Method for operating a power distribution device for a motor vehicle, computer program product and electronic computing device

Abstract

The invention relates to a method for operating a power distribution device (12) for a motor vehicle (10) by means of an electronic computing device (14), comprising the steps of: specifying a thermal conduction model (28) for the power distribution device (12) by means of the electronic computing device (14); determining a current impulse strength of the power distribution device (12) on the basis of the thermal conduction model (28) by means of the electronic computing device (14); receiving a connection request from a non-connected component (24) of the motor vehicle (10) to the power distribution device (12) by means of the electronic computing device (14); determining a potential further impulse strength of the non-connected component (24) on the basis of the thermal conduction model (28) by means of the electronic computing device (14);Determining a total pulse strength of the power distribution device (12) with the non-connected component (24) by means of the electronic computing device (14); and determining a connection of the non-connected component (24) as a function of the total pulse strength of the power distribution device (12) and as a function of a threshold value for the total pulse strength by means of the electronic computing device (14). Furthermore, the invention relates to a computer program product and an electronic computing device (14).

Description

The present invention relates to a method for operating a power supply device for a motor vehicle by means of an electronic computing device according to the applicable patent claim 1.Electronic fuses, in particular so-called e-fuses, that is to say so-called smart FETs, replace conventional fuses in the vehicle power system. The need arises from the functional safety, which provides a very rapid, in particular a few microseconds, selective isolation of fault currents, for example a short circuit. Fuses trigger comparatively slowly, in particular in the range of several milliseconds. In vehicle power supply systems, the electronic fuses ensure protection of the line from operating resources, that is to say protection against thermal overloading. Usually, a software is used for this purpose, which decides the triggering of the electronic fuse on the basis of a current measurement and an algorithm.The so-called RMS Windowing (Route Mean Square) is known in particular from the prior art. Known RMS windowing is based on RMS current formation for a limited number of time slots of different lengths. In particular, simultaneous calculation of, for example, ten RMS values and storage of necessary current values result in resource shortage in computational performance and available memory on conventional electronic computing devices. For example, a power distributor with electronic fuses and a total of 200000 current measurement points must be continuously processed per fuse with a usual current sampling rate of 200 Hz and 1000 RMS values calculated. This is described purely by way of example. Furthermore, electronic current distribution devices according to the prior art are not necessarily designed for the simultaneous maximum superposition of all load currents, but rather for the actually occurring simultaneity of the loads on account of typical current profiles, for example driving cycles. Due to this, the simultaneous consumption of the components must be coordinated by means of the connection and electronic fuses in order not to overload the power distributor or to exceed the rating of a fuse arranged upstream.EP 2 745 303 B1 describes a fuse for connection to a protective component of an overvoltage protection device, the fuse comprising a housing, a first cap, a second cap and a fusible wire running between the first cap and the second cap within the housing, wherein the first cap is configured for thermal and electrical connection to the protective component, wherein the fusible wire is held on the first cap by means of a solder connection, wherein the fusible wire is fastened to a connection electrode opposite the first cap, wherein the connection electrode is held in a guide movably with respect to the body of the fuse and is under a mechanical bias with respect to the body of the fuse, wherein the fusible wire is configured to melt upon application of a high I 2 t, and wherein the solder connection is configured such that, the solder connection melts upon external heating by the overvoltage protection device above a specified temperature due to the thermal connection, and wherein the electrical contact between the first cap and the terminal electrode is released due to the mechanical prestress upon melting of the fusible wire as well as the solder connection.It is an object of the present invention to provide a method, a computer program product and an electronic computing device, by means of which improved operation of a power distribution apparatus within a motor vehicle can be realized.This object is achieved by a method, a computer program product and an electronic computing device according to the independent patent claims. Advantageous embodiments are specified in the dependent claims.One aspect of the invention relates to a method for operating a power distribution apparatus for a motor vehicle by means of an electronic computing device. A thermal line model for the current distribution device is predefined by means of the electronic