Fuse arrangement for a vehicle's electrical system

Abstract

Fuse arrangement (100) for an on-board electrical system of a vehicle, wherein the fuse arrangement (100) comprises: at least one supply path (200) in which an electronic fuse (220) is arranged, wherein an input of the at least one supply path (200) can be connected to at least one energy source (240); at least one sub-path (400) in which a fuse (420) is arranged, wherein an input of the at least one sub-path (400) is connected to an output of the at least one supply path (200) and an output of the at least one sub-path (400) is connectable to a consumer (440); and at least one energy storage device arranged between the at least one supply path (200) and the at least one sub-path (400) such that a connection of the at least one energy storage device is connected to the output of the at least one supply path (200) and the input of the at least one sub-path (400), wherein the at least one supply path (200) has a plurality of supply paths (200) or is designed as a plurality of supply paths (200) and the at least one energy storage device has a plurality of energy storage devices or is designed as a plurality of energy storage devices and each terminal of the plurality of energy storage devices is connected to an associated output of one of the plurality of supply paths (200).

Description

[0001] The present invention relates to a safety arrangement for a vehicle's electrical system, an electrical system with such a safety arrangement, and a vehicle with such a safety arrangement and / or with such an electrical system.

[0002] To protect conventional power supply networks, each line to a consumer is often individually protected by an overcurrent protection device (e.g., a fuse). Upstream supply lines (so-called feeder lines, distribution lines, or feeder lines) are also protected by correspondingly larger fuses. If a fault occurs in a supply line (e.g., a ground fault), the corresponding fuse trips, and the associated consumer(s) are disconnected from the power supply network. This ensures reliable protection of power supply networks.

[0003] In vehicle electrical systems, electronic fuses at a higher / superordinate level are often combined with non-electronic fuses, such as cartridge fuses, at a lower / subordinate level. This can lead to problems with the selectivity of the fuse paths, as cartridge fuses generally react more slowly to overcurrent than electronic fuses. Consequently, a short circuit at a lower fuse level, protected by cartridge fuses, does not necessarily mean that the cartridge fuse will blow. Instead, an electronic fuse at a higher level may blow. This, in turn, means that the fault at the lower fuse level cannot be isolated, and the entire lower fuse level, which is connected to the tripped higher fuse path, fails.

[0004] In summary, it can be said that a combination of non-electronic fuses, such as fuse links, and electronic fuses at different protection levels can cause problems in the power supply of vehicles.

[0005] DE 10 2013 003 586 A1 relates to an electrical power supply system for a motor vehicle. The electrical power supply system comprises an electrical electrical network, a first electrical conductor path, a second electrical conductor path, and at least one third electrical conductor path. The first electrical conductor path connects an electrical power supply unit to the electrical electrical network by means of a first electrical fuse. The second electrical conductor path connects an electrical generator unit to the electrical electrical network by means of a semiconductor switch. The at least one third conductor path connects each electrical consumer to the electrical electrical network by means of a second electrical fuse. Each second electrical fuse has a shorter response time than the first electrical fuse.The first and second electrical safety elements can be designed as fuse links.

[0006] DE 10 2013 003 586 A1 therefore describes an electrical power supply system in which a first and at least a third conductor path are equipped with fuses and a second conductor path is equipped with a semiconductor switch. DE 10 2013 003 586 A1 proposes that the respective second electrical fuse element has a shorter response time than the first electrical fuse element. In this way, it is ensured that in the event of an electrical short circuit, for example in the electrical load or...In the third electrical circuit, in which this electrical consumer is located, only the consumer is electrically disconnected from the vehicle's electrical system by the activation of the second electrical fuse associated with this electrical consumer, whereas the remaining electrical consumers remain electrically connected to the vehicle's electrical system and are consequently not affected by the fault / malfunction in the third electrical circuit. However, DE 10 2013 003 586 A1 does not disclose how the tripping behavior of fuses on the one hand and semiconductor switches on the other relates to each other and whether it can even be influenced.

[0007] Therefore, there is a need for a reliable safety arrangement with a fuse, for example a cartridge fuse, and an electronic fuse in different paths, preferably in serially connected paths, as well as for an associated vehicle network and an associated vehicle.

[0008] According to a first aspect of the invention, a fuse arrangement for a vehicle's electrical system is proposed. The fuse arrangement has at least one supply path. An electronic fuse is arranged in each of the at least one supply path. An input of the at least one supply path can be connected to at least one energy source of the vehicle. The fuse arrangement has at least one sub-path. A fuse is arranged in each of the at least one sub-path. An input of the at least one sub-path is connected to an output of the at least one supply path. An output of the at least one sub-path can be connected to a load. The fuse arrangement has at least one energy storage device. The at least one energy storage device is arranged between the at least one supply path and the at least one sub-path.One connection of the at least one energy storage device is connected to the output of the at least one supply path and the input of the at least one sub-path.

[0009] If a short circuit occurs in one of the at least one loads, electrical energy is drawn not only from the at least one energy source that normally provides the power supply, but also from the at least one energy storage device connected to the corresponding sub-path. As a result, the short-circuit current, which would otherwise trip the fuse (e.g., the cartridge fuse) of the corresponding sub-path, does not flow entirely through the electronic fuse of the supply path connected to that sub-path. This ensures that the short-circuit current does not reach the tripping current / maximum current of the electronic fuse of the corresponding supply path and therefore does not trip.If the electronic fuse of the corresponding supply path does not trip, consequently not all of the at least one sub-path connected to the corresponding supply path are disconnected, but ideally only the consumer in which the short circuit occurred is disconnected via the associated fuse, e.g. fuse.

