DE102011011800B4 - Method for power supply for a vehicle and corresponding device and vehicle - Google Patents

Abstract

Method for power supply for a vehicle (10), wherein a voltage network (1) of the vehicle (10) by at least one first energy storage (3, 4) is supplied with voltage, wherein the at least one first energy storage a high-voltage energy storage (4) and a low-voltage energy store (3), the high-voltage energy store (4) being coupled to the low-voltage network (1) via at least one DC-DC converter (5; 15) for supplying energy to a low-voltage network (1), one passing through the at least one first energy store (3, 4) effected power supply of the voltage network (1) is monitored, wherein a second energy storage (6) for supplying power to the voltage network (1) is only connected when detected in the monitoring that the power supply of the voltage network (1) the at least one first energy store (3, 4) is disturbed, this being the case when the high-voltage energy store (4) or the Gleichspsp age converter (5; 15) has a defect, and wherein the voltage network is the low-voltage network (1).

Description

The present invention relates to a method for maintaining the power supply in a vehicle, in particular in an emergency, as well as a correspondingly configured device and a correspondingly configured vehicle.

The DE 102 51 589 A1 describes a vehicle electrical system for a vehicle with two sub-board networks, in each of which a battery is available. A consumer is supplied with different supply voltages via the two sub-systems. Depending on the state of charge of the batteries, the consumer is connected to the more efficient onboard power supply.

The DE 10 2005 004 330 A1 discloses a vehicle electrical system for a vehicle with a base-board network with a battery and an auxiliary electrical system with two batteries. The supply of a safety-relevant consumer takes place in case of failure of the base-board network with the help of the batteries of the auxiliary electrical system.

The DE 10 2008 010 979 A1 describes a vehicle electrical system for a vehicle with a base vehicle network with a battery and a subnet with an auxiliary battery, which is completed via a voltage converter to the base board network. If a short circuit occurs in the voltage converter, a switch is opened to disconnect the voltage transformer from the subnet and a consumer is at least temporarily powered by the auxiliary battery.

The DE 100 20 302 A1 discloses a vehicle electrical system comprising a battery, a consumer and a consumer associated short-term energy storage. The consumer and the short-term energy storage are arranged in a sub-board network, which is connected by a DC-DC converter with the rest of the vehicle electrical system. In the sub-board network an emergency battery is arranged, on the one hand in case of defect of the DC-DC converter or the vehicle electrical system, the base load of the consumer and the other hand, temporarily covered by the DC-DC converter and the short-term energy storage energy contributions.

The DE 10 2007 029 025 A1 describes a motor vehicle electrical system with a first electrical system branch, which includes a first load and a voltage source connected in parallel, with a second electrical system branch, which includes a second load and a parallel switchable capacitor, with a DC-DC converter through which the first electrical system branch with the second electrical system branch can be coupled, and with a parallel to the DC-DC converter switched switch, is bridged by the DC switching in the closed state. At a strong voltage dip in the first electrical system branch of the switch is opened so that the voltage drop does not affect the second electrical system branch.

The US 2004/0112320 A1 discloses a motor vehicle network comprising two batteries (one 36V and one 12V rated) and a double-layer capacitor. The batteries and the double-layer capacitor are connected to each other via DC-DC converters to compensate for voltage fluctuations.

The EP 1 013 506 A2 describes an electrical system for a motor vehicle with a DC-DC converter with a downstream supercapacitor. Under certain operating conditions, the energy stored in this supercapacitor is made available to the electrical system.

The DE 102 14 498 A1 discloses two low-voltage batteries, each connected to a switch with consumers.

The DE 10 2009 043 878 A1 describes a method to support a power supply of an energy storage of a vehicle electrical system in the short term by a capacitor is switched on.

The EP 1 810 861 B1 describes a vehicle drive system in which two energy storage systems are controlled depending on current and voltage sensors.

