sections. Thus, in this case, the low-voltage vehicle electrical system sections are supplied by transferring voltage or power from these high-voltage vehicle electrical system sections to the low-voltage sections via the coupling unit. This advantageously eliminates the need for energy storage devices on the low-voltage side or in the low-voltage vehicle electrical system sections.

[0026] Preferably, a line connection is provided between at least two on-board network sections, via which line connection a power and / or voltage can be transmitted between the on-board network sections. This line connection serves for power and / or voltage transmission while bypassing the coupling unit. In this way, one on-board network section can supply another on-board network section. This supply can be provided in the normal state, i.e. that one on-board network section is always supplied by another on-board network section. In particular, it can be provided that a on-board network section which is always supplied by another on-board network section does not have its own energy storage device. Furthermore, it can be provided that a redundant supply of the on-board network section in question is provided via this line connection. i.e. that the supply of the on-board network section in question can be provided via the line connection if the actually intended supply oranother supply to this on-board network section has failed. If the on-board network sections connected by the cable connection have different voltage levels, voltage converters can be provided to equalize the voltage. The on-board network sections connected via the cable connection are preferably high-voltage or low-voltage on-board network sections. Preferably, the first on-board network section is designed as a high-voltage on-board network section and the second on-board network section is designed as a low-voltage on-board network section. The voltage level at which the high-voltage on-board network section is operated can then be above 400 V and in particular between 400 and 1200 V. Voltage levels above 1200 V are also possible. The low-voltage on-board network section has a voltage that is in particular between 12 and 48 V, preferably 24 V.

[0027] In this configuration, in which the first vehicle electrical system section is designed as a high-voltage vehicle electrical system section and the second vehicle electrical system section is designed as a low-voltage vehicle electrical system section, it is preferably possible to transmit power from the first vehicle electrical system section to the second vehicle electrical system section via the coupling unit. This enables a redundant supply to at least one consumer that is connected to the second vehicle electrical system section. The vehicle electrical system is then preferably designed such that safety-critical elements that operate in the low-voltage range represent consumers of the second vehicle electrical system section. If the power supply to the second vehicle electrical system section fails, for example because the energy storage device in the second vehicle electrical system section is empty or defective, these consumers can still be supplied by the first vehicle electrical system section via the coupling unit.This allows for a redundant power supply, particularly in automated vehicles, while simultaneously reducing the complexity and number of components. The invention thus represents a way to secure the power supply of components used for HAD Level 4 or 5. Thus, a power failure of the second on-board power supply section does not automatically require a driver to intervene to control the vehicle. Rather, the functionality of these components can be maintained, since power can be supplied, for example, by the first on-board power supply section via the coupling unit.

[0028] The second vehicle electrical system section or the coupling unit preferably has a connection via which an electrical voltage can be applied from an external device in order to supply the second vehicle electrical system section with voltage. This can be an external voltage source which, for example, makes it possible to recharge an energy storage device in the second vehicle electrical system section. Furthermore, it can also be provided that the coupling unit also supplies the first vehicle electrical system section with voltage based on the voltage applied to this connection. In this way, an energy storage device which is provided in the first vehicle electrical system section can also be supplied with voltage and charged. The external voltage source can in particular be a vehicle battery of another vehicle. This usually has a low voltage.However, a voltage source such as a charger or wall box can also be provided to charge the vehicle's energy storage devices via this connection.

[0029] In general, the first electrical system section can be supplied from the second electrical system section, particularly if it is designed as a high-voltage electrical system section, with the supply being provided via the coupling unit. Thus, the supply can be provided both from the first electrical system section to the second electrical system section and vice versa. The coupling unit thus allows bidirectional supply.

[0030] Preferably, the third electrical system section does not have an energy storage device. Instead, the third electrical system section is supplied with voltage by the first electrical system section and / or the second electrical system section. The voltage can be supplied via the coupling unit if the voltage of the third electrical system section differs from that of the first electrical system section and / or that of the second electrical system section. Instead, the voltage can also be supplied directly if the voltage levels are the same. Supply via the coupling unit eliminates the need for additional voltage converters, which would otherwise have to be provided between the electrical system sections.

