DE102018218312A1 - Energy supply arrangement for supplying an electrical consumer of a low-voltage electrical system of a motor vehicle, electrical system and method for operating an energy supply arrangement - Google Patents

Abstract

The invention relates to an energy supply arrangement (13) with an output (40) for coupling to an electrical consumer (36), and a first and at least a second energy storage unit (B1, B2, B3, BN), which are connected in parallel to one another in a first operating state and provide a predetermined first supply voltage (U1) at the output (40). The energy supply arrangement (13) further comprises an input (38) for coupling to an energy source (32), a first switch unit (44) which, in a closed state, the first and the at least one second energy storage unit (B1, B2, B3, BN) couples in the first operating state to the input (38) and decouples in an open state from the input (38) in the second operating state, and a second switch unit (46) which, in the second operating state, the first and the at least one second energy storage unit (B1, B2, B3, BN) connects in series in order to provide a predetermined second larger supply voltage (U2) at the output (40) for supplying the electrical consumer (36).

Description

The invention relates to an energy supply arrangement for supplying at least one electrical consumer to a low-voltage electrical system of a motor vehicle, the energy supply arrangement having an output for coupling to the at least one electrical consumer, a first energy storage unit and at least a second energy storage unit, the first and the at least one second Energy storage units are connected in parallel in a first operating state and are designed to provide a predetermined first supply voltage at the output for supplying the at least one electrical consumer in the first operating state. The invention also includes an electrical system for a motor vehicle, and a method for operating an energy supply arrangement.

Various possibilities for interconnecting individual energy storage units of energy stores, such as batteries, are known from the prior art. For example, the DE 10 2015 010 531 A1 an electrical energy storage device and a battery management system used therein, which enable the setting of one or more variable supply voltages. In particular, the energy stores can also provide highly dynamically varying output voltages, for example in the form of alternating voltages. Furthermore describes the DE 10 2014 201 351 A1 an on-board electrical system with a low-voltage sub-network and a high-voltage sub-network with a starter generator. The high-voltage sub-network is connected to the low-voltage sub-network via a coupling unit. In addition, the vehicle electrical system has a battery that is set up to generate the high voltage and feed it into the high-voltage sub-network. Furthermore, this battery has at least two battery units with individual voltage taps, which are led to the coupling unit. It is provided that the coupling unit is set up to provide at least a first and a second operating state, wherein in the first operating state the high-voltage sub-network is fed from all battery units of the battery and the low-voltage sub-network is fed from a battery unit, and in a second operating state the high-voltage sub-network a battery unit is fed and the low-voltage sub-network is fed from at least one battery unit. The individual battery units can also be connected in parallel to feed the low-voltage sub-network. In particular, those battery units with a higher charge can be switched on in a targeted manner in order to enable charge equalization among the battery units.

Motor vehicle electrical systems typically have one or more defined voltage levels, such as a low voltage level at 12 volts and for example a high voltage level at 800 volts or also a medium voltage level at 48 volts. The consumers connected to these subnets are specifically designed for the relevant supply voltages. Furthermore, for example, the low-voltage electrical system can be fed from the high-voltage electrical system or the medium-voltage electrical system via a converter device, such as a DC / DC converter. This converter device then specifically converts the higher voltage level to the low voltage level. If the voltage level within such a sub-network, such as the low-voltage on-board network, were to be varied or designed to be variable, this would mean an adaptation of all possible consumers and, for example, also of the converter device. In order, for example, to be able to temporarily supply a consumer with higher power, special power-optimized energy storage devices, such as capacitors, are normally used, which can provide a very high current within a short time, as is also the case in, for example DE 10 2014 201 351 A1 is described.

The object of the present invention is to provide an energy supply arrangement, an on-board electrical system and a method for operating an energy supply arrangement, which allow more flexibility with regard to the energy supply of at least one electrical consumer of a low-voltage electrical system in the simplest possible way.

This object is achieved by an energy supply arrangement, by an on-board electrical system and by a method with the features according to the respective independent patent claims. Advantageous embodiments of the invention are the subject of the dependent claims, the description and the figures.

An energy supply arrangement according to the invention for supplying at least one electrical consumer of a low-voltage electrical system of a motor vehicle has an output for coupling to the at least one electrical consumer, a first energy storage unit and at least a second energy storage unit, the first and the at least one second energy storage unit in a first operating state are connected in parallel to one another and are designed to provide a predetermined first supply voltage at the output for supplying the at least one electrical consumer in the first operating state. In addition, the energy supply arrangement comprises an input for coupling to an energy source, a first switch unit is designed to couple the first and the at least one second energy storage unit to the input in a closed state and to decouple them from the input in an open state, the first switch unit being in the first operating state in the closed state and in a second operating state in the open state Condition. In addition, the energy supply arrangement comprises a second switch unit, which is designed to connect the first and the at least one second energy storage unit in series in the second operating state in order to supply a predetermined second supply voltage, which is greater than the first supply voltage, for supplying the at least one provide electrical consumer.