The EP 1 366 948 A1 discloses a hybrid power system comprising a double-layer capacitor, an energy storage, and two DC-DC converters. In this case, the double-layer capacitor is connected to a load via a DC-DC converter and to the energy store via the second DC-DC converter.

The DE 102 20 939 A1 describes a method for controlling a DC-to-DC converter via which a high-voltage battery pack is connected to a low-voltage battery pack.

The EP 1 360 090 B1 discloses a motor vehicle electrical system, wherein an AC / DC converter charges a double-layer capacitor and an accumulator.

The DE 103 05 058 B3 describes a power supply circuit for a vehicle electrical system with a starter-generator, power electronics, a battery, a dynamic energy storage and a DC-DC converter.

The vehicle electrical system for vehicles according to the prior art, in which an electric motor is used to drive the vehicle, is typically in a high-voltage network (eg voltage range 100 to 800 V) and in a low-voltage network (eg voltage range 9-15 V, for trucks up to 24 V). As in 1 is shown, is the high-voltage network 2 via a DC-DC converter 5 with the low voltage network 1 connected. By means of the high-voltage network 2 become different high-voltage consumers, such as an electric motor 13 , an air conditioning compressor 14 or a positive temperature coefficient (PTC) heater, typically powered by a high-voltage, high-performance battery 4 and / or a generator. The low voltage network 1 supplies various low-voltage consumers, such as control units with energy, whereby these control units can be subdivided into control units for comfort functions and control units for safety-relevant functions. The comfort features include, for example, an occupant interface (HMI ("Human Machine Interface")), a window heating, interior lighting 11 or an electric window, whereas an electromechanical steering, a brake booster 12 or a headlight to the safety-related functions are counted. About the already mentioned DC-DC converter 5 becomes the low voltage network 1 and thus also a low-voltage energy storage 3 with voltage from the high-voltage network 2 provided.

Even in case of failure, when the power supply with the help of the high-voltage network is no longer given, nor safety-critical functions such as the electromechanical steering or the brake assist 12 ensure is the low-voltage energy storage 3 designed such that it can provide the necessary energy for a certain amount of time. In addition, the low-voltage energy storage is able to apply or compensate for a certain peak current during normal operation.

The present invention has as its object to provide a concept for supplying power to a vehicle with high-voltage network, so that the low-voltage energy storage can be made smaller and lighter, without causing any restrictions in the safety-related functions of the vehicle in case of failure.

According to the invention this object is achieved by a method for power supply according to claim 1, by a device for power supply according to claim 4 and by a vehicle according to claim 9. The dependent claims define preferred and advantageous embodiments of the present invention.

In the context of the present invention, a method for supplying power to a vehicle is provided. The voltage network of the vehicle is supplied by several first energy storage with voltage. An energy supply of the voltage network by means of the first energy storage is monitored. A second energy storage is only connected to the power supply of the voltage network when it is detected in this monitoring that the power supply of the power network is disturbed by the first energy storage.

Since the voltage network is the low-voltage network of a vehicle, and since the first energy stores comprise both a high-voltage energy store and a low-voltage energy store, the low-voltage energy store for normal operation can be a much smaller energy store with a much smaller energy content , as is the case today in the state of the art. This is due to the fact that the low-voltage energy storage only needs to cover the peak current, since it does not need to worry about the fault that the voltage or low-voltage network is no longer supplied with power. Either the low-voltage network (and thus also the low-voltage energy storage) is powered by the high-voltage energy storage via a DC-DC converter or if this energy supply is disturbed by the high-voltage energy storage, then the low-voltage network is powered by the second energy storage. Also, the second energy storage, since it is used only in an emergency, are designed to be very small and inexpensive, since he does not need to be rechargeable, for example, or at least not designed for as many charging cycles as the normally used low-voltage energy storage.

The power supply of the voltage network through the at least one first energy storage is then considered disturbed when the power supply of the low-voltage network is disturbed by the high-voltage energy storage. This is the case when the high-voltage energy storage or the DC-DC converter has a defect.

