DE202005011235U1 - Device for overload protection of a supply line for an electrical load in a motor vehicle - Google Patents

Abstract

contraption for overload protection a supply line (12A) for an electric load in a motor vehicle, in particular a window motor (16), wherein for controlling the electrical load (16) a control unit (10) with a monitoring device (20A) and the monitoring device (20A) is designed such that on the basis of operating data (B) the supply line (12A) is monitored for overload and when detected on overload a disconnection of the supply line (12A) is caused.

Description

The The invention relates to a device for overload protection of a supply line for an electrical Last, especially for a power window motor, in a motor vehicle.

Of the Electric window motor is usually connected to a hierarchical structured on-board network structure connected. This has several Distribution levels for the distribution of the provided by the motor vehicle battery Energy up. To protect the wiring system cables against overload due to an overload current Suitable fuses, usually fuses, are provided. In motor vehicle are this usually several fuse boxes arranged, arranged in each case a plurality of securing elements are. According to the hierarchical structure of the on-board network is over a each fuse element in each case a partial area or a lower part area secured by the vehicle electrical system. The supply lines of several end consumers are therefore over usually as Fuse trained common fuse element against overload hedged.

Of the Invention is based on the object, a reliable protection a supply line of a load in a motor vehicle against overload to ensure.

The The object is achieved by a device according to claim 1. Thereafter, for overload protection the supply line in particular for a window regulator motor monitoring device provided, which on the basis of the current operating data of the Supply line monitors this for overload and causes disconnection of the supply line, if necessary. By the disconnection of the supply line becomes this in particular over its whole length without power. The monitoring device is here in particular for designed a reversible disconnection or switching of the supply line, so after discontinuing the for the overload responsible disorder the supply line can be switched on again.

One Essential point is in the determination of the actual current operating data - either directly or indirectly - the To see supply line. As a result, the respective supply line individually monitored and a decentralized overload protection based on the individual supply line is realized. So it will be on the last hierarchical level within a wiring system - and so very sensitive - the Decision made whether an overload is present.

at the usual Vehicle electrical system structure, in which several supply lines via a are hedged common fuse element, it is for safety reasons establish not possible, one one of the jointly secured supply lines to the actual Current consumption of the end user, since the supply line, in particular their cross-section, by the security value the fuse element is determined. The use of a common Fuse element with smaller fuse value is due to the common supply of several end consumers.

The Supply line-specific monitoring has the particular advantage that the cross section of the Supply line without loss of security to the actual Power consumption of the end user can be adjusted. Especially is through this measure allows the use of new line technologies, such as Foil cables or flat cables that save space and weight Have conductor structures with small conductor cross-sections.

The monitoring device is for example an electronic circuit or an electronic module, which is designed such that, in the event of an overcurrent, the flow of current across the Supply line is suppressed. This is generally the supply line from the power supply or from the control electronics of a door control module or at a separation point of the door module to the rest of the vehicle electrical system, e.g. a plug, in particular by means a switch disconnected.

According to one expedient development is a monitoring program as a monitoring device intended. The monitoring program reads the operating data, decides whether an overload exists and causes If necessary, the separation of the supply line. By this measure is therefore a safer on purely program or software technical way and reliable overload protection the supply line achieved without requiring costly and installation space required hardware components are necessary.

By using a software-implemented line protection, the line protection is also very easy and easily adaptable to the current, line or load-specific operating parameters. Thus, further developments, for example, lead to the fact that smaller power window motors are used, easily considered and incorporated into the monitoring program by a suitable parameter setting, without a change to the wiring system is necessary or repercussions to other on-board power supplies are to be feared. The software overload protection therefore makes it possible in a simple manner, even with existing wiring systems Anpas make adjustments.

According to one expedient development is using at least one sensor element the direct determination of the operating data of the supply line intended. Such a sensor element is for example a Shunt resistor or a so-called SenseFET for direct current measurement. As a sensor element is still, for example, a temperature sensor for direct measurement of the temperature of the supply line as a measure of the flow of electricity and as a criterion for an overload intended. Operating parameters of the supply line are therefore for example, the current, the altitude the applied voltage or its current temperature.

In In a preferred embodiment, the monitoring device is such formed that operating data over the supply line connected load is derived and derived therefrom, whether an overload is present. In this embodiment, therefore, in particular an indirect detection the operating data of the supply line on the operating data of the load intended. Since the operating data of the load are often available anyway, are for the extra Implementation of thermal overload protection for the Supply line no additional Hardware components required and provided. The load is particular an electric motor. The operating data of the engine are, for example its current consumption, the applied voltage, its speed etc.