[0010] The at least one energy storage device can be configured to store energy, at least temporarily. The at least one energy storage device can be rechargeable, i.e., it can be charged with energy. The at least one energy storage device can be discharged, at least temporarily, at least partially, i.e., it can release stored energy, at least temporarily. The at least one energy storage device can include at least one capacitor or be configured as at least one capacitor. Additionally or alternatively, the at least one energy storage device can include at least one battery or at least one accumulator, or be configured as at least one battery or at least one accumulator.Additionally or alternatively, the at least one energy storage device can have at least one converter, for example a DC-DC converter, or be designed as at least one converter, for example a DC-DC converter.

[0011] As described, a fuse is arranged in each of the at least one sub-paths. Each fuse can be a cartridge fuse or designed as a cartridge fuse. Each fuse can include a (non-electronic) overcurrent protection device or be designed as a (non-electronic) overcurrent protection device. The fuse can be a non-electronic fuse or be designed as a non-electronic fuse. A non-electronic fuse can be understood to be any type of fuse that differs from an electronic fuse. That is, a non-electronic fuse can be understood to be any type of fuse that is not electronic. The electronic fuse can include an electronic switch or be designed as one or more electronic switches.

[0012] Fuses protect the components in electrical circuits. In the event of an overload or short circuit, the fuse trips and opens the circuit. This limits the damage and avoids repair costs. Ideally, the tripping characteristic of a fuse is designed so that the current is interrupted before other components, such as wires, semiconductors, or passive components in the circuit, are damaged. Consequently, a properly sized fuse is the weakest link in the circuit. The thermal characteristics of the object being protected, such as the electrical wiring, the cable harness, or semiconductor switches in a connected control unit, are crucial factors.

[0013] An electronic fuse is an electronic protective device that automatically disconnects an electrical circuit in the event of a short circuit or overload, representing a form of electronic overcurrent protection. Compared to conventional circuit breakers, electronic overcurrent protection offers the advantage of triggering very quickly, even after a brief exceedance of a certain current value, and / or even with a small overcurrent. This ensures reliable disconnection even with long cables and small conductor cross-sections.

[0014] Electronic fuses, instead of using fusible links or electromagnetically triggered mechanical contacts, contain one or more semiconductor switches, including their control logic with protective and diagnostic functions. Electronic fuses can be tripped and reset any number of times. Unlike traditional fuses, electronic fuses require their own power. The tripping behavior of an electronic fuse can be defined and adjusted. For example, it is possible to first limit the current and then switch it off, or to switch it off immediately and wait for it to reset. Since an electronic fuse already contains a switch, it can also be used in this function. This eliminates the need for additional switches and enables further functions such as soft start by controlling the switch with pulse-width modulation (PWM).

[0015] In the event of an overload, the electronic fuse can react quickly and flexibly. In the event of a short circuit, it disconnects more quickly, resulting in a shorter-lasting voltage drop in the rest of the vehicle's electrical system. This is important for the electronic circuits installed there, which, after a prolonged voltage drop followed by a power-up, must undergo a reset and boot process before they can function again. For critical driver assistance systems that would fail during the boot process while driving, this would pose a risk to their reliable power supply. The electronic fuse can be designed to limit the current flowing through it to a specific maximum value before disconnecting. Even in the event of a short circuit, this prevents the vehicle's electrical system voltage from dropping so low that other control units go into reset mode.

[0016] The electronic fuse can have a predetermined tripping current value. The tripping current value of an electronic fuse can be understood as the value of an electric current above which the fuse trips. Even a brief exceedance of the tripping current value by a current flowing through the electronic fuse can cause it to trip.

[0017] Fuses, such as cartridge fuses or other non-electronic overcurrent protection devices, serve to protect loads and wiring from overcurrents, such as short-circuit currents. Protection of wiring and equipment from overload and short circuits is achieved by the fuse, for example, the cartridge fuse, interrupting the current flow at a specific current level. A cartridge fuse can therefore be considered a special type of overcurrent protection device or a special type of non-electronic fuse. Overcurrent protection in a cartridge fuse is achieved by the melting of a designated fusible element, such as a fuse wire, interrupting the circuit when the current flowing through the cartridge fuse exceeds a certain value for a sufficient period of time.The fusible link is designed to withstand the fuse's rated current for a specific period. As the current increases, the relatively thin fusible link heats up until it begins to melt. When the rated current is exceeded by a certain amount and for a specific duration, the link melts, breaking the circuit. In other words, if the fuse carries an excessively high current (i.e., at least a current above the rated current), it will begin to melt and interrupt the circuit after a certain time. Put another way, the fuse is designed to break the current flow through it by melting when the current exceeds a predetermined rated current for a specified period. Unlike electronic fuses, once a fuse has blown, it cannot be reused and must be replaced.Conventional fuses are characterized by their rated current and tripping characteristics. Generally, however, their tripping behavior is slower than that of electronic fuses.

[0018] In summary, the at least one electronic fuse can have a predetermined tripping current value. Even a brief exceedance of this tripping current value can trigger the at least one electronic fuse. The at least one fuse, e.g., the at least one cartridge fuse, in the fuse arrangement can have a predetermined rated current value. If the rated current value is exceeded for a predetermined time, the at least one fuse, e.g., the at least one cartridge fuse, can trigger. The tripping current value of the at least one electronic fuse can be higher than the rated current value of the at least one fuse, e.g., the at least one cartridge fuse.Nevertheless, an electronic fuse can generally trip earlier than a non-electronic fuse, since with an electronic fuse even a brief exceedance of the tripping current value can be sufficient to trigger it, whereas with fuse links the rated current value must be exceeded for a predetermined time.

