CN107110896B

CN107110896B - Method for monitoring a vehicle electrical system

Info

Publication number: CN107110896B
Application number: CN201580072861.3A
Authority: CN
Inventors: M.霍恩; C.博内
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2015-01-08
Filing date: 2015-11-12
Publication date: 2020-12-01
Anticipated expiration: 2035-11-12
Also published as: DE102015200121A1; CN107110896A; EP3243084A1; WO2016110352A1

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 for carrying out the method. It is provided that the diagnosis is carried out with components which are assigned to a plurality of the on-board electrical system paths.

Description

Method for monitoring a vehicle electrical system

Technical Field

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

Background

"on-board power system" in the use of a motor vehicle is a generic term for all electrical components in the motor vehicle. Thus, not only electrical loads but also power supply sources, such as for example batteries, are included therein. In motor vehicles, it is to be noted that electrical energy can be available in such a way that the motor vehicle can be started at any time and that there is a sufficient supply of current during operation. However, in the stopped state, the electrical load should also be able to operate for a suitable time interval without impairing the subsequent start-up.

It should be noted that the demand for reliability of the energy supply in motor vehicles is constantly increasing due to the increasing degree of electrification of the assembly and the adoption of new driving functions. Furthermore, it should be taken into account that in the future (fahrfremd) activities outside driving at a high degree of automation should be allowed to a limited extent. In this case, the sensor, control, mechanical and energy backup level (ruckfillebene) caused by the driver is also only present to a limited extent.

"highly automated driving", also referred to as highly automated driving, refers to an intermediate step between assisted driving, in which the driver is supported by an assistance system, and autonomous driving, in which the vehicle is driven automatically and without the influence of the driver. For autonomous driving, the vehicle has its own intelligent system, which can be planned in advance and can undertake driving tasks at least in most driving situations. Therefore, the power supply device has a safety concern that has not been recognized in the past in the motor vehicle when highly automated driving is performed.

The conventional 14V on-board electrical systems of today, which have only one generator and only one battery, no longer meet the requirements of increased reliability of the power supply to a sufficient extent. As an example, a coasting of the combustion motor with switching off is mentioned here. During the coasting phase, the generator is no longer available as an energy generator. In the coasting phase, a failure of the battery therefore leads to a failure of the entire power supply in the motor vehicle. For this reason, for automobile manufacturers and suppliers, 14V onboard power systems, so-called dual-battery onboard power systems, which currently have two batteries, are being investigated for coasting.

Vehicle electrical system topologies based on a 14V vehicle electrical system for increased reliability are known, for which an expandable (Skalierbear) and modular vehicle electrical system topology is implemented for supplying electrical loads related to safety. For these on-board power supply system topologies, the loads are divided into load groups with different safety dependencies, wherein in principle a dual-channel supply is provided for redundant safety-related loads and a fault-tolerant (fehlertolerant) supply is provided for single-present safety-related loads.

In addition to the further development of the 14V on-board electrical system, the adoption of 48V/14V on-board electrical systems is planned by the automobile manufacturers. This 48V/14V on-board power system is used as a mild hybrid system (Einstiegs-hybrid) in addition to the power supply for high-power loads.

A redundant voltage supply device for an electrical load in a vehicle electrical system is described in german patent application DE 19855245B 4. In this case, two sub-onboard power networks with different voltages are used to supply the existing loads, for which purpose a power supply device is provided which is formed by two separate voltage branches.

Published german patent application DE 102006010713B 4 discloses an on-board electrical system for a vehicle having at least one safety-relevant load. In this case, the two sub-networks, i.e. the primary network and the secondary network, redundantly supply the single-present safety-relevant load.

Disclosure of Invention

To this end, the invention proposes a method for operating an onboard electrical system, which includes at least two onboard electrical system paths, a plurality of components being provided in the onboard electrical system, wherein a diagnosis is carried out with at least one of the components, which is assigned to a plurality of the onboard electrical system paths. Furthermore, an onboard power supply system for a motor vehicle is proposed, which is designed in particular for carrying out the method and has at least two onboard power supply system paths, a plurality of components being provided in the onboard power supply system, at least one of the components being designed for carrying out the diagnosis, the at least one component being assigned to a plurality of the onboard power supply system paths.