The invention advantageously makes it possible to use the first switch unit in the second operating state to decouple the energy supply arrangement from the rest of the energy network and to provide an increased supply voltage for the at least one electrical consumer at the output. The decoupling option advantageously means that no adaptations of other consumers or components of this energy network, such as a converter device as an energy source, are required. At the same time, it is possible to provide different supply voltages in different operating states specifically for at least one electrical component or an electrical consumer, which ultimately provides a particularly high degree of flexibility with regard to the energy supply of this consumer in a particularly simple and inexpensive manner. The invention is based on several findings: The highly automated driving enables new functions and offers for users in the future. In the future, it will be possible, even as a driver, to no longer devote yourself to the driving task and pursue other activities. New seat adjustment options are also possible during the journey, such as rotating the seat or adjusting the backrest angle to take a more comfortable sitting or lying position while driving. However, these considerations also result in new challenges. On the one hand, in the event of an accident, one would like to bring the driver and / or occupants into the best possible seating position in order to optimize the effect of the installed restraint systems. On the other hand, you want to quickly bring the driver back to the driving task in the event of certain errors in the vehicle. Both then require the seat position to be adjusted as quickly as possible. However, this is not easily possible with today's servomotors for seat adjustment, since studies show that the adjustment speeds are not sufficient for these cases. However, if the operating voltage is increased in today's servomotors, the possible powers and positioning speeds also increase. The invention now advantageously makes it possible, by means of the energy supply arrangement, to increase the supply voltage provided at the output, in particular by a multiple, which in turn increases the operating voltage of the motor for a short time for the at least one electrical consumer, such as a servomotor of an electrical seat adjustment device of a seat, and their control enables a multiple. In addition, this can be done in a particularly simple manner by means of a slight modification, for example of a redundant 12-volt battery, which must already be installed in today's concepts for highly automated driving in order to meet the high safety requirements. Especially in the case of low-voltage on-board electrical systems designed for highly automated driving, the invention can be implemented in a simple manner simply by providing a first and second switch unit, without any modifications having to be carried out on the remaining low-voltage on-board electrical system and the other consumers connected to it. Nonetheless, the idea described can also be used for functions other than seat adjustments and is not restricted solely to highly automated vehicles.

In the first operating state, the energy supply arrangement is preferably designed to provide a supply voltage at the output which corresponds to the voltage level defined for the low-voltage electrical system. This is currently 12 volts, but can generally be defined differently. The output of the energy supply arrangement can be provided, for example, by two output connections, one of which is connected to ground. Correspondingly, the input of the energy supply arrangement can also be provided by two input connections, one of which can also be grounded. In such a case, the first switch unit is designed to separate the two energy storage units from the input connection which is not grounded. In the first operating state, the at least two energy storage units are then connected in parallel both with respect to the output connections and with respect to the input connections, and in the second operating state the at least two energy storage units are connected in series with the two output connections and decoupled from the input.

The at least two energy storage units, that is to say the first and the at least one second energy storage unit, can each be a battery or a battery module or one or more battery cells, for example lithium-ion cells, and / or a capacitor or several capacitors or any Act combinations of these. However, more than just two energy storage units, for example three, four, five and so on, can also be provided. The supply voltage provided at the output in the second operating state always represents the total voltage of the individual voltages of the at least two energy storage units. If, for example, the energy supply arrangement comprises exactly two energy storage units in the form of two 12-volt batteries, in the second operating state a supply voltage of 24 volts is reached On the other hand, if the output is provided, the energy supply arrangement comprises three 12-volt batteries as energy storage units, a supply voltage of 36 volts is accordingly provided at the output in the second operating state, and so on.

It is particularly advantageous if the supply voltage that can be provided at the output in the second operating state is a maximum of 60 volts. The background is that the at least one electrical component or the at least one electrical consumer must also be designed accordingly for the higher supply voltage provided in the second operating state, but this requires hardly any or only minor structural changes, particularly in voltage ranges of less than 60 volts direct current.

Furthermore, the first switch unit is preferably designed as a bidirectional switch which enables blocking in both directions, that is to say both directions of current flow. For this purpose, the first switch unit can also have, for example, a plurality of individual switches, in particular electronically controllable switches, such as two MOSFETs (metal oxide semiconductor field effect transistors). The second switch unit can also comprise a plurality of individual switches, which can also each be designed as electronically controllable switches, in particular as semiconductor switching elements such as MOSFETs, for example.

In addition, the energy supply arrangement can have a control device for controlling the first switch unit and the second switch unit, as well as optional further switch units, for example a third switch unit or a further switch of the current limiting device explained in more detail later. This is designed to control the switches for implementing the first and second operating states, as well as transition phases accordingly.

If a higher voltage is now required for a short time by the at least one electrical consumer, the energy supply arrangement can advantageously be switched from the first operating state to the second operating state and thereby provide the higher supply voltage at the output. Subsequently, that is to say the increased supply voltage is no longer required by the at least one electrical consumer, it is possible to switch back from the second operating state to the first operating state. When switching from the second to the first operating state, however, it can happen that the at least two energy storage units now have a voltage different from the supply voltage to be coupled to the input energy source. If the energy storage units are, for example, batteries that are temporarily connected in series in order to supply the at least one electrical consumer with an increased supply voltage for a short time, these batteries are discharged in the meantime, since they are decoupled from the energy source by the first switch unit. The same applies to capacitors. A renewed connection to the energy source, that is to say when changing from the second to the first operating state, can accordingly result in high equalizing currents due to the high-current design of the battery system, which on the one hand could influence the energy network inadmissibly but could also damage the semiconductors.

