DE102015200121A1 - Method for monitoring a vehicle electrical system - Google Patents

Abstract

The invention relates to a method for operating a vehicle electrical system having a plurality of vehicle electrical system paths and to a vehicle electrical system which is set up to carry out the method. It is provided that a diagnosis is performed with a component that is assigned to several of the vehicle electrical system paths.

Description

The invention relates to a method for monitoring a vehicle electrical system and such a vehicle electrical system. The electrical system is provided in particular for a motor vehicle.

State of the art

Under an electrical system is to be understood in the automotive use, the totality of all electrical components in a motor vehicle. Thus, this includes both electrical consumers and supply sources, such as batteries. In the motor vehicle care must be taken to ensure that electrical energy is available in such a way that the motor vehicle can be started at any time and that sufficient power is available during operation. But even when parked, electrical consumers should still be operable for a reasonable period of time, without a subsequent start being impaired.

It should be noted that due to the increasing electrification of units and the introduction of new driving functions, the requirement for the reliability of the electrical energy supply in the motor vehicle steadily increases. Furthermore, it must be taken into account that, in the future, highly non-driving activities should be permitted to a limited extent in the case of highly automated driving. A sensory, regulatory, mechanical and energetic fallback by the driver in this case is limited.

Under a highly automatic driving, which is also referred to as highly automated driving, an intermediate step between an assisted driving in which the driver is assisted by assistance systems, and an autonomous driving in which the vehicle drives automatically and without the driver's intervention, to understand. In this, the vehicle has its own intelligence, which could plan ahead and take over the driving task, at least in most driving situations. Therefore, in a highly automatic driving the electrical supply has not previously known in the motor vehicle safety relevance.

Today's conventional 14 V electrical system with only one generator and only one battery can no longer meet the increased demands on the reliability of the electrical supply sufficiently. As an example, mention is made of sailing with the internal combustion engine switched off. During the sailing phase, the generator is no longer available as an energy generator. The failure of the battery in the sailing phase therefore leads to failure of the entire electrical supply in the vehicle. For this reason, 14 V electrical systems with two batteries, so-called 2-battery systems, are currently being discussed by car manufacturers and suppliers of sails.

On-board network topologies for increased reliability on the basis of a 14 V on-board network are known, in which scalable and modular on-board network topologies for supplying safety-relevant electrical consumers are realized. In these consumers are divided into consumer groups with different security relevance, in principle, a two-channel electrical supply for redundant, security-relevant consumers and a fault-tolerant supply for simply existing security-relevant consumers are provided.

In addition to the further development of the 14 V electrical system, car manufacturers are planning to introduce the 48 V / 14 V vehicle electrical system. This 48 V / 14 V electrical system is used in addition to the supply of high-power consumers as entry-level hybridization.

In the publication DE 198 55 245 B4 is described a redundant power supply for electrical loads in a vehicle electrical system. In this case, existing consumers are supplied redundantly from two sub-board networks with different voltage, including a supply of two separate voltage branches is provided.

From the publication DE 10 2006 010 713 B4 is a wiring system for a vehicle with at least one safety-relevant consumer known. In this case, a simply existing security-relevant consumer is supplied redundantly from two subnetworks, a primary network and a secondary network.

Disclosure of the invention

Against this background, a method with the features of claim 1 and an arrangement according to claim 10 are presented. Embodiments result from the dependent claims and the description.

It is thus considered a vehicle electrical system that includes several sub-electrical systems, which are also referred to herein as vehicle electrical system paths. In addition, a base board network may be provided. In the electrical system now components, such as, consumers, DC-DC converters, etc., are provided. These components may be associated with one or more or even all of the vehicle electrical system paths. This means, for example, that the component is provided in several of the vehicle electrical system paths or couples them together. Thus, in particular safety-related consumers can be constructed redundantly, ie they are, for example, provided twice, with both consumers each alone the can fulfill assigned function. This means that a consumer is distributed over two channels or vehicle electrical system paths.