[0019] The load can be connected to a reference potential. The reference potential can be at a lower potential than the at least one supply path or than the supply side (energy source side) in general. The reference potential can be ground, i.e., the reference potential can be at ground. One terminal of the at least one energy storage device, for example, the at least one capacitor, is connected to the output of the at least one supply path and the input of the at least one sub-path. Another terminal of the at least one energy storage device, for example, the at least one capacitor, can be connected to a reference potential. The reference potential can be at a lower potential than the at least one supply path or than the supply side in general. The reference potential can be ground, i.e.,The reference potential can be ground. In other words, the at least one energy storage device, for example the at least one capacitor, can be arranged between the at least one supply path and the at least one sub-path such that one terminal of the at least one energy storage device, for example the at least one capacitor, is connected to the output of the at least one supply path and the input of the at least one sub-path, and another terminal of the at least one energy storage device, for example the at least one capacitor, is connected to a reference potential, for example ground.

[0020] A path, such as a supply path and / or sub-path, can be understood as any suitable electrical connection between an input terminal and an output terminal. One or more components, such as electrical or electronic components, can be arranged in such a path. The at least one supply path can also be referred to as the supply path. The at least one sub-path can also be referred to as the load path. The path in which the at least one energy storage device, for example, the at least one capacitor, is connected to a reference potential, such as ground, can also be referred to as the energy storage path (or alternatively, in the case of at least one capacitor being used as the energy storage device, as the capacitor path).As an alternative to connecting the at least one energy storage device, for example the at least one capacitor, one can also speak of one side of the at least one energy storage device, for example the at least one capacitor, so that one side of the at least one energy storage device, for example the at least one capacitor, can be connected to the output of the at least one supply path and the input of the at least one sub-path and another side of the at least one energy storage device, for example the at least one capacitor, can be connected to a reference potential, e.g. to ground.

[0021] The at least one energy source can, for example, comprise an electrical or electrochemical energy storage device or be designed as such. The at least one energy source can, for example, comprise a non-rechargeable or rechargeable energy source or be designed as such. For example, the at least one energy source can comprise a non-rechargeable or rechargeable battery, such as an accumulator, or be designed as such. The at least one energy source can, for example, comprise a converter or a generator, or be designed as such.

[0022] The at least one electrical consumer can be any component that can generally be used in a vehicle's electrical system, or be configured as such. Accordingly, the at least one electrical consumer can be an electrical component or be configured as one. The at least one electrical consumer can be a non-safety-relevant component and / or a safety-relevant component, or be configured as a non-safety-relevant component and / or as a safety-relevant component. Examples of safety-relevant components in an electrical system include electronic power steering or brake booster systems.

[0023] The at least one supply path has a plurality of supply paths or is configured as a plurality of supply paths. The at least one energy storage device, for example, the at least one capacitor, has a plurality of energy storage devices, for example, a plurality of capacitors, or is configured as a plurality of energy storage devices, for example, a plurality of capacitors. Each terminal of the plurality of energy storage devices, for example, each of the plurality of capacitors, is connected to a corresponding output of one of the plurality of supply paths. The number of the plurality of energy storage devices, for example, the plurality of capacitors, can be matched to the number of the plurality of supply paths. According to one embodiment, the number of the plurality of energy storage devices, for example, the plurality of capacitors, can correspond to the number of the plurality of supply paths.According to this embodiment, exactly one energy storage device, for example, exactly one capacitor, can be provided for each supply path of the plurality of supply paths. According to this embodiment, each of the plurality of energy storage devices, for example, each of the plurality of capacitors, can be connected to a corresponding output of one of the plurality of supply paths. For example, each terminal of each of the plurality of energy storage devices, for example, each of the plurality of capacitors, can be connected to a corresponding output of one of the plurality of supply paths.

[0024] The at least one subpath can have a plurality of subpaths or be configured as a plurality of subpaths. Several of the plurality of subpaths can be connected to the at least one supply path. For example, each of the plurality of supply paths can be connected to one or more of the plurality of subpaths. The number of the plurality of subpaths can be greater than the number of the plurality of supply paths. The number of the plurality of subpaths can be greater than the number of the plurality of energy storage devices, for example, the plurality of capacitors. According to one embodiment, two or more of the plurality of supply paths can each be connected to several of the plurality of subpaths. In other words, each of the plurality of supply paths can be connected to several of the plurality of subpaths.Between each feeder path and the sub-paths connected to that feeder path, an energy storage device, for example a capacitor, can be arranged as described. For example, exactly one of the multiple feeder paths can be connected to each of the multiple energy storage devices, for example exactly one of the multiple capacitors, and several of the multiple sub-paths.

[0025] The safety arrangement may further include a control unit. The control unit may be configured to limit the current flow through the at least one supply path for charging the at least one energy storage device, for example, the at least one capacitor, to a predetermined limit during a switch-on process. In this way, the current flow through the electronic fuse of the at least one supply path is limited to a predetermined limit, which is, for example, below the tripping current of the at least one electronic fuse. As a result, the at least one electronic fuse does not trip unintentionally during the switch-on process and / or during the charging of the at least one energy storage device, for example, the at least one capacitor.Additionally or alternatively, the control unit can be configured to gradually increase the current flow through the at least one supply path for charging the at least one energy storage device, for example, the at least one capacitor. In this way, the current flow through the electronic fuse of the at least one supply path is increased only slowly. As a result, the at least one electronic fuse does not trip, or trips less frequently or less easily, during the switch-on process and / or during the charging of the at least one energy storage device, for example, the at least one capacitor.Additionally or alternatively, the control unit can be configured to activate the electronic fuse of the at least one supply line path after a predetermined time interval during a power-on process. This fuse measures the current flow through the at least one supply line path for charging the at least one energy storage device, for example, the at least one capacitor. Therefore, the current flow through the at least one supply line path is not monitored by the at least one electronic fuse before the predetermined time interval has elapsed. Consequently, the at least one electronic fuse does not trip unintentionally during the power-on process and / or while charging the at least one energy storage device, for example, the at least one capacitor, before the predetermined time interval has elapsed.