It is therefore a further advantageous embodiment of the invention that the energy supply arrangement has a current limiting device which is designed to switch one from the energy source to the first during a transition from the second operating state to the first operating state in a state of the energy supply arrangement coupled via the input to the energy source and limit at least one second energy storage unit flowing compensation current or charging current. Thus, in the case of a large voltage difference between the voltage provided by the energy source and the voltage provided by the energy units, a negative influence on the energy network and possible damage to the semiconductors can be avoided. In the opposite case, that is to say if the voltage provided by the energy storage units should be greater than the voltage provided by the energy source, which can be the case due to feedback effects from the at least one electrical consumer, for example with a DC motor, this voltage difference can be determined reduce in a simple manner by supplying electrical loads coupled with the output of the energy supply arrangement, or possibly connecting further loads, until the differential voltage, i.e. the voltage between the respective energy storage units and the voltage provided by the energy source, reaches a minimum value, this means falls below a predetermined limit. The first switch unit can then be closed again and the energy supply arrangement can thereby be safely brought into the first operating state.

There are now advantageously several options for designing the current limiting device. In a particularly simple variant, the current limiting device can be designed as at least one electrical resistor arranged in series with the first switch unit. However, such an electrical resistance will mean permanent energy losses, in particular even while the energy supply arrangement is in the first operating state.

In a further advantageous embodiment of the invention, the current limiting device is designed as at least one electrical resistor permanently connected in parallel to the first switch unit. This also causes permanent energy losses, but if this electrical resistance is chosen to be large enough, the energy losses during the normal first operating state are extremely low. This represents a particularly simple and inexpensive design of the current limiting device.

In a further advantageous embodiment of the invention, the current limiting device is designed as at least one electrical resistor which can be switched in parallel with the first switch unit by means of a third switch unit. If, for example, you want to switch from the second operating state back to the first operating state, the third switch unit is first closed before the first switch unit changes to the closed state, which thus couples the at least two energy storage units to the input via this electrical resistor, so that now a limited equalizing current can flow from the energy source to the energy storage units and charge them, whereby their voltage increases and approximates that of the energy source again. Only when the differential voltage between the voltage present at the input and provided by the energy source and the individual voltages provided by the respective energy storage units falls below a predeterminable limit value, is the first switch unit closed and the third switch unit opened again, which now has the advantage that only during This transition phase from the second operating state into the first operating state shows energy losses due to this electrical resistance, but subsequently no longer in the first operating state. This represents a particularly simple, inexpensive and energy-efficient measure for current limitation.

In a further advantageous embodiment of the invention, the current limiting device is designed as a down converter arranged on the input side. This can be easily achieved, for example, with an additional inductance and an additional switch. An input capacitor may also be provided. The additional inductance is then preferably arranged in series with the first switch unit and between the first switch unit and the at least two energy storage units, in particular between the first switch unit and the circuit arrangement comprising the at least two energy storage units. The additional switch, which can also be configured as a semiconductor switch, for example as a MOSFET, is preferably located parallel to the circuit arrangement with the at least two energy storage units and is connected with a first connection between the first switch unit and the inductor and with a second connection Mass coupled. The optional capacitor can connect the two input connections. To operate this step-down converter, a first switch of the first switch unit can then be statically closed and a second switch of the first switch unit and the additional switch can be opened and closed alternately with pulse width modulation at a fixed switching frequency. A current regulator, which receives its input signal by measuring the drain-source voltage across the first switch of the first switch unit, is suitable for the controlled startup of the energy supply arrangement. When an accepted voltage difference between the input and the voltages of the energy storage units is reached, it can be switched on statically. This means that the clocking is switched off, the additional switch is opened and both switches of the first switch unit are now in the closed state. However, this represents only one training option for such a step-down converter. In addition to the described construction of this step-down converter, a MOSFET which is located parallel to the inductance can also be provided for bridging the inductance in normal operation, that is to say in the first operating state, of the energy supply arrangement. As a result, the losses in the inductance during normal operation can advantageously also be reduced.

These described precharging concepts can also be combined with one another in any desired manner and can advantageously be provided by one of the energy storage units used, regardless of the number.

Furthermore, the invention relates to an electrical system for a motor vehicle with an energy supply arrangement according to the invention or one of its Configurations. The advantages described for the power supply arrangement according to the invention and its configurations apply in the same way to the on-board electrical system according to the invention. The electrical system preferably represents a low-voltage electrical system.