computing device. A current pulse strength of the current distribution device is determined on the basis of the thermal model by means of the electronic computing device. A connection request of a non-connected component of the motor vehicle to the power distribution device is received by means of the electronic computing device. A potential further pulse strength of the non-connected component is determined on the basis of the thermal model by means of the electronic computing device. A total pulse strength of the current distribution device with the non-connected component is determined by means of the electronic computing device, and the connection of the non-connected component is determined as a function of the total pulse strength of the current distribution device and as a function of a threshold value for the total pulse strength by means of the electronic computing device.Thus, improved operation of the power distribution device can be realized. In particular, it is thus also possible to take account of a component which has not yet been connected and in particular to decide whether, for example, the non-connected component is connected and at the same time the threshold value for the total pulse strength is not exceeded. Corresponding fault currents or thermal temperatures above defined specifications within the current distribution device can thus be prevented. This leads to safe operation of the power distribution device.A threshold value, in particular a thermal threshold value, is determined for the already connected components. A request is then detected, for example on the basis of a communication bus of an as yet non-connected component, as to whether it is allowed to be connected. The electronic computing device then decides on the basis of the further pulse strength of the component which has not yet been connected, whether this component can be connected again. For example, this can be done in such a way that the current pulse strength is added correspondingly to the potential further pulse strength, and if the addition does not exceed the threshold value, the component that has not yet been connected can be connected reliably.For this purpose, the current distribution device can have a corresponding e-fuse, for example. The e-fuse can then, on the basis of the determined pulse strength, switch on or not switch on the further component. Furthermore, the e-fuse can then also perform a further monitoring during operation and, for example, perform a switching off of the component or also a switching off of the entire current distribution device if the predefined threshold value is exceeded accordingly. Safe operation of the power distribution device within the motor vehicle can thus be realized.According to an advantageous embodiment, a thermal capacitance and a thermal resistance and an electrical power loss are taken into account in the thermal line model. In particular, the pulse strength of the current distribution device and of the component that has not yet been connected can thus be determined in a reliable manner.It is likewise advantageous if a line resistance of the current distribution device is used to determine the electrical power loss. For example, the thermal line model is thus based on the physical line model, in particular approximated as a thermal resistance and a thermal capacitance and an electrical loss line via the line resistance. For each electronic fuse, a target triggering corridor is again predefined. This is approximated with two parameters, in particular the target pulse strength and the target continuous current. On the basis of these values, a fictitious thermal line impedance is formed. The resulting line model to be calculated and the algorithm are presented below. It is advantageous that only one integrator and a simple physically motivated model have to be calculated on each fuse. Neither many sampling points are stored nor complicated calculation operations are performed. In particular, the invention is thus based on the following mathematical formulas:The thermal conduction model is formed by:Current I 2t- Value for the Power Distribution Device:The target I 2t- value results from the sum of the component pulse (Icomp, tpulse) and the current target I 2 tvalue, wherein the component profile is approximated as a constant current pulse of the time tpulse. Alternatively, an embodiment in the form of an integral and the precise component current profile can also be used:The comparison of the possible I 2 t value of the characteristic curve I 2 t res with the target I 2 t value is determined by:With:Tc act... actual temperature of the line model (current)Ta... Ambient temperature, for example. 