A study is therefore made of an on-board electrical system which comprises a plurality of sub-on-board electrical systems, which are also referred to herein as on-board electrical system paths. Furthermore, a basic onboard power supply system can be provided. Components, such as, for example, loads, dc converters, etc., are now provided in the onboard electrical system. These components can be assigned to one or more of the onboard power network paths or even all onboard power network paths. This means, for example, that the components are arranged in a plurality of the on-board electrical system paths or are coupled to one another. In particular, safety-relevant loads can thus be designed redundantly, i.e., they are provided, for example, in duplicate, wherein both loads can each perform their assigned function individually. This means that the load is distributed over two channels or on-board electrical system paths.

Such loads can now carry out a diagnosis in the two on-board power supply system paths and compare the results obtained during the diagnosis with one another. In this way, malfunctions, for example due to undervoltage (Unterspannung) or overvoltage (Ü berspannung), or damage to one of the two onboard power supply systems paths can be detected and countermeasures can be taken if necessary.

In addition to the redundantly provided loads, which are especially safety-relevant, coupling elements, such as direct-current voltage converters, which are arranged in the vehicle electrical system can also be considered, since they can monitor the vehicle electrical system paths between which they are arranged. If a coupling element is connected between the on-board power supply system path a and the on-board power supply system path B, it is said that the coupling element is arranged in both on-board power supply system paths.

This is achieved with the described method: the status of a plurality of on-board power supply system channels is diagnosed and is communicated to further loads or controllers. In this way, a higher-level diagnostic unit is present for the multichannel vehicle electrical system, which identifies the state of the safety-relevant vehicle electrical system channels.

The diagnosis can, for example, indicate that the on-board electrical system path is impaired or even malfunctioning. Furthermore, for example, unintentional galvanic couplings (galvanosche Kopplung) between the two onboard power supply lines can be detected.

It should be noted that, in particular for electric or hybrid vehicles, an on-board electrical system can be used, for which no generator can be provided on the high-voltage side, but rather a motor or a battery can be provided.

Further advantages and embodiments of the invention emerge from the description and the drawing.

It is clear that the features mentioned above and those yet to be explained below can be used not only in the respectively specified combination but also in other combinations or individually without departing from the scope of the invention.

Drawings

FIG. 1 illustrates one embodiment of an onboard power grid;

FIG. 2 illustrates another embodiment of an onboard power grid;

fig. 3 shows the configuration of the load in a simplified illustration; and is

Fig. 4 shows an embodiment of a safety-relevant load in a simplified illustration.

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

Detailed Description

Fig. 1 and 2 show exemplary and simplified topologies of an on-board electrical system, such as is used in a motor vehicle.

Fig. 1 shows an onboard electrical system, which is designated by reference numeral 10. The vehicle electrical system includes a base vehicle electrical system 12, which in turn has a starter 14, a generator 16, a battery 18 and a load R320. Furthermore, a first coupling element 22, such as a dc voltage converter, a first battery 24 and a first load R126, and a second coupling element 28, such as a dc voltage converter, a second battery 30 and a second load 32, are provided.

In this case, a base onboard electrical system 12 with non-safety-relevant loads R320 is provided, and additionally a first onboard electrical network path 34 and a second onboard electrical network path 36 are provided, which are coupled via their

respective coupling elements

22 and 28 and have their

own battery

24 and 30 or electrical storage and safety-relevant, redundant loads R126 and R232, respectively. The loads R126 and R232 are arranged to perform the same function.

Fig. 2 shows an onboard electrical system, which is designated in its entirety by reference numeral 40. The vehicle electrical system includes a base vehicle electrical system 42 having a starter 44, a generator 46, a battery 48, and a load 50. Furthermore, a coupling element 52, a first battery 54, a first load R156 and a second load 58 are provided.

Fig. 2 shows a variant of the embodiment of fig. 1, which has a safety-relevant on-board electrical system path 60, which has the battery 54 and the first load 56, which can also represent a load group that is decoupled from the base on-board electrical system 42 by means of the coupling element 52 and is thus independent of the latter. The safety-relevant second onboard power supply system 62, which is connected directly to the base onboard power supply system 42, has a second load R2, which is generated, if necessary, by means of a load group.