According to the invention, it is also possible for at least a part (better all) of consumers supplied by the voltage network, which do not exercise safety-relevant functions of the vehicle, to be deactivated when it is detected that the power supply of the voltage network is disturbed by means of the at least one first energy store. This deactivation concerns in particular the of Low-voltage network supplied consumers and serves to reduce the necessary electrical energy consumption. The smaller this necessary electrical energy consumption, the lower the electric charge to be stored by the second energy store can be.

• • Eine Unterstützung einer elektromechanischen Lenkung des Fahrzeugs.
• • Eine Unterstützung eines Bremskraftverstärkers des Fahrzeugs.
• • Eine Beleuchtungsfunktion (insbesondere eine Warnblinkerfunktion) des Fahrzeugs.

A consumer should continue to be supplied with power in an emergency when a power failure through the first energy storage (especially high-voltage energy storage) is detected when he performs a safety-related function for the vehicle. The following functions are classified as security-relevant:

• • A support of an electromechanical steering of the vehicle.
• • A support of a brake booster of the vehicle.
• • A lighting function (in particular a hazard warning function) of the vehicle.

In the context of the present invention, a device for supplying power to a vehicle is also provided. In this case, the device comprises a plurality of first energy stores in order to supply a voltage network of the vehicle with voltage. In addition, the device comprises a controller and a second energy store, which can be connected to the power supply of the voltage network. The controller is configured such that it monitors the power supply of the voltage network through the first energy storage. Only when the controller detects in this monitoring that the power supply of the voltage network is disturbed by the first energy storage, the controller switches the second energy storage to the power supply of the voltage network added.

The advantages of the device according to the invention essentially correspond to the advantages of the method according to the invention, which are carried out in advance in detail, so that a repetition is dispensed with here.

The device may also include a DC-DC converter, by means of which the second energy store can be connected to the voltage network.

By the second energy storage is connected via a DC-DC converter with the voltage network, advantageously also energy storage types, such as double-layer capacitors (DLCs ("Double Layer Capacitor")), as a second energy storage or emergency energy storage can be used.

Moreover, it is possible according to the invention that the device comprises a damping element, by means of which the second energy store is connected to the voltage network. This damping element is designed for damping voltage peaks and current peaks of the voltage network.

Since the second energy store is advantageously connected to the voltage network via the damping element, the second energy store only has to be designed to cope with low current and / or voltage peaks, since higher current and / or voltage peaks are correspondingly damped by the damping element. Such current and / or voltage peaks occur, for example, when consumers, which are supplied by the power supply, are turned on or off.

In a preferred embodiment of the invention, the device comprises a switch via which the second energy store can be connected to the voltage network or separated from it. Only when the controller detects that the power supply of the voltage network is disturbed by the first energy storage, the controller switches the switch such that the second energy storage is connected to the power grid. In contrast, during normal operation (ie the first energy stores supply the voltage network with energy), the second energy store is normally disconnected from the voltage supply by the switch.

As a result, the second energy store is advantageously connected to the voltage network only in the event of a fault (that is, in the event of a fault in the power supply of the voltage network through the first energy store). If such an error occurs only rarely, can be used as a second energy storage and a low-cost disposable energy storage (eg, a non-rechargeable energy storage).

Finally, in the context of the present invention, a vehicle is provided, which comprises a device according to the invention.

The present invention is particularly suitable for vehicles which comprise an electric motor for driving, that is, for example, for electric vehicles or hybrid vehicles. Of course, the present invention is not limited to this preferred field of application, since the present invention can be used in principle for vehicles without electric motor for propulsion or even in ships, aircraft and track-bound or track-guided vehicles. In addition, the use of the present is also Invention outside a means of locomotion, for example in the household to power important components, conceivable.

In the following, the present invention will be described in detail by means of embodiments according to the invention with reference to the figures.

In 1 shows the voltage supply of a voltage network of a vehicle according to the prior art.

In 2 a first embodiment according to the invention of a voltage supply of a voltage network of a vehicle is shown.