Preferably Furthermore, a sensor system for determining the operating data is provided, from which then the temperature of the supply line as a criterion for an overload is derived.

In In a preferred embodiment, the sensor system is in this case designed such that an engine speed of the component and the supply voltage be recorded and the monitoring program based on the current engine speed, the supply voltage and a stored motor characteristic determines whether an overload is present. Such a configuration is particularly suitable in those systems where there is a so-called excess force limit is provided. In fact, such systems usually already have a Hall sensor integrated for speed measurement, so over the preferred software technology realized line protection only on an already existing Sensors are used needs to be and evaluated only available operating data become.

According to one preferred alternative, the sensor is designed such that the supply voltage and the supply current of the load detected become. Such a configuration is particularly useful controlled drives or in systems with so-called Ripplestromauswertung on. Because with regulated drives is usually a power electronics in the form of a semiconductor circuit breaker used instead of a relay, which has a current measuring output at which the current value is tapped can. Here, too, is for the software technical line protection no excessive additional effort required and it is used on existing components.

Prefers Therefore, the load current by means of a Ripplestromauswertung and / or derived with the help of a Hall sensor. Under ripplestrom becomes common a caused by the control electronics ripple the drive current of the electric motor understood. From the ripple let yourself the current level derive the drive current.

According to one expedient training is next to the line protection as well a thermal overload protection for the Load provided, which also program or software technology is realized. For this purpose, another monitoring program is provided, which likewise monitors this for thermal overload on the basis of operating data of the load. As a result of the software implemented thermal protection eliminates the Necessity of a hardware thermal protection element, such as For example, a bimetal, which usually adds to Costs leads and installation space claimed. In principle, there is the possibility the preferred software implemented and integrated in the control unit Line protection with a separately integrated directly in the window motor Hardware thermal protection element to combine.

Conveniently, form the monitoring program and the further monitoring program a combined program for overload protection of the supply line as well as for the thermal protection of the load. The program is here especially modular. This embodiment is here from the consideration from that both monitoring programs on similar Build algorithms and similar or use the same operating data of the window motor. Overall, this allows a simplified programming.

Preferably, a thermal model of the supply line is used for monitoring the supply line for overload. In this thermal model, relevant line parameters are taken into account, such as line cross section, specific resistance, thermal conductivity, a coefficient for the heat release to the environment, etc., on the basis of this ther In the model, criteria are specified and stored, which are used to decide whether an overload exists or not.

For the decision, whether an overload is present, according to a preferred development on at least one, preferably several, used in a memory stored characteristics. Such Characteristic is, for example, the motor characteristic. The characteristics Here are each specific to the currently realized component combination customized. The component combination here includes the type or Type of supply line and the type of motor used. Out The characteristic can be easily without much computational effort in knowledge a certain operating value of an operating parameter, the values taken from further operating parameters relevant to the decision are, whether an overload is present. In addition to the load-specific operating parameters are here also takes into account further operating parameters of the supply line. Generally, variable operating parameters can be used in which the value of the parameter changes during operation, from fixed operating parameters, where the value of the parameter is independent of the current operating situation is different. Variable operating parameters are for example the engine speed, the supply current, the supply voltage. Fixed operating parameters are, for example, the material of the supply line or their cross-section.

Conveniently, In this case, the characteristic curve gives the relationship between one of the operating parameters the load or the supply line and a temperature of the supply line again. The temperature is therefore considered a decisive criterion for the determination overloaded and it only needs to be read from the characteristic curve whether an overload is already present at a certain value of an operating parameter is present.

to Determining if an overload is present, is supplementary or alternatively in an expedient development resorted to an algorithm, with its help from the operating data of the load and / or the supply line the current load of the supply line is calculated. Of the Algorithm considered Therefore, the underlying thermal model and has as parameters over the Sensor system or the sensor elements measured current operating parameters on. Based on the current measured values for the operating parameters (operating data) then the respective thermal load is calculated.

Instead of or in addition For this purpose, it is preferably provided that one or more threshold values for a or several operating parameters are stored, when they are exceeded on overload is recognized. With this simplified method is no online computing effort required. The thresholds need only once before calculated on the basis of the thermal model or alternatively to have been determined empirically.