In addition, the vehicle electrical system can have an electrical consumer group comprising the at least one electrical consumer, the vehicle electrical system being set up in such a way that in the first operating state each consumer of the electrical consumer group can be supplied with energy by the first supply voltage, and that in the second operating state only a selected, the consumer subgroup of the electrical consumer group comprising at least one electrical consumer is coupled to the output, so that only the selected consumer subgroup can be supplied with energy by the second supply voltage provided at the output. Thus, if required, those consumers or components can advantageously be specifically connected to the output of the energy supply arrangement or also permanently coupled to this output, for which a higher supply voltage is to be provided in accordance with the second operating state. Other consumers for which no higher supply voltage is to be provided at this point in time can either be decoupled from the output or can also be coupled from the outset to the energy supply arrangement only on the input side. In the second operating state, these consumers are then also decoupled from the energy supply arrangement by opening the first switch unit. Nevertheless, these consumers can still continue to be supplied by the additional energy source.

This energy source, which is coupled to the input of the energy supply arrangement in the first operating state, can represent, for example, an additional battery and / or a converter device, such as a DC / DC converter, which converts the low-voltage electrical system from a high-voltage electrical system and / or medium voltage - On-board electrical system supplied with energy.

It is further preferred that the at least one electrical consumer represents a servomotor of an electrical seat adjustment device of a seat. This has the advantages already described at the beginning, that in situations such as before an impending accident or in the event of certain faults in the vehicle in which the driver or other occupants should be brought into an optimal sitting position as quickly as possible using a conventional seat adjustment device, this is now sufficient is possible in a short time due to the higher output voltage provided. So far, this has not been possible with conventional 12-volt servomotors. Today's concepts, however, which offer higher seat adjustment speeds, require a significantly higher amount of additional components. The invention, on the other hand, makes it possible to use simple servomotors for seat adjustment, to offer comfort-enhancing functions during, for example, piloted driving, and at the same time to provide a sufficiently rapid seat adjustment to an optimal seating position in emergencies.

Furthermore, the invention also relates to a motor vehicle with an electrical system according to the invention or one of its configurations.

In addition, the invention also relates to a method for operating an energy supply arrangement for supplying at least one electrical consumer of a low-voltage electrical system of a motor vehicle, the energy supply arrangement having a first energy storage unit and at least a second energy storage unit, which are connected in parallel to one another at least in a first operating state and a predetermined one Provide the first supply voltage at an output of the energy supply arrangement for supplying the at least one electrical consumer. In addition, the energy supply arrangement has an input for coupling to an energy source, the energy supply arrangement having a first switch unit, which couples the first and the at least one second energy storage unit to the input in a closed state and decouples them from the input in an open state, wherein the energy supply arrangement has a second switch unit which, in a second operating state, switches the first and the at least one second energy storage unit in series in order to provide at the output a predetermined second supply voltage, which is greater than the first supply voltage, for supplying the at least one electrical consumer, wherein the first switch unit is in the second operating state in the open state and in the first operating state in the closed state.

The advantages described for the power supply arrangement according to the invention and its embodiments also apply in the same way to the method according to the invention.

The invention also includes further developments of the method according to the invention which have features as have already been described in connection with the further developments of the energy supply arrangement according to the invention. For this reason, the corresponding ones Further developments of the method according to the invention are not described again here.

The invention also includes combinations of the features of the described embodiments.

• 1 eine schematische Darstellung eines Kraftfahrzeug-Bordnetzes mit einem Niedervolt-Bordnetz, welches eine Energieversorgungsanordnung gemäß einem Ausführungsbeispiel der Erfindung aufweist;
• 2 eine schematische Darstellung der Energieversorgungsanordnung, welche mit einem elektrischen Verbraucher gekoppelt ist, gemäß einem Ausführungsbeispiel der Erfindung;
• 3 eine schematische Prinzipdarstellung der Energieversorgungsanordnung in einem ersten Betriebszustand;
• 4 eine schematische Prinzipdarstellung der Energieversorgungsanordnung in einem zweiten Betriebszustand gemäß einem Ausführungsbeispiel der Erfindung;
• 5 eine schematische Darstellung der Energieversorgungsanordnung mit drei Energiespeichereinheiten gemäß einem Ausführungsbeispiel der Erfindung;
• 6 eine schematische Darstellung der Energieversorgungsanordnung mit einer beliebigen Anzahl an Energiespeichereinheiten gemäß einem Ausführungsbeispiel der Erfindung; und
• 7 eine schematische Darstellung der Energieversorgungsanordnung und verschiedener Ausbildungsmöglichkeiten einer Strombegrenzungseinrichtung gemäß einem Ausführungsbeispiel der Erfindung.

Exemplary embodiments of the invention are described below. This shows:

• 1 a schematic representation of a motor vehicle electrical system with a low-voltage electrical system, which has an energy supply arrangement according to an embodiment of the invention;
• 2nd is a schematic representation of the power supply arrangement, which is coupled to an electrical consumer, according to an embodiment of the invention;
• 3rd a schematic diagram of the power supply arrangement in a first operating state;
• 4th a schematic diagram of the power supply arrangement in a second operating state according to an embodiment of the invention;
• 5 is a schematic representation of the energy supply arrangement with three energy storage units according to an embodiment of the invention;
• 6 a schematic representation of the energy supply arrangement with any number of energy storage units according to an embodiment of the invention; and
• 7 is a schematic representation of the power supply arrangement and various training options of a current limiting device according to an embodiment of the invention.

