On-board power system arrangement for a vehicle

Abstract

The invention relates to an on-board power supply system (10) for a vehicle (20), comprising a high-voltage battery (3) for providing energy at a high-voltage voltage, a DC / DC converter device (1) for converting the high-voltage voltage into at least one low-voltage voltage for supplying at least one low-voltage on-board power supply system (6, 7) with a plurality of electrical consumers (4, 5), including at least one safety-critical consumer (4) and at least one non-safety-critical consumer (5), and an energy management system (11), wherein a first low-voltage on-board power supply system (6) and a second low-voltage on-board power supply system (7) are provided, wherein the consumers (4, 5) are connected to the first low-voltage on-board power supply system (6), wherein the second low-voltage on-board power supply system (7) is connected to the first low-voltage on-board power supply system (6) via a coupling element (8) which is closed during normal operation and can thus be selectively connected to or disconnected from the first low-voltage on-board power supply system (6).wherein the at least one safety-critical consumer (4) is also redundantly connected to the second low-voltage vehicle electrical system (7), wherein a low-voltage battery (9) is further connected to the second low-voltage vehicle electrical system (7), wherein the energy management system (11) is configured to open the coupling element (8) in the event of failure of the DC / DC converter device (1) and / or in the event of failure of the second low-voltage vehicle electrical system (7), in particular of the low-voltage battery (9).