80° CCth... Thermal Capacitance of Line ModelRth... Thermal Resistance of the Line ModelRref... Reference Ohmic Resistance at Reference Temperature Tref of the Line ModelAlpha... Linear Temperature Coefficient of the Line ModelI 2tres... I 2 t of the line model.It has furthermore proven advantageous if a current measurement is carried out within the current distribution device in order to determine the pulse strength. In particular, the corresponding current measurement can be carried out at a specific operating point. On the basis of the current measurement, the pulse strength can be reliably determined.In a further advantageous embodiment, it is provided that, in the event of a potential exceeding of the threshold value, the non-connected component is rejected. In particular, if the total pulse strength should exceed the corresponding threshold value for the total pulse strength, the non-connected component is rejected from being connected. This prevents a corresponding thermal load within the power distribution device, whereby a reliable operation of the power distribution device can be realized.Furthermore, it has proven to be advantageous if a future pulse strength of the current distribution device is predicted and a future switchability of the non-switched-on component is determined. For example, changes in pulse strength may result due to circuit conditions of other components within the current distribution device. For example, it can be provided that a further component is switched off in the future. This in turn allows a possible engagement in the future in the event of a previous denying of the engagement. This can therefore be communicated, for example, by the electronic computing device also to the non-connected component that a connectionability is made possible in the near future.A further advantageous embodiment provides that the future switchability is determined for a predefined period of time. In particular, it is thus possible to wait until the current pulse strength is low enough to be able to satisfy the request. However, in particular the time window, in particular a so-called time-out, is necessary for this purpose in order not to unexpectedly execute a request for an impermissible long pause.It has furthermore proven advantageous if at least one current value for the activation and one duration of the activation are transmitted by the non-activated component by means of the activation request. Thus, the non-connected component can also package corresponding parameters into the connection request, so that a reliable determination of the overall pulse strength is made possible. On the basis of the current values and the duration, it can thus be decided whether the non-connected component can be connected.The presented method is in particular a computer-implemented method. Therefore, a further aspect of the invention relates to a computer program product having program code means which cause an electronic computing device, when the program code means are executed by the electronic computing device, to carry out a method according to the preceding aspect. Furthermore, the invention also relates to a computer-readable storage medium having at least the computer program product according to the preceding aspect.Yet another aspect of the invention relates to an electronic computing device for a power distribution device for a motor vehicle, wherein the electronic computing device is designed to carry out a method according to the preceding aspect. In particular, the method is carried out by means of the electronic computing device.Furthermore, the invention also relates to a current distribution device having at least one electronic computing device and at least one non-connected component. Furthermore, the current distribution device can also have, in particular, a so-called e-fuse.Yet another aspect of the invention also relates to a motor vehicle having at least one current distribution device according to the preceding aspect.Advantageous embodiments of the method are to be regarded as advantageous embodiments of the computer program product, the computer-readable storage medium, the electronic computing device, the power distribution device and the motor vehicle. The motor vehicle, the power distribution device and the electronic computing device have features for this purpose in order to be able to carry out corresponding method steps.A computing unit / electronic computing device can be understood in particular as a data processing device which contains a processing circuit. The computing unit can therefore process data in particular for carrying out computing operations. This also includes operations to perform indexed accesses to a data structure, for example a look-up table (LUT).The computing unit can in particular contain one or more computers, one or more microcontrollers and / or one or more integrated circuits, for example one or more application-specific integrated circuits, ASICs (application-specific integrated circuit), one or more field programmable gate arrays, FPGAs, and / or one or more single-chip systems, SoCs (system on a chip). The computing unit may also contain one or more processors, for example one or more microprocessors, one or more central processing units, CPUs (central processing units), one or more graphics processing units, GPUs (graphics processing units) and / or one or more signal processors, in particular one or more digital signal processors, DSPs. The computing unit may also include a physical or virtual group of computers or other of the aforementioned units.In various exemplary embodiments, the computing unit contains one or more hardware and / or software interfaces and / or one or more memory units.A memory unit can be used as volatile data memory, for example as dynamic random access memory, DRAM (dynamic random access memory) or static random access memory, SRAM (static random access memory), or as nonvolatile data memory, for example as read-only memory, ROM (read-only memory), as programmable read-only memory, PROM (programmable read-only memory), as erasable programmable read-only memory, EPROM (erasable programmable read-only memory), as electrically erasable programmable read-only memory, EEPROM (electrically erasable programmable read-only memory), as flash memory or flash EEPROM, as ferroelectric