Such a consumer can now carry out a diagnosis in both vehicle electrical system paths and compare the results determined in the diagnoses with each other. In this way, a failure, for example. Under or overvoltage, or impairment of one of the two electrical system paths are detected and it may be initiated countermeasures.

In addition to particularly safety-relevant, redundantly provided consumers, it is also possible to use coupling elements, for example DC-DC converters, arranged in the electrical system, since these vehicle electrical system paths, between which these are arranged, can monitor. If a coupling element is connected between an on-board network path A and an on-board network path B, then it is spoken here that the coupling element is provided in both vehicle network paths.

With the presented method it is achieved to diagnose the condition of several vehicle electrical system channels and to communicate this status to other consumers or actuators. Thus, in the case of a multichannel vehicle electrical system, a higher-level diagnostic instance is available that detects the state of the safety-relevant vehicle electrical system channels.

The diagnosis may, for example, show that a vehicle electrical system path has been impaired or even failed. Furthermore, unwanted galvanic couplings, for example. Between two electrical system paths, can be detected.

It should be noted that in particular in electric vehicles and hybrid vehicles electrical systems can be used in which on the high-voltage side no generator, but an electric machine or a battery can be provided.

Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawings.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the particular combination indicated, but also in other combinations or in isolation, without departing from the scope of the present invention.

Brief description of the drawings

1 shows an embodiment of a vehicle electrical system.

2 shows a further embodiment of a vehicle electrical system.

3 shows a simplified representation of the structure of a consumer.

4 shows an embodiment of a safety-related consumer in a simplified representation.

Embodiments of the invention

The invention is schematically illustrated by means of embodiments in the drawings and will be described in detail below with reference to the drawings.

1 and 2 show exemplary and simplified topologies of on-board networks, as used, for example, in motor vehicles.

1 shows a wiring system, the whole with the reference number 10 is designated. This includes a base board network 12 with a starter 14 , a generator 16 , a battery 18 and a consumer R3 20 , Furthermore, a first coupling element 22 , For example, a DC-DC converter, a first battery 24 and a first consumer R1 26 and a second coupling element 28 , For example, a DC-DC converter, a second battery 30 and a second consumer 32 intended.

It is in this case the base board network 12 with the non-safety-related consumption R3 20 and additionally a first electrical system path 34 and a second electrical system path 36 provided, each with its own coupling element 22 respectively. 28 are coupled and have their own battery 24 respectively. 30 or an electrical storage as well as safety-relevant, redundant consumers R1 26 or R2 32 feature. Consumers R1 26 and R2 32 are intended to perform the same function.

2 shows a wiring system, the whole with the reference number 40 is designated. This includes a base board network 42 with a starter 44 , a generator 46 , a battery 48 and a consumer 50 , Furthermore, a coupling element 52 , a first battery 54 , a first consumer R1 56 and a second consumer 58 intended.

2 shows a variant of the embodiment 1 with a safety-related vehicle electrical system path 60 with the battery 54 and the first consumer 56 , which can also represent a consumer group, which via the coupling element 52 from the base board network 42 decoupled and thus independent of this. A second safety-relevant wiring system path 62 with the second consumer R2, the possibly given by a consumer group, is directly to the base board network 42 connected.

Both in 1 and 2 The topologies shown have in common that there is a group of security-relevant consumers that are redundantly designed and distributed to two separate channels. These are referred to herein as R1 and R2. In the case of highly automatic driving, these are, for example, the brake and the steering, which must be available redundantly.

This ensures that if one of the on-board power supply channels or the channel fails, the other is still available. However, it is of particular importance to be able to detect the failure of a channel and to decouple the defective channel from the functioning electrical system. This is where the proposed process comes in.

In today's on-board networks, the recording of the on-board network status is distributed among the individual components. For example, the battery sensor of the consumer, for example the ESP or the electric steering, measures the vehicle electrical system voltage. However, there is no superordinate component that can detect the state of both channels, for example in the case of two-channel systems.