The exemplary embodiments explained below are preferred embodiments of the invention. In the exemplary embodiments, the described components of the embodiments each represent individual features of the invention that are to be considered independently of one another and that further develop the invention independently of one another. Therefore, the disclosure is intended to include combinations of the features of the embodiments other than those shown. Furthermore, the described embodiments can also be supplemented by further features of the invention that have already been described.

In the figures, the same reference numerals designate elements that have the same function.

1 shows a schematic representation of a motor vehicle electrical system 10th with a low-voltage electrical system 12th which is a power supply arrangement 13 has, according to an embodiment of the invention. In addition to the low-voltage electrical system 12th , which in this example is configured as a 12-volt electrical system, includes the motor vehicle electrical system 10th in this example a high-voltage electrical system 14 . This high-voltage electrical system 14 includes a high-voltage battery 16 with an assigned battery management system 18th . The power supply arrangement 16 is about two main shooters 20th that have a with the battery management system 18th coupled control unit 22 can be controlled with the rest of the high-voltage electrical system 14 can be coupled and uncoupled from this. The high-voltage battery 16 supplies various high-voltage consumers with energy, such as an electric air conditioning compressor 24th and power electronics 26 for one or two electric machines 28 , for example one for driving the rear axle and one for driving the front axle of the motor vehicle, or just a single electric machine 28 to drive either the rear axle or the front axle of the motor vehicle. For charging the high-voltage battery 16 the motor vehicle also has a charger 30th which also with the high-voltage electrical system 14 is coupled. The low-voltage electrical system 12th is via a converter device 32 , in particular a DC / DC converter with the high-voltage electrical system 14 is coupled, supplied with energy.

The DC / DC converter can in particular be designed bidirectionally. Basically, the embodiments of the invention described in more detail below relating to the energy supply arrangement can be 13 as well as the low-voltage electrical system 12th combine with any energy network architecture. For example, instead of the high-voltage electrical system described 14 also connect a medium-voltage electrical system or be additionally provided. In addition, the energy supply for the low-voltage electrical system 12th also in other ways than by a converter device 32 to be provided.

The low-voltage electrical system also includes 12th next to that as a converter device 32 trained energy source multiple electrical consumers 34 , 36 . Among them are consumers 34 , which require an operating voltage of 12 volts or generally a defined low-voltage voltage for operation. On the other hand, there are also consumers 36 that provide a higher operating voltage than that for the low-voltage electrical system 12th defined voltage, in this example 12 volts, can perform certain functions that would not be possible with the low-voltage voltage, such as a quick adjustment function for an electric seat adjustment. This is now advantageously done by the power supply arrangement 13 according to embodiments of the invention.

This in 1 low-voltage electrical system shown 12th was also expanded in this example with regard to the required higher availability, for example for a vehicle with highly automated driving functionalities. This low-voltage electrical system accordingly shows 12th an additional 12 volt battery 37, or in general an additional energy store, to reduce the probability of failure of the low-voltage electrical system 12th to minimize. This higher availability is now achieved by the fact that instead of only two energy suppliers, that is the DC / DC converter 32 and the power supply arrangement 13 , an additional energy supplier in the form of this additional 12-volt battery 37 is available and thus reduces the probability of simultaneous or immediately following failure of all energy sources in accordance with the individual failure probability. This additional energy storage too 37 is only optional and can also be omitted for other energy network topologies.

2nd shows a schematic and more detailed representation of the energy supply arrangement 13 that in this example with an electrical consumer 36 , such as a circuit arrangement with a servomotor designed as a DC motor 36a and with a four quadrant 36b , which is an electronic H-bridge circuit consisting of four semiconductor switches 36c having.

The power supply arrangement 13 now has an entrance 38 for coupling to an energy source, such as the DC / DC converter 32 , on, at this entrance 38 other consumers too 34 , as in 1 shown, can be connected. Furthermore, the power supply arrangement 13 an exit 40 on who in this example with the electrical consumer 36 is coupled, but can also be coupled with additional electrical consumers in a parallel connection. One of the two input ports 38 and one of the two output connections 40 lies on ground 42 .

Furthermore, the power supply arrangement 13 a first energy storage unit B1 on, and a second energy storage unit B2 . A respective one of these energy storage units B1 , B2 has, at least in the charged state, a total voltage that that for the low-voltage electrical system 12th defined voltage level, that is 12 volts in this example. In addition, the energy supply arrangement shows 13 a first switch unit 44 which is designed to, in a closed state, the first and the at least one second energy storage unit B1 , B2 with the entrance 38 to couple and in an open state from the entrance 38 to decouple.

The energy storage units B1 , B2 can be designed, for example, as a battery and / or as a capacitor, for example as a supercapacitor. Furthermore, the power supply arrangement 13 also a second switch unit 46 on, which is designed to the first and the second energy storage unit B1 , B2 to be connected in parallel to one another in a first operating state and to be connected in series to one another in a second operating state.