Conveniently, is further provided that the monitoring device, in particular the monitoring program, also for checking the Supply line is formed. Under review is understood here, that from the measured operating data conclusions about the current line condition be drawn and from this in the sense of a forward-looking diagnosis statements about the current state of the supply line are derived. For example is fed from a comparison of the fed into the supply line Electricity and that actually Current consumed by the load determines if any leakage currents exist. Generally, comparing the operating data of the supply line with which the load determines if the supply line is faulty is. The review or Diagnosis is for this purpose, for example, directly from the monitoring device carried out. Alternatively, there is also the possibility of correlating the measured operating data store each other in a memory and, for example, at a normal inspection of the motor vehicle read and evaluate.

Preferably is still a temperature sensor provided for detecting the ambient temperature and the ambient temperature is used to determine the temperature of the supply line, So for the decision as to whether an overload is present. Alternatively, preferably, a fixed temperature value for the Ambient temperature specified, in particular the maximum to expected ambient temperature and for the decision on overload is used.

Conveniently, continues to be the number of switching operations of the component per unit time, ie the switching frequency, determined and considered in deciding whether an overload is present.

According to one expedient development is the supply line as a Flat cable, for example, a grid-land line an FFC line (flexible flat cable) or as an FPC (flexible printed circuit) -Leitung trained.

Preferably, the supply line is designed as an FPC line with integrated electronics. That is, in the line is directly, for example, an electronic evaluation circuit and / or an electronic circuit breaker or an electronic fuse element for separating the Supply line from the power supply integrated.

alternative For this purpose, the supply line via a plug to the power supply or a door control unit is connected, wherein an integrated fuse element is provided in the plug, in particular a circuit breaker for disconnecting the supply line.

Preferably is here in the sense of a possible decentralized fuse of the supply line the fuse element outside a fuse box arranged decentrally.

Especially in view of the intended use of new pipeline technologies, For example, foil lines or the like, is in an advantageous Design provided that the actual cable cross-section the supply line is smaller than a line cross section, such as he for the backup value of a central security element required would. The basic structure of the electrical system therefore remains untouched and at the same time is one Supply line used with a reduced cable cross-section, which to the actual expected power consumption of the engine is adjusted.

An embodiment of the invention will be explained in more detail below with reference to the drawing. The 1 to 3 show in schematic and highly simplified block diagram representations alternative embodiments of a partial section of a motor vehicle electrical system.

The sectional electrical system shown comprises in accordance with 1 a central fuse box 2 in which several common security elements 4 for securing wiring systems 6 . 6A are provided against overload. In the embodiment, only a common fuse element 4 hinted that the line 6A of the vehicle electrical system protects against overload. The fuse box 2 itself is in turn by a supply line 8th connected to a higher hierarchical level of the electrical system, for example with a Vorsicherungsdose, which is directly downstream of the motor vehicle battery.

About the line 6A is a control unit 10 connected to the electrical system, from which several supply lines 12 . 12A depart. The supply lines 12 . 12A are therefore common by the common fuse element 4 secured against overload.

The control unit 10 is over the supply line 12A and one in the controller 10 integrated switch 14 with an electric window motor 16 connected. The control unit 10 is usually integrated within a door module of a motor vehicle door and is used to control and supply the integrated components in the door module, such as for controlling the window lift motor or for connecting control elements, for example for the remote controlled opening of the hood, the trunk, other windows motors, etc. The control unit 10 This is usually about a cut or separation point not shown here with the line 6A connected. This interface is usually realized as a plug. Alternative to that in the control unit 10 implemented switch 14 this is arranged downstream of the control unit. The desk 14 is used to disconnect the supply line 12A and thus forms a trained as a circuit breaker fuse element.

The control unit 10 has a combined program 18 in which a first monitoring program 20A and a second monitoring program 20B combined with each other. In the control unit 10 is next to other components not shown here a memory 22 intended. The control unit 10 receives via a first data line 24A Operating data B 'of the window motor 16 , The operating data B 'are the current actual values of operating parameters, such as engine speed, supply voltage, supply current, etc. As shown by the dashed arrow, also operating data B of the supply line 12A recorded and the monitoring program 20A to provide.

For detecting the operating data B 'of the load 16 are one or more suitably trained and sensor elements forming sensor elements 25 intended. In the embodiment, only one sensor element 25 as part of the Fensterhebermo sector 16 shown. The sensor element 25 is, for example, the current output of a semiconductor power switch, which is used in place of a relay. Alternatively, the sensor element 25 a measuring or switching resistor. Also, the sensor element 25 be a Hall sensor for speed measurement. Preferably, this is based on sensor elements 25 which are already used for other functions, so that there is no additional effort for the implementation of the sensor technology.