[0026] The fuse arrangement can further comprise at least one resistor. This resistor can be connected in series with the at least one energy storage device, for example, the at least one capacitor. The resistor increases the overall resistance of the at least one energy storage path, for example, the at least one capacitor path, in which the at least one energy storage device (e.g., the at least one capacitor) and the resistor are arranged and connected, for example, to a reference potential, such as ground.Due to the increased overall resistance, during a switch-on and / or charging process of the at least one energy storage device, for example, the at least one capacitor, a lower current will flow through the at least one energy storage path, for example, the at least one capacitor path, and the associated supply path. This reduces the risk of the electronic fuse of the at least one supply path tripping during a switch-on process. However, this also reduces the current that flows through the at least one energy storage path, for example, the at least one capacitor path, in the event of a fault in the at least one sub-path, thus increasing the current flow through the at least one supply path.If a large number of energy storage devices, for example a large number of capacitors, are provided, a corresponding large number of resistors can be provided, e.g. exactly one energy storage device and exactly one resistor per energy storage path, for example exactly one capacitor and exactly one resistor per capacitor path.

[0027] The fuse arrangement can include at least one diode arrangement. Each diode arrangement can be connected in series with the at least one energy storage device, for example, the at least one capacitor. Each diode arrangement can include a first diode, a first resistor, a second diode, and a second resistor. The diode arrangement can be located, for example, between the energy storage device, such as the capacitor, and the output of the associated supply path. The first diode can be configured and arranged such that its forward direction points towards the energy storage device, such as the capacitor. The second diode can be configured and arranged such that its forward direction points towards the output of the at least one supply path and the input of the at least one sub-path.The resistance value of the first resistor can be higher than the resistance value of the second resistor. Due to the increase in the total resistance (especially in the forward direction of the first diode), a smaller current will flow through the energy storage path with the energy storage device, for example, through the capacitor path with the capacitor, and the associated supply path during a switch-on process. This reduces the risk of the electronic fuse of the at least one supply path tripping during a switch-on process. Furthermore, the total resistance increases less in the other direction (in the forward direction of the second diode). As a result, the current flowing through the associated energy storage path with the at least one energy storage device, for example, the associated capacitor path with the at least one capacitor, in the event of a fault in the at least one sub-path is reduced to a lesser extent (e.g.,(Compared to simply connecting the energy storage device, for example the capacitor, with a larger resistance), the current flow through the at least one supply path increases only slightly. If a large number of energy storage devices, for example a large number of capacitors, are provided, a corresponding number of diode arrangements can be provided, e.g., exactly one energy storage device and exactly one diode arrangement per energy storage path, for example, exactly one capacitor and exactly one diode arrangement per capacitor path.

[0028] According to a second aspect, a vehicle electrical system is proposed. The electrical system has a fuse arrangement as described herein. The electrical system also has at least one power source. This power source is connected to an input of the fuse arrangement. Furthermore, the electrical system has at least one load. This load is connected to an output of the fuse arrangement.

[0029] For example, the vehicle electrical system has a multitude of energy sources. Each of these energy sources can be connected to one or more of the numerous supply paths. Similarly, the vehicle electrical system has a multitude of consumers. Each of these consumers can be connected to one of the numerous sub-paths.

[0030] A third aspect is required for a vehicle. This vehicle has a safety arrangement as described herein and / or an electrical system as described herein. The vehicle may be at least partially electrically powered.

[0031] The term "vehicle" here can refer to various motor vehicles and / or land vehicles. Examples of motor vehicles include, but are not limited to, passenger cars, trucks, tractors, self-propelled work machines, and commercial vehicles. For instance, this includes construction site or industrial vehicles (excavators, forklifts, trucks, etc.).

[0032] Even though some of the aspects described above relating to the fuse arrangement were described according to the first aspect, these aspects may also be implemented in a corresponding manner in the vehicle electrical system according to the second aspect and / or in the vehicle according to the third aspect. Furthermore, details described relating to the vehicle electrical system according to the second aspect may also be implemented in a corresponding manner in the fuse arrangement according to the first aspect and / or in the vehicle according to the third aspect.

[0033] The present revelation will be further explained using figures. These figures schematically depict: Fig. 1a an on-board electrical system with a conventional fuse arrangement; Fig. 1b an on-board electrical system with a fuse arrangement according to an example; Fig. 2 a vehicle electrical system with a fuse arrangement according to an exemplary embodiment; Fig. 3 a vehicle electrical system with a fuse arrangement according to a first variant of the embodiment from Fig. 2; Fig. 4 a vehicle electrical system with a fuse arrangement according to a second variant of the embodiment from Fig. 2; and Fig. 5 a diode arrangement, which in the second variant of the embodiment according to Fig. 4 can be used.

[0034] Specific details are set forth below, without limitation, to provide a complete understanding of the present disclosure. However, it is clear to a person skilled in the art that the present disclosure can be used in other embodiments which may differ from the details set forth below. For example, specific configurations and embodiments are described below, which are not to be considered limiting.

[0035] Fig. Figure 1a shows a vehicle electrical system with a conventional fuse arrangement 1. The fuse arrangement 1 has at least one supply path 20 and at least one sub-path 40. A fuse 42 is arranged in each of the at least one supply path 20. An input of the at least one supply path 20 can be connected to at least one power source 24 of a vehicle. A fuse 42 is arranged in each of the at least one sub-path 40. An input of the at least one sub-path 40 is connected to an output of the at least one supply path 20. An output of the at least one sub-path 40 can be connected to a load 44 connected to ground.