As in 2nd shown, comprises the first switch unit 44 a bidirectional switch, which is made up of two individual switches S1 , S2 is formed. These two single switches S1 and S2 can be provided for example by a MOSFET or other semiconductor switches. These two MOSFETs S1 , S2 are connected in series so that blocking is possible in both current directions. The second switch unit 46 also comprises several individual switches, in particular a first individual switch S3 , a second single switch S4 and a third single switch S5 , which are also designed as semiconductor switches, in particular as MOSFETs.

Here is the power supply arrangement 13 further set up such that the first switch unit 44 in the first operating state in the closed state and in the second operating state in the open state. Correspondingly, an equivalent circuit diagram for the energy supply arrangement results in the first operating state 13 as in 3rd shown and in the second operating state an equivalent circuit as in 4th shown.

3rd thus shows a schematic representation of an equivalent circuit diagram 13a the power supply arrangement 13 when it is in the first operating state. The two energy storage units are accordingly B1 , B2 connected in parallel to each other. A respective one of the energy storage units B1 , B2 represents a total tension U1 ready, the one at the exit 40 total voltage that can be tapped U1 corresponds.

The first switch unit is in the first operating state 44 and especially the individual switches S1 , S2 in the closed state, whereby the parallel connection of the two energy storage units B1 , B2 with the entrance 38 is coupled, so that in particular the parallel connection of the two energy storage units B1 , B2 provided total voltage U1 at the entrance 38 provided. The parallel connection of the two energy storage units B1 , B2 is realized in particular by the first single switch S3 is in the closed state, the second single switch S4 the second switch unit 46 is in the open state, and the third single switch S5 the second switch unit 46 is also in the closed state.

4th shows a schematic representation of the equivalent circuit diagram 13b the power supply arrangement 13 in the second operating state. The two energy storage units are in this second operating state B1 , B2 connected to each other in series. This is realized by the fact that the first individual switch is now open S3 the second switch unit 46 is in the open state, the second single switch S4 the second switch unit 46 is in the closed state, and the third single switch S5 the second switch unit 46 is also in the open state. In addition, this series connection of the two energy storage units B1 , B2 from the entrance 38 decoupled. This is accomplished by the first switch unit 44 and in particular their respective individual switches S1 , S2 are each in the open state. By connecting the two energy storage units in series B1 , B2 will be at the exit 40 a total tension U2 provided, which is now larger than that at the exit 40 provided total voltage U1 in the first operating state of the energy supply arrangement 13 . In particular, this is at the exit 40 provided total voltage U2 in the second operating state the sum of the individual voltages U1 by the respective energy storage units B1 , B2 provided.

This switchover option, which is provided by the energy supply arrangement 13 is provided, it is now advantageously possible for certain consumers 36 possibly with a higher supply voltage U2 to supply. This can be useful, for example, in certain error cases. For example, all energy sources are initially diagnosed with regard to their functionality. If a failure of an energy source is diagnosed, the vehicle can initiate countermeasures in accordance with the fault tolerance times taken into account. In the case of a piloted vehicle, such a countermeasure is, for example, the initiation of driver takeover. In the event of a fault, the driver handover can take a long time in accordance with the minimum energy content of the energy stores without creating an additional safety risk. Any seat adjustment that may be required in order to bring the driver back into the optimum seating position for taking over the driving task can, for example, run at normal seat adjustment speed. For other vehicle malfunctions that require driver takeover, it may be necessary to accelerate driver takeover accordingly. This in turn requires a significantly faster seat adjustment. For such a faster seat adjustment and the associated higher performance of the servomotors, a briefly higher operating voltage can now advantageously be used U2 be used. The generation of a higher operating voltage U2 would in principle also be possible with corresponding control units with built-in step-up converters, but increases the effort in the component of the seat adjustment accordingly. Through the too 3rd Modification described of a conventional, for the low-voltage electrical system 12th provided energy storage unit as the described energy supply arrangement 13 enables the higher operating voltage to be provided U2 in a much simpler and cheaper way.

The power supply arrangement 13 can also do more than the two energy storage units shown so far B1 , B2 according to the two-stage concept, as in 5 and 6 is shown. 5 shows in addition to the two-stage concept already described, an energy supply arrangement 13 with a three-stage concept, i.e. with three energy storage units B1 , B2 , B3 and 6 a corresponding N-stage concept, that is with N Energy storage units B1 , B2 , B3 , ..., BN , each with a corresponding topology extension. This means that the second switch unit 46 has three further individual switches for each additional energy storage unit provided. With the three-stage concept, as in 5 shown, the second switch unit 46 So for the additional energy storage unit B3 the additional switches S6 , S7 and S8 on. To implement a parallel connection of all three energy storage units B1 , B2 , B3 are the switches accordingly S3 , S5 , S6 , S8 closed and the switches S4 , S7 open. In the second operating state, that is when all energy storage units B1 , B2 , B3 in terms of the exit 40 are connected in series, so are the switches accordingly S4 , S7 closed and the switches S3 , S5 , S6 , S8 open. In a corresponding manner, the second switch unit comprises 46 For N Energy storage units B1 , B2 , B3 , ..., BN in the 6 additionally shown switch S9 , S10 , ..., SX. The first switch unit 44 can, however, remain unchanged regardless of the number of levels of the concept to be implemented.