[0031] Preferably, at least one additional electrical system section is provided, which is connected to the coupling unit. This additional electrical system section can have a voltage level that corresponds to or differs from that of the previously mentioned electrical system sections. In particular, it can be provided that the additional electrical system section is a high-voltage electrical system section. Preferably, a configuration is then provided in which the first electrical system section is designed as a high-voltage electrical system section and the second and third electrical system sections are designed as low-voltage electrical system sections.

[0032] According to a preferred embodiment, the coupling unit is designed as a multiple active bridge converter. Preferably, the first and at least one further electrical system sections are designed as high-voltage electrical system sections, while the second and third electrical system sections are designed as low-voltage electrical system sections.

[0033] As mentioned above, a line connection can be provided between at least two on-board network sections, via which power and / or voltage can be transmitted between the on-board network sections. This line connection serves for power and / or voltage transmission without the coupling unit. In this way, one on-board network section can supply another on-board network section. This supply can be provided in the normal state, i.e. that one on-board network section is always supplied by another on-board network section. In particular, it can be provided that a on-board network section that is always supplied by another on-board network section does not have its own energy storage device. If the on-board network sections connected by the line connection have different voltage levels, voltage converters can be provided to equalize the voltage.

[0034] The on-board electrical system or the coupling unit preferably has at least one control unit designed to control the coupling unit such that a voltage or energy supply can be provided to the on-board electrical system sections connected to the coupling unit. In particular, the voltage rectifying elements and / or the voltage converting elements are controlled in this case. The control unit is advantageously designed to monitor individual consumers, energy storage devices or other components of the individual on-board electrical system sections and to react to component failures or to the charge states of energy storage devices and to control the coupling unit accordingly. A second coupling unit is preferably provided, wherein at least two on-board electrical system sections of the first on-board electrical system section, the second on-board electrical system section and the third on-board electrical system section are connected to the second coupling unit.In this way, these vehicle electrical system sections can be mutually supplied with power via either the first or the second coupling unit. This increases redundancy within the vehicle electrical system. Particularly preferably, the first vehicle electrical system section and the second vehicle electrical system section are connected to the second coupling unit.

[0035] The above describes an on-board electrical system for a vehicle, wherein the transmission of voltage or power between individual on-board electrical system sections is carried out by a single coupling unit. The coupling element can preferably be designed as an integral component that has connections for the individual on-board electrical system sections and that contains the coupling element. Furthermore, the coupling unit can also have the control unit described above and the voltage rectifying elements described above. Particularly preferably, the coupling unit has a housing to accommodate these elements.

[0036] The vehicle electrical system is preferably designed to balance the charge of the energy storage devices of the individual vehicle electrical system sections or of individual energy storage devices of individual vehicle electrical system sections. For example, balancing can be achieved via the coupling unit by transferring power from an energy storage device in one vehicle electrical system section to an energy storage device in another vehicle electrical system section. This can be done particularly when the different vehicle electrical system sections are subject to different loads from their consumers. In this way, balancing operation of the energy storage devices or individual energy storage devices is possible.

[0037] According to the invention, a vehicle with an on-board power system as described above is provided, wherein the vehicle is preferably designed as a battery-electric vehicle or as a fuel cell vehicle. The invention is described below using preferred embodiments with the aid of the accompanying drawings.

[0038] It shows

[0039] Fig. 1a an embodiment of the invention,

[0040] Fig. 1 b shows a structure of a coupling unit from Fig. 1 a,

[0041] Fig. 2a shows a further development of the embodiment of Fig. 1a, and

[0042] Fig. 2b shows a structure of the coupling unit from Fig. 2a.

[0043] Fig. 1a shows an embodiment of the invention.

[0044] A vehicle electrical system 1 is shown.

[0045] The vehicle electrical system 1 has a first electrical system section 2, which is designed as a high-voltage electrical system section. The first electrical system section 2 has a high-voltage storage unit 2a, high-voltage consumers 2b, and an electric drive 2c. The high-voltage consumers 2b and drive 2c are connected to the high-voltage storage unit 2a via a fuse box 2d. The first electrical system section 2 is connected to a coupling unit 5 via the fuse box 2d.

[0046] The vehicle electrical system 1 has a second electrical system section 3, which is designed as a low-voltage electrical system section. The second electrical system section 3 has a low-voltage storage unit 3a and low-voltage consumers 3b, with the low-voltage consumers 3b being connected to the low-voltage storage unit 3a. The second electrical system section 3 is also connected to the coupling unit 5.