An example of a safety-related redundant consumer is simplified in 3 to see which one with the reference number 80 is designated. In this all elements including energy supply and communication are doubled. This means that if one channel fails, the other channel alone can ensure safe operation.

The illustration shows a first signal electronics 82 , a second signal electronics 84 , a first main controller 86 , a second main controller 88 , a first power amplifier 90 , a second amplifier 92 , a first engine 94 and a second engine 96 , Furthermore, with double arrows, a first communication 98 , a second communication 100 as well as an internal communication line 102 clarified. Arrows show a first connection 104 to a first electrical system path and a second connection 106 to a second electrical system path. The illustration shows components of a control unit 110 and an engine 112 marked with borders.

The in 3 shown consumer 80 could be a steering system or braking system, ie the engine 112 controls a safety-relevant system. In this redundant consumer 80 are both the signal electronics 82 respectively. 84 , the main controller 86 respectively. 88 , the power amplifiers or output stages 90 respectively. 92 and the engine 112 duplicated. Also the connections 104 respectively. 106 to the on-board network paths and the communication 98 respectively. 100 are provided twice. Thus, in case of failure of a component or a vehicle electrical system or channel in one half, the other half redundant assume the function.

The boxes marked above 82 . 86 . 90 and 94 put one of the consumers from the group R1 in 1 respectively. 2 The boxes below are shown 84 . 88 . 92 and 96 represent a consumer from the group R2. Internal are the two parts 116 . 118 via the internal communication line 102 connected with each other. The two parts 116 . 118 are thus parts 116 . 118 a component in the electrical system, in this case parts 116 . 118 of the redundant consumer 80 ,

• 1. Einen Verbraucher aus der Gruppe der redundant vorhandenen Verbraucher (R1 und R2 genannt) für die Erkennung des Bordnetzzustands zu nutzen, da diese Verbraucher durch seine Teile auf beiden Bordnetzkanälen vorhanden sind und damit die Spannungsqualität der beiden Kanäle vergleichen können. Im konkreten Beispiel könnte der in 3 genannte redundante Verbraucher den ersten Bordnetzpfad und den zweiten Bordnetzpfad überwachen und die Diagnoseergebnisse über die interne Kommunikationsleitung teilen. Ist die Spannungsqualität im ersten Bordnetzpfad 1 schlechter als im Bordnetzpfad 2, würde der Verbraucher R1 oben abschalten und der Verbraucher R2 unten die Funktion übernehmen.
• 2. Den bzw. die Koppelelemente, bspw. Gleichspannungswandler, für die Diagnose der Teilnetze und das Basisbordnetzes zu nutzen. Dies bedeutet, dass bspw. in 2 das Koppelelement den Zustand des Basisbordnetzes und des sicherheitsrelevanten Teilnetzes überwachen und vergleichen kann. Im Fehlerfall auf der Seite des Basisbordnetzes kann somit der Gleichspannungswandler das sicherheitsrelevante Bordnetz mit dem Verbraucher R1 vom Basisbordnetz abkoppeln. Somit würde die Gruppe der sicherheitsrelevanten Verbraucher R1 aus dem Speicher B1 versorgt.

In the presented method, it is now provided that a plurality of vehicle electrical network paths or subnetworks are monitored by an on-board network component which is connected to a plurality of subnetworks. For this purpose, two basic embodiments are conceivable:

• 1. To use a consumer from the group of redundant existing consumers (R1 and R2 called) for the detection of the electrical system state, since these consumers are present through its parts on both electrical systems channels and thus can compare the voltage quality of the two channels. In the concrete example, the in 3 said redundant consumers monitor the first electrical system path and the second electrical system path and share the diagnostic results via the internal communication line. If the voltage quality in the first vehicle electrical system path 1 is worse than in the vehicle electrical system path 2, the consumer R1 would switch off at the top and the consumer R2 below would take over the function.
• 2. Use the coupling element (s), for example DC-DC converter, for the diagnosis of the subnetworks and the base on-board network. This means that, for example, in 2 the coupling element can monitor and compare the state of the base on-board network and of the safety-relevant subnetwork. In the event of a fault on the side of the base-board network, the DC-DC converter can thus decouple the safety-relevant vehicle electrical system with the consumer R1 from the base vehicle electrical system. Thus, the group of safety-related consumers R1 would be supplied from the memory B1.