[0036] In such a classic on-board network as the one from Fig. In section 1a, which contains only fuses 42, there are various protection levels corresponding to the branches of the power supply 24 of all consumers 44. Since a short circuit can occur at any point in the vehicle electrical system, it is not sufficient to install only one fuse per consumer 44; additional protective elements are necessary on the common supply lines 20. If a short circuit is always isolated in such a way that only the faulty subnetwork (for example, the subpath 40 in which the fault occurs) is switched off, this is referred to as guaranteed selectivity. A violation of this selectivity would occur, for example, if a short circuit in a single consumer 44 were to unnecessarily switch off an entire group of consumers because the fuse 42 of the consumer group of the single consumer 44 in which the short circuit occurred trips before the fuse 42 of the faulty consumer 44.If only fuses 42 are used, this is very easy to achieve by installing fuses 42 with progressively smaller fuse ratings (with progressively smaller rated current values) on a single energy path, starting at the energy source 24 and ending at an electrical consumer 44.

[0037] With the increasing integration of safety-relevant components into the vehicle's electrical system, such as electronic power steering or brake boosters, a reliable power supply for these components is becoming ever more important. Particularly in the event of a short circuit, the voltage can drop so drastically and for such a long time that the functionality of these safety-relevant functions can no longer be reliably guaranteed by conventional fuses. Electronic fuses offer a possible alternative; these can be controlled externally, for example, by disconnecting contacts within the vehicle's electrical system. Electronic fuses can be controlled externally (from outside the fuse itself) via a control logic circuit.This required increased flexibility, however, comes at the cost of higher development and material expenses. Therefore, from both a complexity and / or economic perspective, a complete replacement of conventional fuses with electronic switching components is not desirable. Instead, a compromise optimized for effort and / or cost is preferred. This compromise should guarantee the necessary safety requirements with the fewest possible electronic components. Replacing a fuse is particularly advisable when high currents are expected, as the high fuse rating reacts very slowly to an overcurrent, thus increasing the risk of prolonged undervoltage elsewhere in the electrical system. Particularly high fuse ratings are typically installed near power sources, as this is where the combined currents of entire groups of consumers occur.Therefore, consideration can be given to replacing fuses near energy sources with electronic fuses.

[0038] Due to their different operating principles, fuse links and electronic fuses cannot be combined arbitrarily. A cost-optimized safety concept could be achieved using the following generic current path of an on-board electrical system (see example). Fig. 1b) The circuit is structured as follows: “Energy source – electronic fuse – fuse – consumer”. The type and number of energy sources used and the number of sub-paths into which the vehicle electrical system is divided are irrelevant.

[0039] Fig. Figure 1b shows an on-board electrical system with a fuse arrangement 10 according to an example. The fuse arrangement 10 has at least one supply path 20 and at least one sub-path 40. An electronic fuse 22 is arranged in each of the at least one supply path 20. An input of the at least one supply path 20 can be connected to at least one power source 24 of a vehicle. A fuse 42 is arranged in each of the at least one sub-path 40. An input of the at least one sub-path 40 is connected to an output of the at least one supply path 20. An output of the at least one sub-path 40 can be connected to a load 44 connected to ground.

[0040] In Fig. Figure 1b shows three supply paths 20 as an example of at least one supply path 20. Accordingly, three power sources 24 (e.g., one power source 24 per supply path 20) and three electronic fuses 22 (one electronic fuse 22 per supply path 20) are provided. The middle (second) of the three supply paths 20 has three sub-paths 40 as an example of at least one sub-path 40. The upper (first) and lower (third) supply paths 20 each also have one or more sub-paths 40, for example, three sub-paths 40. Each of the three sub-paths 40 of the middle (second) supply path 20 has a fuse 42. In addition, the three sub-paths 40 of the middle (second) supply path 20 are each connected to a consumer 44 (even though this is only shown for the middle (second) of the three sub-paths 40).The consumers 44 are each connected to ground. Likewise, a fuse 42 is provided in each of the sub-paths 40 of the upper (first) and lower (third) supply path 20 (not shown). Likewise, each of the sub-paths 40 of the upper (first) and lower (third) supply path 20 (not shown) is connected to a consumer 44, which in turn is connected to ground.

[0041] If only electronic fuses were installed, as in relation to Fig. As outlined in Figure 1a, selectivity is achieved by decreasing nominal current values ​​from energy sources 24 towards consumers 44. However, due to the different nature of the two protection concepts (electronic fuses 22 in the supply paths 20 and fuse links 42 in the sub-paths 40), ensuring selectivity becomes a non-trivial problem when both types of protection are installed in series on one path (from energy source 24 to consumer 44). This is because electronic fuses 22 typically limit the instantaneous value of the electric current, while fuse links 42 tend to limit the current integral; therefore, the tripping time above a defined limiting current is not constant but depends on the current.Referring to a generic consumer path from energy source 24, via an electronic fuse 22 and a fuse 42 to a consumer 44, this can specifically mean that a short circuit in a non-safety-relevant consumer 44 can lead to the failure of safety-relevant functions. This occurs, for example, if a short circuit in a non-safety-relevant consumer 44 causes a corresponding electronic fuse 22 (at a higher level) to trip upstream of the corresponding fuse 42, and a safety-relevant consumer 44 is connected to the supply path 20 of this electronic fuse 22.

[0042] To assess whether the previously described problem occurs only in rare exceptional cases or is to be expected regularly, the following consideration can be made. Assuming a generator voltage of 14 V to 15 V and a critical current limit, the reaching of which opens the circuit, and an exemplary electronic fuse 22 of 300 A (i.e., with a tripping current of 300 A), the short-circuit resistance for the entire short-circuit path is approximately 50 mΩ. If the total resistance of a short-circuit path is above this limit, the short-circuit current would be below the current limit of the electronic fuse, and thus selectivity would be ensured. Conversely, however, it is to be expected that all cases exhibiting a short-circuit resistance below the specified limit would lead to a violation of selectivity, since the short-circuit current in this case would cause the electronic fuse 22 to trip.A comparison of actual on-board network configurations with this estimated limit shows that violations of selectivity can be expected, for example in the case of common fuses 42 up to a rated current of 40 A - the limit naturally depends on the current maximum of the electronic fuse 22.