[0047] The vehicle electrical system 1 has a third vehicle electrical system section 4, which is designed as a low-voltage vehicle electrical system section. The third vehicle electrical system section 4 has low-voltage consumers 4b. Optionally, a low-voltage storage unit 4a can also be provided, with the low-voltage consumers 4b being connected to the low-voltage storage unit 4a. The third vehicle electrical system section 4 is likewise connected to the coupling unit 5. However, as shown, it is also possible for the third vehicle electrical system section 4 to be supplied by the first or second vehicle electrical system section 2, 3, either by using a direct line connection 7 (see below). However, it is also possible for the third vehicle electrical system section 4 to be supplied by the supplying first vehicle electrical system section 2, wherein in this case the supply is provided via the intermediate coupling unit 5 in order to equalize the voltages.

[0048] The line connection 7 exists between the third vehicle electrical system section 4 and the second vehicle electrical system section 3. This connects the low-voltage storage unit 4a of the third vehicle electrical system section 4 to consumers 3b of the second vehicle electrical system section 3. The line connection 7 can connect all or only some of the consumers 3b of the second vehicle electrical system section 3 to the third vehicle electrical system section 4. The safety-critical consumers among the consumers 3b of the second vehicle electrical system section 3 are preferably connected to the third vehicle electrical system section 4 via the line connection 7. In this way, a redundant supply from the low-voltage storage unit 4a of the third vehicle electrical system section 4 can be achieved.

[0049] Furthermore, the second vehicle electrical system section 3 has a terminal 3e to which electrical voltage can be applied from an external device 8 as described above.

[0050] For a more detailed description of the coupling unit 5, please refer to Fig. 1b.

[0051] The coupling unit 5 is shown enlarged here. It essentially has a coupling element 5a, which is designed here as an iron core and is indicated as such in the drawing. The terminals 5b of the coupling unit 5 are inductively coupled to the coupling element 5a, with each on-board electrical system section 2, 3, 4 being connected to a terminal 5b. The inductive coupling of the terminals 5b to the coupling element 5a is each realized by a coil through which the coupling element 5a extends. Thus, magnetic flux passing through the coupling element 5a can induce a voltage in the coils, or a coil can influence the magnetic flux by applying a corresponding voltage. Furthermore, the terminals 5b have voltage rectifying elements, which are designed, for example, as bridge circuits, in order to rectify the voltage accordingly, as described above.

[0052] The coupling unit 5 further comprises a further connection 5b, with which, as shown here, a connection to the first vehicle electrical system section 2 is established, thereby achieving redundancy in the connection between the coupling unit 5 and the first vehicle electrical system section 2. However, it can also be provided that additional vehicle electrical system sections are connected to the coupling unit 5.

[0053] As described above, a voltage supply to the vehicle electrical system sections 2, 3, and 4 can now be achieved via the coupling unit 5. For example, voltage or power from the first vehicle electrical system section 2 can be converted via the coupling unit 5 and made available to the vehicle electrical system sections 3, 4. Voltage or power from the second vehicle electrical system section 3 can also be converted via the coupling unit 5 and made available to the vehicle electrical system sections 2, 4.

[0054] Fig. 2a shows a further development of the embodiment from Fig. 1a.

[0055] The coupling unit 5 is supplemented here by a further or second coupling unit 6, whereby the remaining structure of the vehicle electrical system 1 corresponds to that shown in Fig. 1a. Therefore, reference is made to the above description. The second coupling unit 6 enables a second supply path for individual vehicle electrical system sections 2, 3, 4 if the first coupling unit 5 fails.

[0056] Fig. 2b now shows a possible connection of the further or second coupling unit 6. The coupling unit 6 corresponds in its structure and function to the coupling unit 5 described above, wherein the first on-board electrical system section 2, the second on-board electrical system section 3, and the third on-board electrical system section 4 are connected in the same way to the further coupling unit 6 via its connections 6b. The further coupling unit 6 can thus be used to increase redundancy. For this purpose, it is connected in parallel to the coupling unit 5. Alternatively or in addition to the second connection of the second on-board electrical system section 2, at least one further on-board electrical system section can also be connected to the coupling units 5 and 6.