In 3 a second embodiment according to the invention of a voltage supply of a voltage network of a vehicle is shown.

In 4 a third embodiment according to the invention of a voltage supply of a voltage network of a vehicle is shown.

In 5 a vehicle according to the invention is shown with a device according to the invention.

As previously related to 1 has been explained, the low-voltage network 1 through the high-voltage network 2 energized. To the energy supply of the low-voltage network 1 To design safer, according to the invention, a further DC-DC converter may be present to the high-voltage energy storage 4 directly with the low-voltage network 1 connect to. As a result, the probability of failure of the energy supply of the low-voltage network 1 through the high-voltage network, better through the high-voltage energy storage 4 , is further reduced, can advantageously be the low-voltage energy storage 3 be significantly reduced because it only in the extreme emergency (eg in case of failure of both DC-DC converters) without power from the high-voltage network 2 Must work. This advantageously also the use of other types for the low-voltage energy storage 3 such as double-layer capacitors (eg, ultra-caps), hybrid double-layer capacitors (eg, a combination of a lithium-ion battery and a double-layer capacitor), or lithium-ion batteries.

However, in this case too, the energy supply of the low-voltage network should 1 be dimensioned so that in an emergency (ie when the low-voltage network 1 no longer from the high-voltage network 2 can be supplied) all safety-related functions of the vehicle remain operational until the vehicle is in a safe state. It can be regarded as a safe state on the one hand, a vehicle at a standstill, on the other hand, however, it is also possible that a safe state includes an active hazard warning function of the vehicle. In other words, in the first case, a power supply for the low-voltage network 1 be provided in an emergency, so that safety-related functions (eg brake and steering) are supplied with energy until the vehicle is at a standstill, in the latter case additionally the energy to supply the hazard warning function over a certain period of time must be provided.

For the design of one or more energy storage units for the low-voltage network 1 On the one hand, a peak current to be covered during normal operation and, on the other hand, the necessary energy requirement for transferring the vehicle into the safe vehicle state must be taken into account.

In order to meet the first criterion (peak current to be covered in normal operation), only an energy store with a low energy content is required, which, above all, is able to compensate for short-term high peak currents. However, the second criterion (meeting energy needs for safe-to-vehicle conversion) requires energy storage with a higher energy content. Since the low-voltage energy storage according to the prior art meets both criteria, it disadvantageously has a high weight and a high space requirement and is expensive both in terms of production and as regards its maintenance costs.

The basic idea of the present invention is now two energy stores for supplying energy to the low-voltage network 1 in normal operation and in an emergency (ie when the power supply of the low-voltage network fails 1 through the high-voltage network 2 ). In this case, one of the energy stores fulfills the first criterion (thus covers the peak current during normal operation), and the other energy store has an energy content which is large enough, in particular, to transfer the vehicle to the safe vehicle state only in an emergency.

In 2 is a first embodiment according to the invention of a voltage supply of a voltage network, in this case a low-voltage network 1 represented. Compared to the power supply of the prior art (see 1 ) exists in this voltage supply to a parallel to the DC-DC converter 5 another DC-DC converter 15 , with which the high-voltage energy storage 4 directly with the low-voltage network 1 connected is. In addition, there is also a controller 7 , a note energy store 6 and a switch 8th available. The control 7 detects information of both the DC-DC converter 5 as well as the other DC-DC converter 15 so the controller 7 in a position is a failure of both DC-DC converters 5 . 15 to recognize. Is through the controller 7 an emergency detected (for example, the failure of both DC-DC converter 5 . 15 ) becomes the note energy store 6 over the switch 8th switched on, so the low-voltage network 1 now in addition to the low-voltage energy storage 3 from the note energy store 6 is energized.

In addition, the controller is 7 with non-safety consumers (for example, the interior lighting 11 and the radio 17 ) in connection. This is the control 7 able to in an emergency these non-security consumers 11 . 17 to reduce the power requirement in an emergency on.