An advantage of the described method is that existing components in the electrical system are used for monitoring the subnetwork, in which they are functionally expanded. As a result, the integration effort in the wiring harness is reduced for the OEM (original equipment manufacturer) and the components have a multiple benefit or unique selling point feature.

4 shows the example of a consumer, the reference numeral 120 is designated, the necessary changes to the control unit.

The illustration shows a first signal electronics 122 , a second signal electronics 124 , a first main controller 126 , a second main controller 128 , a first power amplifier 130 , a second amplifier 132 , a first engine 134 and a second engine 136 , Furthermore, with double arrows, a first communication 138 to the state of a first electrical system path, a second communication 140 to the state of a second on-board network path and an internal communication line 142 clarified for the comparison of the states of the vehicle electrical system paths. Arrows branch a first connection 144 to a first electrical system path and a second connection 146 to a second electrical system path. The illustration shows components of a control unit 150 and an engine 152 marked with borders. references 156 and 158 designate parts of the redundant load 120 ,

The following steps are now provided:
The input voltage of the respective vehicle electrical system paths is measured and by the respective signal electronics 122 above or 124 read in below. The voltage measurement can be done in a known manner. On the basis of various diagnostic methods, it is evaluated whether the corresponding on-board network path has failed or has been degraded. Furthermore, a coupling between two channels or the coupling of a channel to ground can be determined.

The diagnosis result can be made via the centrally arranged communication line 142 be communicated to the other part. It depends on which part, above or below, takes over the further function.

• • Ausfall eines Kanals: – Statische Unterspannung, z. B. kleiner 9 V – Statische Überspannung, z. B. größer 16 V – Dynamische Unterspannung, z. B. 10 ms kleiner 6 V – Dynamische Überspannung, z. B. 10 ms größer 19 V
• • Zeitliche oder dynamische Begrenzung eines oder beider Kanäle: – Zeitbegrenzung: Spannung dauerhaft bei 12 V (Ausfall Gleichspannungswandler)
• • Ungewollte galvanische Kopplung der Kanäle untereinander: – Sind die Spannung Kanal 1 = Kanal 2, auch bei Aufschaltung von Verbrauchern oder wenn einer der Wandler aktiv und der andere inaktiv ist, können die Kanäle durch einen Isolationsfehler galvanisch verbunden sein. Dies muss erkannt werden, um den Fehler ggf. zu kapseln.
• • Ungewollte Kopplung eines/beider Kanäle mit dem Basisbordnetz: – Die Galvanische Kopplung mit dem Basisbordnetz kann bei der Topologie im 1 nur über den jeweiligen Gleichspannungswandler erkannt werden – Bei der in 2 gezeigten Topologie kann die galvanische Kopplung zwischen Basisbordnetz und dem sicherheitsrelevanten Teilnetz sowohl über den Gleichspannungswandler als auch über einen redundanten sicherheitsrelevanten Verbraucher erkannt werden.