Description

The invention relates to an on-board power supply system arrangement for a vehicle according to the preamble of claim 1, an electrically driven vehicle according to the preamble of claim 3 and a method for operating the on-board power supply system arrangement according to the preamble of claim 5.Known vehicle electrical system arrangements for vehicles having a high-voltage vehicle electrical system and two redundant low-voltage vehicle electrical systems require two DC / DC converters for the safe supply of safety-relevant loads.DE 10 2017 216 739 A1 describes a vehicle electrical system which is equipped with a first vehicle electrical system branch and a second vehicle electrical system branch and with a DC / DC converter which connects these vehicle electrical system branches and has a first side and a second side. The first side is connected to the first on-board power system branch and the second side is connected to the second on-board power system branch. In the first on-board power system branch, the second on-board power system branch or in both on-board power system branches, an electrically operated component having a first actuator and a second actuator redundant thereto is provided, both of which act on the same element of the component. The first actuator is directly connected to the DC / DC converter. The second actuator is connected to the DC / DC converter via a controllable isolating switch device.The invention is based on the object of specifying a novel on-board power supply system arrangement for a vehicle, a novel vehicle and a novel method for operating the on-board power supply system arrangement.The object is achieved according to the invention by an on-board power supply system arrangement for a vehicle having the features of claim 1, an electrically driven vehicle having the features of claim 3 and a method for operating the on-board power supply system arrangement having the features of claim 5.Advantageous embodiments of the invention are the subject matter of the dependent claims.An on-board power supply system arrangement for a vehicle is proposed, comprising a high-voltage battery for providing energy with a high-voltage, a DC / DC converter device for converting the high-voltage into at least one low-voltage voltage for supplying at least one low-voltage on-board power supply system with a plurality of electrical loads, including at least one safety-critical load and at least one non-safety-critical load, and an energy management system. According to the invention, a first low-voltage on-board power supply system and a second low-voltage on-board power supply system are provided, wherein the consumers are connected to the first low-voltage on-board power supply system, wherein the second low-voltage on-board power supply system is connected to the first low-voltage on-board power supply system via a coupling element which is closed in a closed-loop control mode and can therefore be selectively connected to it or disconnected from it. The at least one safety-critical load is redundantly also connected to the second low-voltage on-board power supply system, but not to the non-safety-critical loads. A low-voltage battery is furthermore connected to the second low-voltage on-board power supply, wherein the energy management system is configured to open the coupling element in the event of failure of the DC / DC converter device and / or in the event of failure of the second low-voltage on-board power supply, in particular of the low-voltage battery.According to the present invention, the non-safety-critical consumers are switched off in the event of a failure of the DC / DC converter device or of one of the low-voltage on-board power supply systems.By switching off the non-safety-critical consumers in the event of a fault, the safety-critical consumers can be supplied redundantly.In this case, only one DC / DC converter device is required for operating two redundant low-voltage on-board power supply systems. This reduces the installation space requirement and the costs.The DC / DC converter device advantageously has a plurality of DC / DC converters with a summed converter power which is sufficient to supply all connected loads.According to one aspect of the present invention, an electrically driven vehicle having the above-described on-board power supply system is proposed, wherein the high-voltage battery is configured to supply power to an electric machine for driving the vehicle.In one specific embodiment, the at least one safety-critical load includes a brake system and / or a steering system of the vehicle and / or an advanced driver assistance system. The advanced driver assistance system, also known briefly as ADAS, is a driver assistance system having electronic additional devices in motor vehicles for assisting the driver in certain driving situations. Safety aspects play an important role here above all in planning, guiding and stabilizing a driving task, but are also otherwise always important in the driver assistance systems.Exemplary embodiments of the invention are explained in more detail below with reference to drawings.The following are shown: FIG. 1 shows a schematic view of an on-board power supply system having a DC / DC converter device, and FIG. 2 is a schematic view of an electrically driven vehicleCorresponding parts are provided with the same reference numerals in all figures.FIG. 1 is a schematic view of an on-board power system arrangement 10 having a DC / DC converter device 1, in which a high-voltage from a high-voltage battery 3 is converted by the DC / DC converter device 1 into at least one low-voltage voltage for supplying a first low-voltage on-board power system 6 and a second low-voltage on-board power system 7. Electrical loads 4, 5, including safety-critical load 4 and non-safety-critical load 5, are connected to the first low-voltage on-board power supply 6. The second low-voltage on-board power supply system 7 is connected to the first low-voltage on-board power supply system 6 via a coupling element 8, for example a relay, a contactor or a semiconductor circuit, and can therefore be selectively connected to the latter or disconnected therefrom. The safety-critical consumers 4 are redundantly also connected to the second low-voltage on-board power supply system 7, but not the non-safety-critical consumers 5.An energy management system 11 is provided for controlling and / or regulating the coupling element 8.The DC / DC converter device 1 can have a DC / DC converter or a plurality of DC / DC converters 2.1 to 2.n, so-called rails. The DC / DC converters 2.1 to 2.n are referred to as rails, since they are frequently electrically connected by means of busbars. However, electrical interconnection by means of cables is also possible. The DC / DC converters 2.1 to 2.n serve to ensure high energy availability for supplying the safety-critical loads 4.To fulfil these safety goals, four DC / DC converters 2.1 to 2.4, for example, each having a power of 1.5 kW, for example, i.e. a summed power of 6 kW, are arranged in the DC / DC converter device 1 in FIG. 1.This summed power (in the present example 6 kW) is available for all consumers 4, 5, i.e. also the non-safety-critical consumers 5.From the functional safety perspective, a part of the DC / DC converters 2.1 to 2.4, for example, of the DC / DC converter 2.1, serves as redundancy. In order to fulfil the safety goals, only the power of the remaining DC / DC converters 2.2 to 2.4 is thus available.The safety-critical consumers 4 require high energy availability. Therefore, the low-voltage on-board power supply systems 6, 7 are designed to be redundant.The redundant DC / DC converters 2.1 to 2.n are used in the regulating mode for the non-safety-critical loads 5. In the event of failure of one of the DC / DC converters 2.1 to 2.n, the loads 5 which are not critical for safety can be disconnected from the energy management system 11.The low-voltage battery 9 serves for stabilizing the vehicle electrical system in the regulating mode and for supplying the safety-critical consumers 4 in the event of a fault. The energy management system 11 is configured to open the coupling element 8 in the event of a fault in one of the low-voltage on-board electrical systems 6, 7 or the DC / DC converter device 1.It is advantageous here that only one DC / DC converter device 1 is required for operating two redundant low-voltage on-board electrical systems 6, 7. This reduces the installation space requirement and the costs.In the regulating mode, the coupling element 8 is closed. The DC / DC converter device 1 and the low-voltage battery 9 thus supply both low-voltage on-board electrical systems 6, 7 and the connected safety-critical consumers 4 and non-safety-critical consumers 5.In the event of a fault, for example in the event of failure of the DC / DC converter device 1 or of one or more of the DC / DC converters 2.1 to 2.n, the coupling element 8 is opened by the energy management system 11 and the two low-voltage on-board power supply systems 6, 7 are thus disconnected. The first low-voltage on-board power supply system 6 and the non-safety-critical loads 5 connected only there are thus no longer supplied with voltage and are out of operation. The second low-voltage on-board power supply system 7 and the safety-critical loads 4 redundantly connected there are supplied from the low-voltage battery 9.In a further fault case, for example in the event of failure of the second low-voltage on-board power supply 7, in particular of the low-voltage battery 9, the coupling element 8 is opened by the energy management system 11 and the two low-voltage on-board power supplies 6, 7 are thus disconnected. The second low-voltage on-board power supply system 7 is therefore no longer supplied with voltage and is out of operation. The first low-voltage on-board power supply system 6 and the safety-critical loads 4 redundantly connected there and, if appropriate, the non-safety-critical loads 5 connected there are supplied from the high-voltage battery 3 via the DC / DC converter device 1.Safety-critical consumers 4 can be, for example, a brake system and / or a steering system of a vehicle 20. Non-safety-critical consumers 5 can comprise, for example, entertainment electronics, interior lighting and air conditioning of the vehicle 20.FIG. 2 is a schematic view of an electrically powered vehicle 20 that may be equipped with the above-described onboard electrical system arrangement 10. The vehicle 20 may be, for example, a passenger car, a commercial vehicle or bus.The present invention provides a solution in which two redundant low-voltage on-board electrical systems 6, 7 are provided on the low-voltage side of the DC / DC converter device 1, which can be connected to one another via a coupling element 8. In the normal case, the coupling element 8 is closed. Thus, both low-voltage on-board power supply systems 6, 7 are supplied from the high-voltage battery 3 via the DC / DC converter device 1, and the low-voltage battery 9 is / is charged and / or stabilizes the low-voltage on-board power supply systems 6, 7.List of reference characters1 DC / DC converter device 2.1 to 2.n DC / DC converter 3 high-voltage battery 4 consumers, safety-critical consumer 5 consumers, non-safety-critical consumer 6 first low-voltage on-board power supply system 7 second low-voltage on-board power supply system 8 coupling element 9 low-voltage battery 10 on-board power supply system arrangement 11 energy management system 20 vehicleReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 10 2017 216 739 A1