According to the resulting number of energy storage units B1 , B2 , B3 , ..., BN the output voltage increases accordingly U2 in the second operating state. This allows the energy supply arrangement 13 Implement and expand in a particularly simple way for the respective requirements.

In the event that the battery module is switched on, that is to say the energy supply arrangement 13 , to the 12-volt power network or in general to the low-voltage on-board network 12th , that is if the power supply arrangement 13 The energy supply arrangement can be converted from the second operating state to the first operating state 13 and in particular their respective energy storage units B1 , B2 , B3 , ..., BN depending on their energy content from the supply voltage, that is to say from the energy source, in particular the converter device 32 , provided voltage, which then again at the input 38 should be different. With a simple connection of the MOSFETs S1 and S2 high compensation currents could then result due to the high-current design of the battery system, which could influence the energy network inadmissibly, but could also damage the semiconductors.

In the event of a higher voltage of the individual energy storage units B1 , B2 can the connected components 36 at the exit 40 the power supply arrangement 13 ensure that the voltages are balanced by connecting them. The two switches S1 and S2 the first switch unit 44 then remain open until the differential voltage becomes minimal. In the event of a lower resulting voltage of the energy storage units B1 , B2 , B3 , ..., BN it is accordingly advantageous to provide a possibility for the individual energy storage units B1 , B2 , B3 , ..., BN to the supply voltage, that is to say that from the energy source 32 provided voltage, which in turn after the transition to the first operating state at the input 38 the power supply arrangement 13 to reload. This is in 7 using an example with only two energy storage units B1 , B2 shown.

7 shows a schematic representation of the power supply arrangement 13 which now advantageously has a current limiting device 48a, 48b for current limitation during the transition from the second operating state to the first operating state. In particular, in 7 several ways of designing this current limiting device 48a , 48b shown. A particularly simple option in terms of circuitry is to design the current limiting device according to the first variant 48a , according to which a bypass circuit of a precharge resistor 50 it is provided which is switched on or off depending on the situation. This switching on or off is done by a third switch unit 52 realized. So there is the energy supply arrangement 13 in the second operating state and accordingly the first switch unit 44 in the open state, and should now be changed back to the first operating state, the energy storage units are first again B1 , B2 by means of the second switch unit 46 connected in parallel to each other and connect them via the third switch unit 52 , which was in the open state during the second operating state, by closing with the input 38 coupled, whereby the respective energy storage units B1 , B2 via the converter device 32 be charged until their individual voltages U1 again to those in the low-voltage electrical system 12th existing voltage, that is to say 12 volts, has equalized or until the voltage difference falls below a predeterminable limit value. Then the first switch unit 44 closed and the third switch unit 52 can be opened, causing further energy losses due to the pre-charging resistor 50 can be avoided.

Optionally, the third switch unit 52 in this embodiment the current limiting device 48a also dropped. In this case it is advantageous if the precharge resistor 50 is chosen as large as possible. This can then be permanently parallel to the first switch unit 44 stay switched. During the first operating state, the energy losses are due to this pre-charging resistor 50 relatively low, since due to its large size, relatively little current flows through this parallel current path. However, it is preferred to use this third switch unit 52 to be provided as this is a smaller dimensioning of the precharging resistor 50 allows, which advantageously shortens the precharge time and the effort in the thermal connection of the precharge resistor 50 decreased.

In a further advantageous variant 48b the current limiting device are an additional inductance I and an additional switch S11 intended. Depending on the electromagnetic compatibility regulations, an input capacitor can also be used C. be provided as in 7 is shown. This variant 48b provides an additional integrated step-down converter at the entrance 38 the power supply arrangement 13 represents, in particular a second order low-pass filter, which is designed for the energy storage units B1 , B2 pre-charged under current control until the resulting input voltage is reached. To operate this integrated buck converter 48b becomes the switch S1 the first switch unit 44 statically closed and the second switch S2 the first switch unit and the additional switch S11 with a fixed switching frequency, alternately pulse width modulated opened and closed. For the controlled startup of the energy supply arrangement 13 offers a current regulator, which by measuring the drain-source voltage across the first switch S1 the first switch unit 44 receives its input signal. When you reach one accepted voltage difference between input 38 and the respective energy storage units B1 , B2 can be switched on statically. For this, the clocking is switched off, the additional switch S11 opened and the second switch S2 the first switch unit 44 additionally closed statically. The drivers of the semiconductors can be provided according to the static and dynamic use.

In addition, a MOSFET, which is parallel to the inductance I, or in general a further switch, can optionally be used to bridge the inductance I in the first operating state of the energy supply arrangement 13 for which purpose this parallel further switch is closed after the transition phase in the first operating state, in particular is also closed in the second operating state and is only open during the transition phase. As a result, the losses in inductance I can be reduced during the first operating state and also during the second operating state.

The precharge concepts explained here, i.e. the various training options for the current limiting device 48a , 48b can regardless of the number of stages or regardless of the number of energy storage units used B1 , B2 , B3 , ..., BN be integrated completely analog.