As the low-voltage energy storage 3 Peak voltages and peak currents balances, the Notenergiespeicher 6 be designed for an average emergency power consumption. In other words, the Notenergiespeicher 6 advantageously be designed with a correspondingly lower energy capacity, since he must supply or compensate for peak voltages or peak currents. In addition, as a Notenergiespeicher 6 a low-cost primary energy storage (for example, a non-rechargeable energy storage) are used, since it is assumed that the emergency described above occurs extremely rarely and consequently a replacement of the note energy storage after such an emergency seems reasonable.

Furthermore, it is conceivable the controller 7 interpreted as such that they after the standstill of the vehicle in an emergency (ie the failure of both DC-DC converter 5 . 15 ) further safety-relevant consumers, for example, the brake booster or the electromechanical steering disabled, so that only required at standstill safety-relevant consumers, such as the hazard warning lights and / or telecommunications facilities are activated. As a result, the power consumption of the Notenergiespeichers can be further reduced.

The energy content of the Notenergiespeichers 6 can in normal operation depending on the type of the used energy memory 6 (eg by reloading) by the controller 7 or by other control means (not shown).

It should be noted that according to the invention it is likewise possible for more than one note energy store to be present. Each additional note energy storage creates additional redundancy, which further increases the overall system reliability. If several Notenergiespeicher available, so for example, one or more of these Notenergiespeicher be switched on even when in normal operation of the low-voltage energy storage 3 has an error to the potential total peak current in the low-voltage network by this connection 1 increase accordingly.

In 3 a second embodiment according to the invention of a power supply for a vehicle is shown. Compared to the in 2 illustrated first embodiment, the power supply in 3 instead of a switch 8th a DC-DC converter 25 on, over which the Notenergiespeicher 6 with the low voltage network 1 is coupled. In this case, the DC-DC converter 25 be switchable, so the controller 7 is able to save the note energy 6 over the DC-DC converter 25 only in an emergency with the low voltage network 1 connect to.

Through the use of a DC-DC converter for coupling the Notenergiespeichers 6 to the low voltage network 1 come as energy storage and types such. As a double-layer capacitor, in question, which without DC-DC converter 25 not useful for powering a low-voltage network 1 can be used in the vehicle.

In 4 a third embodiment of a power supply for a vehicle according to the invention is shown. Compared to the first and second embodiments, the note memory is in the third embodiment 6 permanently via a damping element 16 with the low voltage network 1 connected. This damping element 16 dampens accumulating voltage or current peaks in the low-voltage network 1 and thereby advantageously allows a Notenergiespeicher 6 , which is designed only to supply an average energy demand.

Finally shows 5 an inventive vehicle 10 which is a device according to the invention 20 includes. This device according to the invention 20 to power the vehicle 10 in turn includes a controller 7 and a note energy store 6 ,

• • Das Vorhandensein eines Notenergiespeichers reduziert das Gesamtgewicht, das Gesamtvolumen und die Gesamtkosten zur Spannungsversorgung eines Niedervoltnetzes in einem Fahrzeug.
• • Das Vorhandensein eines Notenergiespeichers erhöht die Gesamtsystemausfallsicherheit des Fahrzeugs.
• • Je nach Einsatzart des Notenergiespeichers (wird nur im Notfall zugeschaltet oder ist mittels eines Gleichspannungswandlers zugeschaltet) kann im Vergleich zum normalen Niedervolt-Energiespeicher ein sehr preisgünstiger Energiespeicher eingesetzt werden.
• • Je nach Art des eingesetzten Notenergiespeichers können auch die Wartungskosten entsprechend gesenkt werden.

The present invention has the following advantages:

• • The presence of a note energy memory reduces the total weight, the total volume and the total cost of supplying power to a low-voltage network in a vehicle.
• • The presence of a note energy storage increases the overall system reliability of the vehicle.
• • Depending on the nature of the note energy storage (is only switched on in an emergency or is switched by means of a DC-DC converter) can be used in comparison to the normal low-voltage energy storage a very low-cost energy storage.
• • Depending on the type of used energy memory and the maintenance costs can be reduced accordingly.