The two topologies shown in fig. 1 and 2 have in common: there are groups of safety-relevant loads which are designed redundantly and are distributed over two separate channels. The loads are referred to herein as R1 and R2. In the case of highly automated driving, these are, for example, brakes and steering mechanisms, which must be present redundantly.

This ensures that, in the event of a failure of one on-board electrical system path or channel, a further on-board electrical system path or channel can continue to be available. In this case, however, it is of particular significance to be able to detect a malfunction of a channel and to disconnect a defective channel from a properly functioning vehicle electrical system. The method described is started here.

In modern vehicle electrical systems, the detection of the vehicle electrical system state is distributed to the individual components. The load, for example an ESP or a battery sensor of an electric steering system, for example, measures the vehicle electrical system voltage. However, a higher-level component, which is able to detect the state of two channels, for example in a dual-channel system, is missing.

An example of a load for safety-relevant redundancy can be seen in simplified form in fig. 3, which load is designated by the reference numeral 80. All components, including the energy supply and the communication mechanism, are duplicated for the load. This means that in the event of a failure of one channel, the other channel can ensure safe operation on its own.

The illustration shows first signal electronics 82, second signal electronics 84, first master controller 86, second master controller 88, first output stage 90, second output stage 92, first motor 94, and second motor 96. The first communication means 98, the second communication means 100, and the internal communication line 102 are indicated by double arrows. The arrows show a first connection 104 to a first on-board electrical network path and a second connection 106 to a second on-board electrical network path. In the illustration, components of the controller 110 and the motor 112 are identified by a bezel.

The load 80 shown in fig. 3 may be a steering system or a braking system, i.e. the motor 112 controls safety-relevant systems. For this redundantly designed load 80, not only the

signal electronics

82 and 84, the

master controller

86 and 88, the output stage or

power output stage

90 and 92, but also the motor 112 are present in duplicate. The

connections

104 and 106 to the on-board electrical system path and the communication means 98 and 100 are also doubly provided. In this way, in the event of a failure of a module or a vehicle electrical system path or channel in one half, the respective other half can redundantly assume the function.

The

boxes

82, 86, 90 and 94 illustrated above represent one of the loads from the set R1 in fig. 1 or 2, and the

boxes

84, 88, 92 and 96 illustrated below represent the loads from the set R2. Internally, the two

components

116, 118 are connected to each other by means of the internal communication line 102. The two

components

116, 118 are thus

components

116, 118 of a component in the onboard power supply system, in this

case components

116, 118 of the redundant load 80.

With the method described, it is now provided that a plurality of onboard power system paths or sub-power systems are monitored by an onboard power system component connected to a plurality of sub-power systems. Two principle embodiments can be considered for this purpose:

1. loads from groups of redundantly present loads (referred to as R1 and R2) are used to detect the vehicle electrical system state, since these loads are present via their components on two vehicle electrical system channels and can thus compare the voltage quality of the two channels. In a specific example, the redundant loads mentioned in fig. 3 are able to monitor the first and second on-board power supply system paths and to share the diagnosis results via internal communication lines. If the voltage quality in the first vehicle electrical system path 1 is worse than in the vehicle electrical system path 2, the upper load R1 is switched off and the lower load R2 assumes the function;

2. a coupling element or a plurality of coupling elements, such as dc voltage converters, are used for diagnosing the sub-and base on-board electrical systems. This means that, for example, in fig. 2, the coupling element can monitor and compare the state of the base on-board electrical system and of the safety-relevant sub-system. In the event of a fault on one side of the base on-board electrical system, the dc voltage converter can thus disconnect the safety-relevant on-board electrical system with the load R1 from the base on-board electrical system. Thereby, the group of safety-relevant loads R1 is supplied by the storage B1.

The method described has the advantage that the components present in the onboard power supply system are used for monitoring the sub-power supply system, and the method comprises: the components are functionally expanded. Thereby, the integration overhead in the cable harness is reduced for the OEM (original equipment manufacturer) and the assembly has multiple uses or proprietary features.

Fig. 4 shows the necessary changes made on the controller on the example of the load indicated by reference numeral 120.

The illustration shows first signal electronics 122, second signal electronics 124, first master controller 126, second master controller 128, first output stage 130, second output stage 132, first motor 134, and second motor 136. The double arrows indicate a first communication means 138 for the state of the first onboard power supply system path, a second communication means 140 for the state of the second onboard power supply system path, and an internal communication line 142 for comparing the states of the onboard power supply system paths. The arrows show a first connection 144 to a first on-board electrical network path and a second connection 146 to a second on-board electrical network path. In the illustration, the components of the controller 150 and the motor 152 are identified by a bezel.