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Claims

An on-board power supply system (10) for a vehicle (20), comprising a high-voltage battery (3) for providing energy with a high-voltage, a DC / DC converter device (1) for converting the high-voltage into at least one low-voltage for supplying at least one low-voltage on-board power supply system (6, 7) with a plurality of electrical loads (4, 5), including at least one safety-critical load (4) and at least one non-safety-critical load (5), and an energy management system (11), characterized in that a first low-voltage on-board power supply system (6) and a second low-voltage on-board power supply system (7) are provided, wherein the loads (4, 5) are connected to the first low-voltage on-board power supply system (6), wherein the second low-voltage on-board power supply system (7) is connected to the first low-voltage on-board power supply system (6) via a coupling element (8) which is closed in a control mode and is therefore optionally connectable to the latter or is separable therefrom, wherein the at least one safety-critical load (4) is redundantly also connected to the second low-voltage on-board power supply system (7), wherein a low-voltage battery (9) is furthermore connected to the second low-voltage on-board power supply system (7), wherein the energy management system (11) is configured to open the coupling element (8) in the event of failure of the DC / DC converter device (1) and / or in the event of failure of the second low-voltage on-board power supply system (7), in particular of the low-voltage battery (9).On-board power system arrangement (10) according to Claim 1, characterized in that the DC / DC converter device (1) has a plurality of DC / DC converters (2.1 to 2.n) with a summed converter power which is sufficient for supplying all connected loads (4, 5).Electrically driven vehicle (20) having an on-board power supply system arrangement (10) according to one of the preceding claims, characterized in that the high-voltage battery (3) is configured to supply power to an electric machine for driving the vehicle (20).Electrically driven vehicle (20) according to Claim 3, characterized in that the at least one safety-critical load (4) comprises a brake system and / or a steering system of the vehicle (20) and / or an advanced driver assistance system.Method for operating an on-board power supply system arrangement (10) according to Claim 1 or 2, characterized in that, in the event of failure of the DC / DC converter device (1) and / or in the event of failure of the second low-voltage on-board power supply system (7), in particular of the low-voltage battery (9), the coupling element (8) is opened by the energy management system (11).

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