Via a second data line 24B is the control unit 10 with a temperature sensor 26 connected. This serves to measure the ambient temperature and transmits corresponding temperature data T to the control unit 10 ,

In the embodiment according to 2 is unlike the according to 1 no sensors for detecting the operating data B 'of the load 16 intended. Rather, in this embodiment, with the aid of a further sensor element 28 the operating data B of the supply line 12A recorded directly and the monitoring program 20A made available. In the exemplary embodiment, the further sensor element 28 a shunt resistor for direct current measurement of the supply line 12A fed electricity.

In the embodiment according to 3 is finally also the direct measurement of the over the supply line 12A flowing current provided. The further sensor element 28 is here designed as a so-called SenseFet, which also simultaneously the switch 14 represents over which the supply line 12A is disconnected if necessary. sensor element 28 and fuse element 14 are therefore realized by a single component.

In the embodiment of 3 is still the supply line 12A trained as an FPC line and the SenseFet 28 is implemented on this FPC line as an integrated device. The FPC line is directly to the controller 10 as well as the window regulator motor 16 , for example, via suitable connectors connected.

In the embodiments according to the 2 and 3 In addition, as in the embodiment according to 1 the operating data B 'of the load 16 be used in addition.

Because of the fuse element 4 at the same time several supply lines 12 For safety reasons, without additional measures, the supply line can be protected 12A not be replaced by a supply line designed for smaller currents. The fuse element 4 is to protect the supply lines 12 . 12A For example, designed as a 3A fuse, so has a fuse rating of 3 amps. All hierarchically in the electrical system downstream lines 6A . 12 . 12A passing over the fuse element 4 must be designed for at least a current of 3 amperes, even if the actual expected current consumption of the respective load is significantly lower. Even if such a supply line 12A with a smaller conductor cross-section for the power supply of the window regulator motor 16 would be sufficient. The use of smaller or more advanced window regulator motors 16 therefore conventionally does not allow adjustment of the supply line 12A ,

Order for the supply line 12A To provide an effective overload protection is a software implemented overload protection implemented. This is done with the help of the monitoring program 20A based on the obtained operating data B. B 'and taking into account the temperature data T, the expected temperature of the supply line 12A derived and used as a criterion for the decision whether an overload exists or not. This decision is taken by the monitoring program 20A this back to not shown curves that in memory 22 are stored.

Thus, for example, in a first alternative from the measured engine speed, the measured supply voltage and the motor characteristic to the expected temperature load on the supply line 12A closed back. In a second alternative, for example, the supply voltage and the supply current are detected and from this the expected temperature of the supply line 12A determined.

In the storage room 22 In each case, the parameter sets and characteristic curves valid for the current configuration are stored. The current configuration includes the type of utility line 12A and the type of window regulator motor used 16 , When assessing whether an overload exists, the temperature data T for the outside temperature and the number of switching states in a predetermined time interval, ie the switching frequency, are also used here. This is preferred by the control unit 10 itself determined by the timing of the switching pulses caused by it to the window regulator motor 16 is evaluated.

Is from the monitoring program 20A on overload of the supply line 12A detected, then the switch 14 opened and the window motor 16 separated from the rest of the electrical system. Subsequently, the switch 14 be closed again and the window motor 16 can resume normal operation.

This software technical line protection an effective reversible protection mechanism is realized. Due to the reversibility, unlike a fuse, no manual intervention is required after triggering of the protective mechanism. Due to the software technical realization of the line protection is also very inexpensive and there are no hardware components required. Furthermore, it is provided that the actual line cross section of the supply line 12A compared to one for the fuse value of the fuse element 4 necessary line cross section and reduced to the actual power consumption of the window motor 16 is adjusted. Preferred is as a supply line 12A a new line technology, in particular a foil line used.

In addition to the line protection is about the second monitoring program 20B a software implemented thermal protection for the window regulator motor 16 educated. Thus, the entire hierarchy level is following the controller 10 through a single program module, namely the combined program 18 protected against both overcurrent and thermal overload. The second monitoring program is used for thermal overload protection 20B also on operating data B 'of the window regulator motor 16 and evaluate these. At a thermal overload is also the switch 14 open.