random access memory, FRAM (ferroelectric random access memory), as magnetoresistive random access memory, MRAM (magnetoresistive random access memory) or as phase-change random access memory, PCRAM (phase-change random access memory).Further features of the invention are evident from the claims, the figures and the description of the figures. The features and combinations of features mentioned above in the description and the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures can be used not only in the respectively specified combination but also in other combinations or alone.The invention will now be explained in more detail on the basis of a preferred exemplary embodiment and with reference to the drawings. The following are shown: FIG. 1 shows a schematic side view of an embodiment of a motor vehicle in an embodiment of a circuit apparatus having an embodiment of electronic computing device; and FIG. 2 is a schematic block diagram according to an embodiment of a power distribution device.In the figures, identical or functionally identical elements are provided with identical reference symbols.FIG. 1 shows a schematic side view of an embodiment of a motor vehicle 10. Furthermore, the current distribution device 12 has at least one electronic computing device 14.FIG. 2 shows a schematic block diagram according to an embodiment of the power distribution apparatus 12. In the following exemplary embodiment, the current distribution device 12 also has an e-fuse 16 and a current measuring device 18. Further shown are a first component 20, a second component 22, and a third component 24. In the present exemplary embodiment, the first component 20 and the second component 22 are in particular connected, while the third component 24 is shown as a non-connected component 24.The e-fuse 16 and further e-fuses 26 can be controlled accordingly, in particular via the electronic computing device 14. The e-fuses 26 can be individually switched with respect to one another.FIG. 2 shows in particular a method for operating the power distribution device 12. An actual pulse strength of the current distribution device 12 is determined on the basis of the thermal line model 28 by means of the electronic computing device 14. A connection request for the non-connected component 24 of the motor vehicle 10 to the power distribution device 12 is received by means of the electronic computing device 14. A total pulse strength of the current distribution device 12 with the non-connected component 24 is determined by means of the electronic computing device 14.In this case, provision can be made in particular for a thermal capacitance, a thermal resistance and an electrical loss line to be taken into account in the thermal line model 28. In this case, it can furthermore be provided that a line resistance of the current distribution device 12 is used for determining the electrical power loss. Furthermore, for determining the pulse stability, a current measurement can be carried out, in particular by means of the current measuring device 18, in the current distribution device 12. Furthermore, it can be provided that, if the threshold value is potentially exceeded, the non-connected component 24 is rejected from being connected.Furthermore, it can be provided in particular that a future pulse strength of the current distribution device 12 is predicted and a future switchability of the non-switched-on component 24 is determined. In this case, the future switchability can be determined for a predefined period of time.Furthermore, it can be provided that at least one current value for the activation and a duration of the activation are transmitted by the non-activated component 24 by means of the activation request.In particular, FIG. 2 thus shows that the thermal line model 28 can be provided by means of the physical line model, in particular approximated as a thermal resistance and a thermal capacitance and an electronic power loss such as the line resistance. For each electronic fuse, a target triggering corridor is specified. This is approximated with the two parameters "target pulse strength" and "target continuous current". On the basis of these values, a fictitious thermal line impedance is formed. The resulting line model to be calculated and the algorithm are mathematically presented below:The thermal conduction model is formed by:Current I 2t- Value for the Power Distribution Device:The target I 2t- value results from the sum of the component pulse (Icomp, tpulse) and the current target I 2t- value, wherein the component profile is approximated as a constant current pulse of the time tpulse. Alternatively, an embodiment in the form of an integral and the precise component current profile can also be used:The comparison of the possible I 2 t value of the characteristic curve I 2 t res with the target I 2 t value is determined by:With:Tc act... actual temperature of the line model (current)Ta... Ambient temperature, for example. 