In this way, the following errors can be detected:

• • Failure of a channel: - static undervoltage, eg. B. less than 9 V - Static overvoltage, z. B. greater 16 V - Dynamic undervoltage, z. B. 10 ms less than 6 V - dynamic overvoltage, z. B. 10 ms greater 19 V
• • Time or dynamic limitation of one or both channels: - Time limit: Voltage permanently at 12 V (DC-DC converter failure)
• • Unintentional galvanic coupling of the channels with each other: - If the voltage is channel 1 = channel 2, even if consumers are connected or if one of the converters is active and the other is inactive, the channels may be galvanically connected due to an insulation fault. This must be recognized in order to encapsulate the error if necessary.
• • Unintentional coupling of one / both channels to the base on-board network: - The galvanic coupling with the base on-board network can be used for the topology in the 1 can only be detected via the respective DC-DC converter - In 2 As shown, the galvanic coupling between the base on-board network and the safety-relevant subnet can be recognized both via the DC-DC converter and via a redundant safety-relevant consumer.

Here too it can be checked whether the condition voltage channel 1 = voltage channel 2 is permanently fulfilled.

Finally, the electrical system status could other, for. B. safety-relevant, consumers, a higher-level energy management, other on-board network participants, such as. Coupling elements, memory, sources, or the driver to be notified. Draus other measures can be derived, for example, the opening of coupling elements, increasing the power of energy sources, the connection or disconnection of other electrical system loads.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely 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.

Cited patent literature

• DE 19855245 B4 [0008]
• DE 102006010713 B4 [0009]

Claims (11)

Method for operating a vehicle electrical system ( 10 . 40 ), which has at least two electrical systems ( 34 . 36 . 60 . 62 ), wherein in the electrical system ( 10 . 40 ) are provided, wherein a diagnosis is performed with at least one of the components, the plurality of Bordnetzpfade ( 34 . 36 . 60 . 62 ) assigned. Method according to Claim 1, in which the diagnosis is carried out with a component which in each case comprises at least one part ( 116 . 118 . 156 . 158 ) in different vehicle electrical system paths ( 34 . 36 . 60 . 62 ), wherein a communication via an internal communication line ( 102 . 142 ) between the parts. Method according to claim 2, in which as components consumers ( 26 . 32 . 56 . 58 . 80 . 120 ), wherein the diagnosis is performed with at least one of the consumers, which in several of the vehicle electrical system paths ( 34 . 36 . 60 . 62 ) is provided. Method according to claim 3, in which the consumers ( 26 . 32 . 56 . 58 . 80 . 120 ) are assigned to different security levels. Method according to Claim 1, in which at least one coupling element ( 22 . 28 . 52 ) between two electrical system paths ( 34 . 36 . 60 . 62 ), wherein the diagnosis with at least one of the at least one coupling element ( 22 . 28 . 52 ) carried out in several of the vehicle electrical system paths ( 34 . 36 . 60 . 62 ) is provided. Method according to one of claims 1 to 5, wherein the diagnosis based on the measurement of input voltages of the vehicle electrical system paths ( 34 . 36 . 60 . 62 ), which of the vehicle electrical system paths ( 34 . 36 . 60 . 62 ) becomes active. Method according to one of claims 1 to 6, which is used to a temporal or dynamic limitation of one of the vehicle electrical system paths ( 34 . 36 . 60 . 62 ) to recognize. Method according to one of claims 1 to 7, which is used to a failure by under- or overvoltage of one of the vehicle electrical system paths ( 34 . 36 . 60 . 62 ) to recognize.  Method according to one of claims 1 to 8, which is used to detect an unwanted galvanic coupling. Vehicle electrical system for a motor vehicle, which is set up in particular for carrying out a method according to one of claims 1 to 9, with at least two vehicle electrical system paths ( 34 . 36 . 60 . 62 ), whereby in the electrical system ( 10 . 40 ) are provided, wherein at least one of the components, the plurality of vehicle electrical system paths ( 34 . 36 . 60 . 62 ) is arranged to perform a diagnosis. Vehicle electrical system according to Claim 10, in which the diagnosis is to be carried out with a component which in each case has at least one part ( 116 . 118 . 156 . 158 ) in different vehicle electrical system paths ( 34 . 36 . 60 . 62 ), wherein a communication via an internal communication line ( 102 . 142 ) between the parts.

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