2

fuse box

4

fuse element

6

management

8th

supply

10

control unit

12 12A

supply line

14

switch

16

Window motor

18

program

20A

first monitoring program

20B

second monitoring program

22

Storage

24A, B

data line

25

sensor element

26

temperature sensor

28

additional sensor element

B B '

operating data

T

temperature data

Claims (24)

Device for overload protection of a supply line ( 12A ) for an electrical load in a motor vehicle, in particular a window lift motor ( 16 ), wherein for controlling the electrical load ( 16 ) a control device ( 10 ) with a monitoring device ( 20A ) and the monitoring device ( 20A ) is designed such that on the basis of operating data (B) of the supply line ( 12A ) it is monitored for overload and disconnection of the supply line when detected for overload ( 12A ). Device according to Claim 1, in which a monitoring program ( 20A ) is provided. Apparatus according to claim 1 or 2, wherein a sensor element ( 28 ) for the direct determination of the operating data (B) of the supply line ( 12A ) is provided. Device according to one of the preceding claims, in which via the supply line ( 12A ) a burden ( 16 ) and the monitoring device ( 20A ) is designed such that on the basis of operating data (B ') of the load ( 16 ) the supply line ( 12A ) is monitored for overload. Device according to Claim 4, in which a sensor system ( 22 ) for determining the operating data (B ') of the load ( 16 ) is provided. Device according to Claim 5, in which the sensor system ( 25 ) is designed such that an engine speed of the load ( 16 ) and the supply voltage are detected and wherein furthermore a motor characteristic is stored and the monitoring program ( 20A ) is designed such that it is determined on the basis of the engine speed, the supply voltage and the motor characteristic curve, whether an overload exists. Device according to Claim 5 or 6, in which the sensor system ( 25 ) is designed such that the supply voltage and the supply current of the load ( 16 ). Device according to one of claims 4 to 7, wherein the monitoring device is designed such that the load current by means of a Ripplestromauswertung or a Hall sensor is derived. Device according to one of claims 2 to 8, in which via the supply line ( 12A ) a burden ( 16 ), for which a thermal overload protection is provided and for this purpose another monitoring program ( 20B ) implemented in such a way that on the basis of the operating data (B, B ') the load ( 16 ) is monitored for thermal overload. Device according to Claim 9, in which the monitoring program ( 20A ) and the further monitoring program ( 20B ) a combined program ( 18 ) both for overload protection of the supply line ( 12A ) as well as the thermal overload protection of the electrical load ( 16 ) form. Device according to one of the preceding claims, in which for the monitoring of the supply line ( 12A ) on overload a thermal model of the supply line ( 12A ) is based. Device according to one of the preceding claims, in which a memory ( 22 ) is provided, in which at least one characteristic is stored and the monitoring device ( 20A ) is designed such that, taking into account the current operating data (B, B ') and with the aid of the characteristic curve, a conclusion on the existence of an overload is drawn. Device according to Claim 12, in which the characteristic curve shows the relationship between an operating parameter and a temperature of the supply line ( 12A ). Device according to one of the preceding claims, in which an algorithm is provided, with the aid of which from the operating data (B, B ') the current load of the supply line ( 12A ) is calculated. Device according to one of the preceding claims, in which is a threshold for an operating parameter is stored, when it is exceeded on overload is recognized. Device according to one of the preceding claims, in which the monitoring device ( 20A ) also to check the supply line ( 12A ) is trained. Device according to one of the preceding claims, in which a temperature sensor ( 26 ) is provided for detecting the ambient temperature or a fixed temperature value for the ambient temperature is given. Device according to one of the preceding claims, in which the monitoring device ( 20A ) is designed such that, taking into account the number of switching operations of the load ( 16 ) is determined per unit of time, whether an overload exists. Device according to one of the preceding claims, in the supply line is a flat cable. Device according to one of the preceding claims, in which the supply line ( 12A ) is an FPC line with integrated electronics. Device according to one of the preceding claims, in which the supply line ( 12A ) has a plug with an integrated fuse element. Device according to one of the preceding claims, in which at the beginning of the supply line ( 12A ) a fuse element ( 14 ) for disconnecting the supply line ( 12A ) is provided. Device according to one of the preceding claims, in which a securing element ( 14 ) for disconnecting the supply line ( 12A ) outside a fuse box ( 2 ) is arranged decentrally. Device according to one of the preceding claims, in which a central fuse box ( 2 ) with a common fuse element ( 4 ) for hedging inter alia also the supply line ( 12A ) against a fuse value of the common fuse element ( 4 ) defined overload current, wherein the actual line cross-section of the supply line ( 12A ) for the expected current consumption of the load ( 16 ) and the actual line cross-section is smaller than a line cross-section required for the fuse value.