80° CCth... Thermal Capacitance of Line ModelRth... Thermal Resistance of the Line ModelRref... Reference Ohmic Resistance at Reference Temperature Tref of the Line ModelAlpha... Linear Temperature Coefficient of the Line ModelI 2 t res... I 2 t of the line model.The advantage is that only one integrator and one simple physically motivated model have to be calculated for each fuse. Neither many sampling points are stored nor complicated calculation operations need to be performed.The current pulse strength within the connected components of the current distribution device 12 is determined. A threshold value, in particular a thermal threshold value, is determined for the already connected components. A request is then detected, for example on the basis of a communication bus of a component 24 which has not yet been connected, whether it is allowed to be connected. The electronic computing device 14 then decides on the basis of the further pulse strength of the component 24, which has not yet been connected, whether this component can be connected again. For example, this can be done in such a way that the current pulse strength is added correspondingly to the potential further pulse strength, and if these do not exceed the threshold value, the component 24 that has not yet been connected can be connected reliably.Moreover, this thermal line model 28 is now used to calculate the connectivity of the non-connected component 24. For this purpose, initially the current pulse strength of the current distributor or of a point is currently calculated by means of the pulse strength I 2t. For this purpose, the temperature model mentioned and the current measurement at this evaluation point can be used, for example when feeding into the current distributor. If components connected to the power distributor, in particular the non-connected component 24, are now to be connected, said component sends a request to the electronic power distributor on the communication bus. This calculates the request, in particular as current value, time-, for example as pulse current, from the current pulse strength, and approximates the target pulse strength I 2t. This makes it possible to predict which pulse resistance the current distributor would have at the evaluation point after the non-connected component 24 has been connected and executed its actuator system and thus in particular consumed a requested pulse current. If this target pulse strength is too high, the connection is rejected. Alternatively or additionally, it would be possible to wait until the current pulse strength is low enough to be able to satisfy the request. This again requires a timeout in order not to unexpectedly execute a request for an unacceptably long pause.List of reference characters10 Motor vehicle 12 Current distribution device 14 Electronic computing device 16 e-fuse 18 Current measuring device 20 First component 22 Second component 24 Non-connected component 26 Further e-fuse 28 Thermal modelReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedEP 2 745 303 B1

[0004]

Claims

Method for operating a power distribution device (12) for a motor vehicle (10) by means of an electronic computing device (14), having the steps: - presetting a thermal line model (28) for the power distribution device (12) by means of the electronic computing device (14); - determining a current pulse strength of the power distribution device (12) on the basis of the thermal line model (28) by means of the electronic computing device (14); - receiving a connection request of a non-connected component (24) of the motor vehicle (10) to the power distribution device (12) by means of the electronic computing device (14); - determining a potential further pulse strength of the non-connected component (24) on the basis of the thermal line model (28) by means of the electronic computing device (14); determining a total pulse strength of the current distribution device (12) with the non-connected component (24) by means of the electronic computing device (14); and determining a connection of the non-connected component (24) as a function of the total pulse strength of the current distribution device (12) and as a function of a threshold value for the total pulse strength by means of the electronic computing device (14).Method according to Claim 1, characterized in that a thermal capacitance and a thermal resistance and an electrical power loss are taken into account in the thermal line model (28).Method according to Claim 2, characterized in that a line resistance of the current distribution device (12) is used to determine the electrical power loss.Method according to one of the preceding claims, characterized in that a current measurement is carried out in the current distribution device (12) in order to determine the pulse strength.Method according to one of the preceding claims, characterized in that, if the threshold value is potentially exceeded, the non-connected component (24) is rejected from being connected.Method according to one of the preceding claims, characterized in that a future pulse strength of the current distribution device (12) is predicted and a future switchability of the non-switched-on component (24) is determined.Method according to Claim 6, characterized in that the future switchability is determined for a predefined period of time.Method according to one of the preceding claims, characterized in that the non-activated component (24) transmits at least one current value for activation and one duration of activation by means of the activation request.Computer program product having program code means which cause an electronic computing device (14), when the program code means are executed by the electronic computing device (14), to carry out a method according to one of Claims 1 to 8.Electronic computing device (14) for a power distribution apparatus (12) for a motor vehicle (10), wherein the electronic computing device (14) is designed to carry out a method according to one of Claims 1 to 8.

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