Claims (9)

Method for supplying power to a vehicle ( 10 ), whereby a voltage network ( 1 ) of the vehicle ( 10 ) by at least one first energy store ( 3 . 4 ) is supplied with voltage, wherein the at least one first energy storage a high-voltage energy storage ( 4 ) and a low-voltage energy storage ( 3 ), wherein the high-voltage energy storage ( 4 ) via at least one DC-DC converter ( 5 ; 15 ) for the energy supply of a low-voltage network ( 1 ) with the low-voltage network ( 1 ), wherein one of the at least one first energy store ( 3 . 4 ) caused power supply of the voltage network ( 1 ), wherein a second energy store ( 6 ) for the power supply of the voltage network ( 1 ) is only connected when it is detected in the monitoring that the power supply of the voltage network ( 1 ) by the at least one first energy store ( 3 . 4 ), this being the case when the high-voltage energy storage ( 4 ) or the DC-DC converter ( 5 ; 15 ) has a defect, and wherein the voltage network is the low-voltage network ( 1 ). A method according to claim 1, characterized in that to reduce an electrical energy consumption at least a portion of the voltage from the network ( 1 ) furnished. Consumer ( 11 . 17 ), which have no safety-contributing function, are deactivated when it is detected that the power supply of the voltage network ( 1 ) by the at least one first energy store ( 3 . 4 ) is disturbed. Method according to claim 2, characterized in that a consumer ( 12 ) has a contributing safety function, if the consumer ( 12 ) has at least one of the following functions: • a support of a steering of the vehicle ( 10 ), • a support of a braking of the vehicle ( 10 ), and • a hazard warning function of the vehicle ( 10 ). Device for powering a vehicle ( 10 ), the device ( 20 ) at least one first energy store ( 3 . 4 ) for supplying a voltage network ( 1 ) of the vehicle ( 10 ) comprising voltage, wherein the at least one first energy store a high-voltage energy storage ( 4 ) and a low-voltage energy storage ( 3 ), wherein the high-voltage energy storage ( 4 ) via at least one DC-DC converter ( 5 ; 15 ) for the energy supply of a low-voltage network ( 1 ) with the low-voltage network ( 1 ), the device ( 20 ) a controller ( 7 ) and a second energy store ( 6 ), wherein the second energy store ( 6 ) for the power supply of the voltage network ( 1 ), the controller ( 7 ) for monitoring a power supply of the voltage network ( 1 ) by the at least one first energy store ( 3 . 4 ), wherein the controller ( 7 ) is configured, the second energy storage ( 6 ) for the power supply of the voltage network ( 1 ) only when the controller ( 7 ) detects that the power supply of the voltage network ( 1 ) by the at least one first energy store ( 3 . 4 ), this being the case when the high-voltage energy storage ( 4 ) or the DC-DC converter ( 5 ; 15 ) has a defect, and wherein the voltage network is the low-voltage network ( 1 ). Device according to claim 4, characterized in that the device ( 20 ) a DC-DC converter ( 25 ), via which the second energy store ( 6 ) with the voltage network ( 1 ) is connectable. Apparatus according to claim 4 or 5, characterized in that the device comprises a damping element ( 16 ), via which the second energy store ( 6 ) with the voltage network ( 1 ) is connectable, and that the damping element ( 16 ) is designed for damping voltage peaks and current peaks. Device according to one of claims 4-6, characterized in that the device ( 20 ) a switch ( 8th ), via which the second energy store ( 6 ) with the voltage network ( 1 ) and separable from it, and that the controller ( 7 ) is configured, the second energy storage ( 6 ) via the switch ( 8th ) with the voltage network ( 1 ) connect to. Device according to one of claims 4-7, characterized in that the device ( 20 ) is designed for carrying out the method according to one of claims 1-3. Vehicle with a device ( 10 ) according to any one of claims 4-8.

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