Reference numerals

156 and 158 denote redundant components of the load 120.

Now the following steps are set:

the input voltage of the respective onboard power supply system path is measured and read in by the respective upper or

lower signal electronics

122 or 124. The voltage measurement can be carried out in a manner known per se. Evaluation was carried out by means of different diagnostic methods: whether the respective on-board electrical system path is malfunctioning or degraded. Furthermore, a coupling between the two channels or a coupling of the channel to the ground can be determined.

The diagnostic result can be notified to the respective further components by means of the centrally arranged communication line 142. This depends on: which component, i.e. the upper or the lower component, assumes the further function.

In this way, the following faults can be identified:

failure of the channel:

static undervoltage, such as less than 9V;

static overpressure, such as greater than 16V;

dynamic under-voltage, such as 10ms less than 6V;

dynamic overpressure, such as 10ms greater than 19V;

time bounds or dynamic bounds for one or two channels:

-a time limit: voltage sustained at 12V (failure of DC voltage converter)

Unintentional galvanic coupling of the channels to one another:

if the voltage is channel 1= channel 2 even when the load is switched on or when one of the converters is active and the other converter is inactive, the channels may be galvanically connected due to an insulation fault. This point must be identified for encapsulating the fault if necessary (kapseln);

unintentional coupling of one/both channels to the base onboard electrical system:

the galvanic coupling to the base onboard power supply system can be recognized only by the respective dc voltage converter for the topology in fig. 1;

for the topology shown in fig. 2, the galvanic coupling between the base on-board electrical system and the safety-relevant sub-system can be recognized both by the dc voltage converter and by redundant safety-relevant loads.

Here too it can be checked: channel 1 voltage = channel 2 voltage the condition is continuously fulfilled or not.

Finally, the vehicle electrical system state can be communicated to further, for example safety-relevant loads, higher-level energy management systems, further vehicle electrical system participants, such as, for example, coupling elements, storage devices, power sources or drivers. From this, further measures can be derived, such as the disconnection of the coupling element, the increase in the output of the energy source, the switching on or off of further onboard electrical system loads.

Claims

1. Method for operating an onboard electrical system (10, 40) comprising at least two onboard electrical system paths (34, 36, 60, 62), wherein a plurality of components are provided in the onboard electrical system (10, 40), wherein a diagnosis is carried out with at least one of the components which is assigned to a plurality of the onboard electrical system paths (34, 36, 60, 62),

wherein as an assembly at least one coupling element (22, 28, 52) is arranged between two on-board electrical system paths (34, 36, 60, 62), wherein the diagnosis is carried out with at least one of the at least one coupling element (22, 28, 52) which is arranged in a plurality of the on-board electrical system paths (34, 36, 60, 62).

2. The method according to claim 1, wherein the diagnosis is carried out on the basis of a measurement of an input voltage of the on-board electrical system path (34, 36, 60, 62): which of the onboard power supply lines (34, 36, 60, 62) is active.

3. Method according to claim 1 or 2, which is used to identify a time limit or a dynamic limit of one of the onboard power supply system paths (34, 36, 60, 62).

4. The method according to claim 1 or 2, wherein the method is used to detect a malfunction due to an undervoltage or an overvoltage of one of the on-board electrical system paths (34, 36, 60, 62).

5. The method according to claim 1 or 2, which is used to detect unintentional galvanic couplings.

6. On-board electrical system for a motor vehicle, in particular set up for carrying out the method according to one of claims 1 to 5, having at least two on-board electrical system paths (34, 36, 60, 62), wherein a plurality of components are provided in the on-board electrical system (10, 40), wherein at least one of the components is set up for carrying out a diagnosis, which is assigned to a plurality of the on-board electrical system paths (34, 36, 60, 62).

7. The on-board electrical system as claimed in claim 6, wherein the diagnosis can be carried out with a module which comprises in each case at least one component (116, 118, 156, 158) of the different on-board electrical system paths (34, 36, 60, 62), wherein the communication takes place between the components via internal communication lines (102, 142).