[0043] According to the current state of the art, this problem can only be solved by exclusively using electronic switching elements / fuses 22, which would significantly increase the complexity and / or effort and / or product costs. The embodiments described below solve this problem, as detailed below.

[0044] The following describes a fuse arrangement according to one exemplary embodiment, as well as several variants. In this description, the at least one energy storage device is designed as an example of at least one capacitor. Other embodiments for the at least one energy storage device are conceivable, such as an embodiment of at least one battery or at least one accumulator. Furthermore, the capacitor and the load are each connected to ground as examples. This is not to be understood as a limitation. The capacitor and / or the load can each generally be connected to a reference potential. The reference potential can be at a lower potential than the supply side, e.g., than the respective supply line path. This lower potential can be ground. Furthermore, the non-electronic fuses are designed as examples of fuse links. This is to be understood as an example only.Other designs for non-electronic fuses are conceivable.

[0045] Fig. Figure 2 shows an on-board electrical system with a fuse arrangement 100 according to an exemplary embodiment. The fuse arrangement 100 has at least one supply path 200 and at least one sub-path 400. An electronic fuse 220 is arranged in each of the at least one supply path 200. An input of the at least one supply path 200 can be connected to at least one power source 240 of a vehicle. A fusible link 420, as an example of a fuse or a non-electronic fuse, is arranged in each of the at least one sub-path 400. An input of the at least one sub-path 400 is connected to an output of the at least one supply path 200. An output of the at least one sub-path 400 can be connected to a load 440. The load 440 is connected, by way of example, to ground as an example of a reference potential.The fuse arrangement 100 and the vehicle electrical system can thus be described as a vehicle electrical system with two fuse levels, namely the higher fuse level of the at least one supply path 200 and the lower fuse level of the at least one sub-path 400. Even if the fuse arrangement 100 and the vehicle electrical system are in . Fig. While examples 2 show only two backup levels, more than two backup levels may also be provided.

[0046] The fuse arrangement 100 comprises at least one capacitor 300. The capacitor 300 is arranged between the at least one supply path 200 and the at least one sub-path 400. More precisely, the at least one capacitor 300 is arranged between the at least one supply path 200 and the at least one sub-path 400 such that one terminal of the at least one capacitor 300 is connected to the output of the at least one supply path 200 and the input of the at least one sub-path 400, and another terminal of the at least one capacitor 300 is connected, for example, to ground. In other words, the capacitor 300 is connected to an output of the at least one supply path 200 and an input of the at least one sub-path 400.The described capacitor 300 can therefore be installed directly after the electronic fuse 220, so that the generic load path can be modified to "power source - electronic fuse - capacitor - fuse - load". Only one capacitor 300 is required per electronic fuse 220. That is, for example, only one capacitor 300 is inserted into the load path for each electronic fuse 220.

[0047] In Fig. Figure 2 shows three supply paths 200 as an example of at least one supply path 200. Accordingly, three power sources 240 (e.g., one power source 240 per supply path 200) and three electronic fuses 220 (one electronic fuse 220 per supply path 200) are provided. Three sub-paths 400 are connected to the middle (second) of the three supply paths 200 as an example of at least one sub-path 400. One or more sub-paths 400 are also provided on each of the upper (first) and lower (third) supply paths 200, for example, three sub-paths 400. A fuse 420 is provided in each of the three sub-paths 400 of the middle (second) supply path 200. In addition, the three sub-paths 400 of the middle (second) supply path 200 are each connected to a consumer 440 (even though this is only shown for the middle (second) of the three sub-paths 400).The consumers 440 are each connected to ground by way of example. Likewise, in each of the sub-paths 400 of the upper (first) and lower (third) supply path 200 (not shown), a fuse 420 is provided by way of example. Likewise, each of the sub-paths 400 of the upper (first) and lower (third) supply path 200 (not shown) is connected to a consumer 440, which in turn is connected to ground by way of example.

[0048] Furthermore, a capacitor of 300 is provided for each 200 supply path. Therefore, in Fig. Figure 2 shows three capacitors 300 as an example, although only a single capacitor 300 is shown for simplicity. Each of the three capacitors 300 is connected to a supply path 200 and to the sub-paths 400 of the corresponding supply path 200 to which it (i.e., the capacitor 300) is connected. With respect to the middle (second) supply path 200, this means that the output of the supply path 200 is connected to a first terminal of the capacitor 300. The first terminal of the capacitor 300 is also connected to an input of the three sub-paths 400 that are connected to the middle (second) supply path 200. A second terminal of the capacitor 300 is, for example, connected to ground.

[0049] If a short circuit occurs in any of the loads 440, the electrical energy is not only drawn from the primary energy sources 240, which provide the power supply during normal operation, but also from at least one capacitor 300. This means that the short-circuit current, which destroys the fuse 420 assigned to the respective load 440, does not have to flow entirely through the electronic fuse 220, which is located in the supply path 200 connected to the respective load 440. This ensures that, with correct dimensioning of the capacitor capacitance, the short-circuit current from the primary energy sources 240 does not reach the maximum current / tripping current of the electronic fuse 220. It is expected that initially, the main current will be supplied by the capacitor 300, since it can be connected to the loads 440 with a lower resistance.As the short-circuit duration increases, and thus the amount of current already drawn from capacitor 300 increases, its voltage decreases, and consequently the current flows through it. This, in turn, leads to an increase in the current flowing through electronic fuse 220. The precise dimensioning of the capacitor capacitance depends on the installed fuses 220 and 420.