Overall, the examples show how the invention provides an energy supply arrangement, an on-board electrical system and a method for operating an energy supply arrangement, which make it possible in certain situations to decouple a battery in the form of an energy supply arrangement from the rest of the energy system, that is to say in the low-voltage electrical system in order to modify them by internal switching so that a multiple operating voltage is available for connected components at short notice. This operating voltage can be used by control units in the vehicle, for example for servomotors, which are supposed to achieve higher outputs and speeds in the short term. For example, this is necessary in the event of a necessary seat adjustment in the event of a fault during highly automated driving, in which the driver is to be brought into the driving task faster from his rest position than would be possible with today's actuators. Another application is the quick seat adjustment before a possible accident in order to optimize the effectiveness of the restraint systems.

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102015010531 A1 [0002]
• DE 102014201351 A1 [0002, 0003]

Claims (10)

Energy supply arrangement (13) for supplying at least one electrical consumer (36) to a low-voltage electrical system (12) of a motor vehicle, the energy supply arrangement (13) comprising: - an output (40) for coupling to the at least one electrical consumer (36); - a first energy storage unit (B1); and - at least one second energy storage unit (B2, B3, BN); - The first and the at least one second energy storage unit (B1, B2, B3, BN) are connected in parallel in a first operating state and are designed to, in the first operating state, a predetermined first supply voltage (U1) at the output (40) for supplying the to provide at least one electrical consumer (36), characterized by - an input (38) for coupling to an energy source (32); - a first switch unit (44), which is designed to couple the first and the at least one second energy storage unit (B1, B2, B3, BN) to the input (38) in a closed state and in an open state to the input (38) 38) to decouple, the first switch unit (44) being in the first operating state in the closed state and being in the second operating state in the open state; - A second switch unit (46), which is designed to connect the first and the at least one second energy storage unit (B1, B2, B3, BN) in series in the second operating state in order to provide a predetermined second supply voltage (U2 ), which is greater than the first supply voltage (U1) to supply the at least one electrical consumer (36). Energy supply arrangement (13) after Claim 1 , characterized in that the energy supply arrangement (13) has a current limiting device (48a, 48b), which is designed, in a transition from the second operating state to the first operating state, in a state coupled via the input (38) to the energy source (32) Energy supply arrangement (13) to limit a compensation current flowing from the energy source (32) to the first and at least one second energy storage unit (B1, B2, B3, BN). Energy supply arrangement (13) after Claim 2 , characterized in that the current limiting device is designed as at least one electrical resistor arranged in series with the first switch unit (44). Energy supply arrangement (13) according to one of the Claims 2 or 3rd , characterized in that the current limiting device (48a) is designed as at least one electrical resistor (50) permanently connected in parallel to the first switch unit (44). Energy supply arrangement (13) according to one of the Claims 2 to 4th , characterized in that the current limiting device (48a) is designed as at least one electrical resistor (50) which can be switched in parallel with the first switch unit (44) by means of a third switch unit (52). Energy supply arrangement (13) according to one of the Claims 2 to 5 , characterized in that the current limiting device (48b) is designed as a down converter (48b) arranged on the input side. Vehicle electrical system (10, 14, 12) for a motor vehicle with an energy supply arrangement (13) according to one of the preceding claims. Vehicle electrical system (12) Claim 7 characterized in that the electrical system (12) has an electrical consumer group (34, 36) comprising the at least one electrical consumer (36), the electrical system (12) being set up in such a way that in the first operating state each consumer (34, 36) the electrical consumer group (34, 36) can be supplied with energy by the first supply voltage (U1), and that in the second operating state only a selected consumer subgroup (36) of the electrical consumer group (34, 36) comprising at least one electrical consumer (36) is included is coupled to the output (40), so that only the selected consumer sub-group (36) can be supplied with energy by the second supply voltage (U2) provided at the output (40). Vehicle electrical system (12) according to one of the Claims 7 or 8th , characterized in that the at least one electrical consumer (36) represents a servomotor (36a) of an electrical seat adjustment device of a seat, in particular a driver's seat. Method for operating an energy supply arrangement (13) for supplying at least one electrical consumer (36) of a low-voltage electrical system (12) of a motor vehicle, the energy supply arrangement (13) having a first energy storage unit (B1) and at least a second energy storage unit (B2, B3, BN) ), which are connected in parallel to one another at least in a first operating state and a predetermined first supply voltage (U1) at an output (40) of the energy supply arrangement (13) for supplying the at least one electrical one Providing the consumer (36), characterized in that the energy supply arrangement (13) has an input (38) for coupling to an energy source (32), the energy supply arrangement (13) having a first switch unit (44) which, in a closed state, switches the coupling the first and the at least one second energy storage unit (B1, B2, B3, BN) to at least one input (38) and decoupling them from the input (38) in an open state, the energy supply arrangement (13) having a second switch unit (46) which, in a second operating state, connects the first and the at least one second energy storage unit (B1, B2, B3, BN) in series in order to have a predetermined second supply voltage (U2) at the output (40) which is greater than the first supply voltage (U1 ) to supply the at least one electrical consumer (36), the first switch unit (44) being in the second operating state in the open state located and in the first operating state in the closed state.

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