[0057] LIST OF REFERENCE SYMBOLS

[0058] 1 on-board network

[0059] 2 first on-board network section

[0060] 2a high-voltage storage

[0061] 2b High-voltage consumers

[0062] 2c electric drive

[0063] 2d fuse box

[0064] 3 second electrical system section

[0065] 3a Low-voltage storage

[0066] 3b Low-voltage consumers

[0067] 3rd connection

[0068] 4 third electrical system section

[0069] 4a Low-voltage storage

[0070] 4b Low-voltage consumers

[0071] 5 Coupling unit

[0072] 5a Coupling element

[0073] 5b connection

[0074] 6 second coupling unit

[0075] 6a Coupling element

[0076] 6b connection

[0077] 7 Line connection

[0078] 8 external device

Claims

PATENT CLAIMS 1 . Electrical system (1 ) for a vehicle, comprising: - a first on-board network section (2), - a second on-board network section (3), - at least a third on-board network section (4), and - a galvanically isolating coupling unit (5), wherein the first on-board network section (2), the second on-board network section (3) and the third on-board network section (4) are each connected to the coupling unit (5), wherein the coupling unit (5) is designed to inductively transmit electrical voltage from an on-board network section (2, 3, 4) to at least one of the other on-board network sections (2, 3, 4) via a coupling element (5a).

2. On-board network (1) according to claim 1, wherein the coupling unit (5) is designed such that a magnetic flux passing through the coupling element (5a) can be influenced in interaction with the first on-board network section (2), the second on-board network section (3) and the third on-board network section (4).

3. On-board network (1) according to one of the preceding claims, wherein the coupling element (5a) consists of a ferromagnetic material or comprises a ferromagnetic material.

4. On-board network (1) according to one of the preceding claims, wherein the coupling unit (5) has voltage conversion elements and / or voltage rectifying elements which are designed to convert and / or rectify the electrical voltage which is applied to the coupling unit (5) through the first on-board network section (2), the second on-board network section (3) or the third on-board network section (4), so that the respectively converted and / or rectified voltage is applied to the respective inductive coupling with the coupling element (5a).

5. On-board network (1) according to one of the preceding claims, wherein the first on-board network section (2) has an energy store (2a) and / or wherein the second on-board network section (3) has an energy store (3a).

6. On-board network (1) according to one of the preceding claims, wherein the coupling unit (5) is designed to supply power from an on-board network section (2, 3, 4) to at least one other on-board network section (2, 3, 4).

7. On-board network (1) according to one of the preceding claims, wherein a line connection (7) is provided between at least two on-board network sections (3, 4), via which line connection a power and / or voltage transmission can take place between the on-board network sections (3, 4).

8. Vehicle electrical system (1) according to one of the preceding claims, wherein the first vehicle electrical system section (2) is designed as a high-voltage vehicle electrical system section and the second vehicle electrical system section (3) is designed as a low-voltage vehicle electrical system section.

9. On-board network (1) according to claim 8, wherein Power can be transmitted from the first on-board network section (2) to the second on-board network section (3) via the coupling unit (5), thereby enabling a redundant supply of at least one consumer connected to the second on-board network section (3).

10. On-board network (1) according to claim 8 or 9, wherein the second on-board network section (3) or the coupling unit (5) has a connection via which an electrical voltage can be applied from an external device (8) in order to supply the second on-board network section (3) with voltage.

11. On-board network (1) according to one of the preceding claims, wherein the third on-board network section (4) has no energy storage device and is instead supplied with voltage by the first on-board network section (2) and / or the second on-board network section (3).

12. On-board network (1) according to one of the preceding claims, wherein at least one further on-board network section is provided which is connected to the coupling unit (5).

13. On-board network (1) according to one of the preceding claims, wherein the on-board network (1) or the coupling unit (5) has at least one control unit which is designed to control the coupling unit (5) in such a way that a voltage or energy supply to the on-board network sections (2, 3, 4) connected to the coupling unit (5) can take place.

14. On-board network (1) according to one of the preceding claims, wherein a second coupling unit (6) is provided and at least two on-board network sections of the first on-board network section (2), the second on-board network section (3) and the third on-board network section (4) are connected to the second coupling unit (6).

15. Vehicle with an on-board network (1) according to one of claims 1 to 14.

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