[0050] Energy can be drawn from capacitor 300 until the voltage difference between the capacitor plates corresponds to the voltage drop along the path, starting at the electronic fuse 220. As the short-circuit current increases, the on-board voltage across capacitor 300 decreases, allowing larger amounts of current to be drawn from capacitor 300. This has a balancing effect.

[0051] More precisely, the lower the resistance of the short-circuit path, the higher the short-circuit current will be. Thus, the current along the entire path can become so large that the entire voltage of the power source drops across it. According to Ohm's law, the individual voltage drops across individual conductors or contacts on the path are proportional to their respective resistances. This means that if the majority of the short-circuit resistance is located before capacitor 300, for example, because the load 440 and the short circuit itself have very low resistance connections, a lower voltage will be present across capacitor 300. In other words, capacitor 300 initially has its normal voltage, i.e., the voltage that existed between its plates (in the case of a parallel-plate capacitor) before the short circuit occurred.However, this is a dynamic process, and the more energy is drawn from capacitor 300, the lower the voltage becomes. This continues until capacitor 300 reaches the voltage that would be present at that point in the electrical system if there were no capacitor 300 and the entire short-circuit current were drawn solely from the primary energy source 240. Therefore, when referring to a voltage difference across capacitor 300, this difference is meant, for example, the difference between the voltage in "normal operation" and the voltage in a fault condition ("fault operation") after the maximum energy has been drawn. This difference corresponds to the voltages without capacitor 300 in "normal operation" and "fault condition" at the installation location (more precisely, not the voltage itself, but the voltage difference between the two points where capacitor 300 is connected).If, for example, the negative plate of capacitor 300 is connected to ground (=zero potential), the voltage difference across capacitor 300 corresponds to the voltage applied to the positive plate of capacitor 300.

[0052] For example, if different loads are considered, such as a first load with relatively high resistance and a second load with relatively low resistance, the short-circuit current will be higher in the event of a short circuit at the second load. This results in a higher voltage difference between the "normal voltage" and the "fault voltage," meaning more energy can be drawn from capacitor 300 than would have been the case with a short circuit at the first load. Therefore, it can be said that the more severe the fault, i.e., the lower the resistance of the short-circuit path, and thus the higher the short-circuit current, the more energy can be drawn from capacitor 300. This can be understood as the described stabilizing effect. That is, as the short-circuit current increases, the voltage across capacitor 300 decreases.

[0053] If capacitor 300 is disconnected from the battery voltage after the vehicle is switched off (e.g., at terminal 15), this can lead to relatively high current spikes during startup. In the worst case, the initial charging of capacitor 300's capacity could cause the electronic fuse 220 to blow. Terminal 15 is sometimes also referred to as ignition positive or switched positive. Ignition positive or switched positive refers to the positive terminal of a vehicle battery that is switched by the vehicle's ignition switch. Originally, ignition positive supplied only the ignition system with electrical current. This is necessary for the gasoline engine to receive a spark that initiates the combustion of the fuel-air mixture. To switch off the engine, the ignition is turned off. Over time, more and more electrical consumers have been added.Those that are only needed during operation can, for example, be connected to the ignition-switched power supply. For example, the 300 Ω capacitor can be connected to the ignition-switched power supply.

[0054] In principle, there are several ways to prevent the aforementioned undesirable effect (when charging capacitor 300). These methods can be combined with each other as desired or implemented independently.

[0055] According to one possibility, a first control component can be in a control unit (not shown in Fig. 2) be provided for. The first control component of the control unit can be configured to implement a controlled switch-on routine. In this switch-on routine, the current flow is gradually increased to avoid peak currents. In particular, the current flow through the electronic fuses 220 is increased so slowly that peak currents are reduced or avoided that would cause the respective electronic fuses 220 to trip.

[0056] Additionally or alternatively, a second control component can be provided in the control unit. This second control component can be configured to control the electronic fuses 220. For example, the second control component can be configured to control the electronic fuses 220 in such a way that they do not begin measuring the current immediately after being switched on, but only after a predetermined time period. In this case, the electronic fuses cannot trip during the predetermined time period. However, this has the disadvantage that semiconductor switches could overheat due to their relatively low thermal mass.

[0057] A second option is in Fig. Figure 3 illustrates this. According to the second option, an additional resistor 320 is connected in series with capacitor 300, limiting the current flow. When capacitor 300 is charging, the resistor 320 causes a lower current to flow into the capacitor path and thus also into the associated supply path 200. This limitation reduces the probability of the electronic fuse 220 tripping during capacitor 300 charging. With this option, it is accepted that in the event of a fault, capacitor 300 may not be able to provide as much electrical energy as in the case without resistor 320 (see Figure 3). Fig. 2) Furthermore, the second option increases local power losses and thus the thermal load.

[0058] A third option is in Fig. Figure 4 shows the third possibility. A diode arrangement 340 is connected in series with the capacitor 300 on the input side. One possible implementation of the diode arrangement 340 is shown schematically in Figure 4. Fig. As indicated in Figure 5, according to this exemplary implementation, the capacitor 300 is connected to the vehicle electrical system via two separate paths. These two separate paths feature an antiparallel diode circuit, allowing the capacitor 300 to be charged and discharged on different paths. One charging path for the capacitor 300 has a first diode 342 and a charging resistor 344. One discharging path for the capacitor 300 has a second diode 346 and a discharging resistor 348. A higher charging resistor 344, for example, 0.1 Ω to 0.5 Ω (e.g., 0.3 Ω), limits the inrush current. A lower discharging resistor 348, for example, 1 mΩ to 20 mΩ (e.g., 10 mΩ), allows for the extraction of high current peaks in the event of a short circuit.The intrinsic voltage drop across diodes 342 and 346 ensures that capacitor 300 can only be charged to a lower voltage and that, starting from this reduced voltage, an additionally reduced voltage difference is available for discharging. The momentary power losses across diodes 342 and 346 also necessitate that the system be thermally inert enough to prevent overheating.

[0059] This means that, in order to prevent the limiting current of the electronic fuse 220 from being reached while the capacitor 300 is charging, for example after ignition, the diode circuit 340, which defines a unidirectional charging and discharging path with adapted resistors 344 and 348, can be used. Both resistors 344 and 348 can be on the order of a few milliohms, but can be dimensioned differently.

[0060] In summary, it can be said that to resolve the issue relating to Fig. 1a and Fig. As described in section 1b, it is proposed, for example, to install a capacitor 300 directly behind the electronic fuse 220 to solve the problem. This ensures that in the event of a short circuit (of a load 440), part of the charge of the capacitor 300 – depending on the difference between the charging voltage and the local short-circuit voltage as well as the capacitance of the component – ​​can flow away via the short-circuit path, and this current does not have to flow through the electronic fuse 220. Thus, part of the energy required to open the fuse 420 does not come directly from the energy source 240, e.g., from the battery or the generator in the event of a short circuit, but can first be stored locally in the capacitor 300 and drawn from it.

[0061] As a concrete example, a capacitor 300 with a capacitance of approximately 5 F can be used. With a capacitor 300 dimensioned in this way, it can be expected that about 90% of all critical cases can be covered, and the additional installation of a capacitor 300 ensures selectivity even in combination with an electronic fuse 220 and a thermal fuse 420. Furthermore, it can be assumed that an increase in this capacitance is not necessary and that optimal dimensioning can be in the aforementioned order of magnitude.

[0062] The implementation described herein reduces problems inherent in the prior art by incorporating a capacitor as a third component alongside fuses (e.g., cartridge fuses) and electronic switches. This capacitor ensures compatibility between the two switching elements, thus guaranteeing selectivity in a cost-effective manner. In addition to the primary effect described, the capacitor's integration into the vehicle's electrical system also provides voltage stabilization, as rapid voltage dips, such as those caused by brief load changes in individual components like an electric power steering system, are buffered by its capacitance.

Claims

[1] Fuse arrangement (100) for an on-board electrical system of a vehicle, wherein the fuse arrangement (100) comprises: at least one supply path (200) in which an electronic fuse (220) is arranged, wherein an input of the at least one supply path (200) can be connected to at least one energy source (240); at least one sub-path (400) in which a fuse (420) is arranged, wherein an input of the at least one sub-path (400) is connected to an output of the at least one supply path (200) and an output of the at least one sub-path (400) is connectable to a consumer (440); and at least one energy storage device arranged between the at least one supply path (200) and the at least one sub-path (400) such that a connection of the at least one energy storage device is connected to the output of the at least one supply path (200) and the input of the at least one sub-path (400), wherein the at least one supply path (200) has a plurality of supply paths (200) or is designed as a plurality of supply paths (200) and the at least one energy storage device has a plurality of energy storage devices or is designed as a plurality of energy storage devices and each terminal of the plurality of energy storage devices is connected to an associated output of one of the plurality of supply paths (200). [2] Safeguard arrangement (100) according to claim 1 , wherein which has at least one subpath (400), a plurality of subpaths (400), or is designed as a plurality of subpaths (400), and on which at least one feeder path (200) several of the plurality of subpaths (400) are arranged. [3] Safeguard arrangement (100) according to claim 1 or 2, further comprising a control unit which is configured as follows: during a switch-on process, to limit the current flow via the at least one supply path for charging the at least one energy storage device to a predetermined limit value and / or to gradually increase the current flow via the at least one supply path (200) for charging the at least one energy storage device; and / or During a switch-on process, the electronic fuse (220) of the at least one supply path (200) is switched on after a predetermined time period to measure a current flow via the at least one supply path (200) for charging the at least one energy storage device. [4] Safety arrangement (100) according to one of claims 1 to 3, wherein the safety arrangement (100) further comprises at least one resistor (320) which is connected in series with the at least one energy storage device. [5] Safety arrangement (100) according to one of claims 1 to 4, wherein the safety arrangement (100) further comprises at least one diode arrangement (340) which is connected in series with the at least one energy storage device. [6] Fuse arrangement (100) according to claim 5, wherein the diode arrangement (340) comprises a first diode (342), a first resistor (344), a second diode (346) and a second resistor (348), wherein the first diode (342) is configured and arranged such that its forward direction points towards the energy storage, and the second diode (346) is configured and arranged such that its forward direction points towards the output of the at least one supply path (200) and the input of the at least one sub-path (400), and wherein a resistance value of the first resistor (344) is greater than a resistance value of the second resistor (348). [7] Safety arrangement (100) according to one of claims 1 to 6, wherein another terminal of the at least one energy storage device is connected to a reference potential, for example to ground and / or wherein the consumer (440) is connected to a reference potential, for example to ground. [8] A safety arrangement (100) according to any one of claims 1 to 7, wherein the safety device (420) comprises a non-electronic safety device or is designed as a non-electronic safety device, for example a fuse or is designed as a fuse; and / or wherein the at least one energy storage device has at least one capacitor (300) or is designed as at least one capacitor (300). [9] Vehicle electrical system, wherein the electrical system comprises: a security arrangement (100) according to one of claims 1 to 8; at least one energy source (244) connected to an input of the fuse arrangement (100); and at least one consumer (444) connected to an output of the fuse arrangement (100). [10] Vehicle comprising a safety arrangement (100) according to one of claims 1 to 8 and / or an on-board electrical system according to claim 9.

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